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UNESCO-NIGERIA TECHNICAL & VOCATIONAL EDUCATION REVITALISATION PROJECT-PHASE II NATIONAL DIPLOMA IN SCIENCE LABORATORY TECHNOLOGY TAXONOMY OF LIVING ORGANISMS COURSE CODE: STB 111 YEAR I- SE MESTER I THEORY Version 1: December 2008 1 TABLE OF CONTENTS WEEK 1: General Classification of Living Organisms………………………………………3 WEEK 2: General Classification of The Plant Kingdom……………………………………..11 WEEK 3: Classification of Algae……………………………………………………………….15 WEEK 4: Classification of Fungi……………………………………………………………….19 WEEK: 5 Classification of Bryophyta…………………………………..……………………...22 WEEK 6: Classification of Spermatophyta……………………………….……………………26 WEEK 7 : Common Flowering Plant (Monocotyledonous Plant Families)….………………31 WEEK 8: Family Bambacaceae…………………………………………………..…………….37 WEEK 9: Technique For Collecting and Preserving Common Flora (Herbarium)……..….42 WEEK 10: General Classification of the Animal Kingdom……………………………………46 WEEK 11: Phylum Chordata…………………………………………………………………….64 WEEK 12: Class Amphibia ………………………………………………………………………67 WEEK 13: External Features of a Tilapia ……………………………………………………...71 WEEK 14: Protochordates as A Link Between Invertebrates And Vertebrates ………….…76 WEEK 15: Preservation Methods of Common Vertebrates and Invertebrates ……….........78 2 WEEK 1: GENERAL CLASSIFICATION OF LIVING ORGANISMS 1.0 Introduction The classification of living organisms has been controversial throughout time. Aristotle’s system distinguished only between plants and animals on the basis of movement, feeding mechanism, and growth patterns. In 1735 the Swedish naturalist Carolus Linnaeus formalized the use of two Latin names to identify each organism, a system called binomial nomenclature. He grouped closely related organisms and introduced the modern classification groups: kingdom, phylum, class, order, family, genus, and species. Single-celled organisms were observed but not classified. In 1866 German biologist Ernst Haeckel proposed a third kingdom, Protista, to include all single-celled organisms. Some taxonomists also placed simple multicellular organisms, such as seaweeds, in Kingdom Protista. Bacteria, which lack nuclei, were placed in a separate group within Protista called Monera. In 1938 American biologist Herbert Copeland proposed a fourth kingdom, Monera, to include only bacteria. This was the first classification proposal to separate organisms without nuclei, called prokaryotes, from organisms with nuclei, called eukaryotes, at the kingdom level. In 1957 American biologist Robert H. Whittaker proposed a fifth kingdom, Fungi, based on fungi's unique structure and method of obtaining food. Fungi do not ingest food as animals do, nor do they make their own food, as plants do; rather, they secrete digestive enzymes around their food and then absorb it into their cells. Below is the present classification system currently in use: 3 Monera Protista (Prokaryote) Fungi Plantae Animalia Unicellular Multicellular Green Multicell Eukaryotes Eukaryotes Multicell Animals 1.1 Plant Kingdom The kingdom Plantae accounts for the largest proportion of the earth’s biomass with its approximately 250,000 species of mosses, liverworts, ferns, flowers, bushes, vines, trees, and other plants. Aquatic and terrestrial plants are the basis of all food webs. They contribute life-supporting oxygen to the atmosphere and provide humans with the fossil fuels, medicines, and other substances so important to our present existence. Figure 1 Typical Picture of Rain Forest 4 1.2 Plant Classification The first scientific study of plants was the attempt to classify them. At first, because of the limited knowledge of plant structures, artificial classifications, beginning with the most ancient one into herbs, shrubs, and trees, were necessary. These simple categories merely cataloged, in a tentative way, the rapidly accumulating material, in preparation for a classification based on natural relationships. Modern taxonomic classification, based on the natural concepts and system of the Swedish botanist Carolus Linnaeus, has progressed steadily since the 18th century, modified by advances in knowledge of morphology, evolution, and genetics. Thus, taxonomy is concerned with the description, identification and naming of plants and their classification into groups based on resemblances and differences mainly in their morphological, reproductive and anatomical characteristics. The objectives is to describe, name and classify plants is such away that their evolutionary trend is brought out i.e. from simpler, earlier and more primitive types to more complex, more recent and more advanced types. The earlier classification of plants were based on either economic value e.g. cereal, medicinal, fibre yielding, oil yielding fruits, vegetables etc or on gross structural resemblance e.g. herbs, shrubs trees, climbers etc. Plants that do not fit into such classification were usually ignored 1.3 Types of system of classification There are two Types of system of classification, these are: Artificial system of classification and Natural system of classification. 1.3.1 Artificial system of classification In Artificial system of classification, one or few characters are arbitrary selected and plants are arranged into groups according to these characters. Related plants 5 are often placed in different groups. Unrelated plants are put in same group because of the absence or presence of a particular character. This system does not indicate the natural relationship that exist among the individuals of a group. Nevertheless, the identification of an unknown plant is rendered much easier by this system. 1.3.2 Natural system of classification In Natural system of classification all important characters are taken into consideration. Initially, only morphological and anatomical characters are considered and plants are grouped according to these characters. Later, cytological, reproductive, physiological, genetic characters are taken into consideration including the geographical distribution of the plant. Plants are first classified into few large groups. These are further divided and sub-divided into smaller groups until the smallest group is reached (i.e species). This system gives a true idea of natural relationship existing between the different plants. The natural system has two main aspects i.e Systematics and Nomenclature. Systematics This is concerned with putting plants into groups. The smallest group is the “SPECIES’ which is defined as a group of individuals having a close resemblance with one another structurally and functionally. The members belonging to the species can interbreed in nature freely and successfully among themselves to give rise to progeny of the same kind. However, there is no sharp demarcation between allied species. The collection of species which bear close resemblance to one another form a GENUS. For example, Fig (Ficus carica), Banya (Ficus bengalensis) and Peepul (Ficus religiosa) are different species but are allied because they 6 resemble one another in their reproductive organs-inflorescence, flower, fruit and seed. The genus name is Ficus. The groups of genera which show general structural resemblance to one another form a FAMILY. For example, the genera Gossypium, Hibiscus, Thespesia, Sida, Abutilon and Malva belong to the family Malvaceae. The families that are similar are grouped into an ORDER. Orders that are similar are grouped into a CLASS. Classes that are similar are grouped into a DIVISION. And Divisions that are similar are grouped into KINGDOM i.e PLANT KINGDOM. According to this system, plant kingdom is divided into three divisions namely BRYOPHYTA PTERIDOPHYTA and SPERMATOPHYTA. However, there is no uniformity in size of categories. Sometimes there are sub-categories such as sub-division, sub-class, sub-order and sub-family. Nomenclature This is concerned with naming of groups and the individuals of a group. Generally, the plant name has two parts. The first part is the Generic name i.e Genus to which the plant belongs. The second part is the Specific name i.e Species to which the plant belongs. This system is known as Binomial System of Nomenclature. It was first established by Carolus Linnaeus and later settled by the International Botanical Congress in 1932. Attempts have been made to establish a universal name endings for the higher categories. Class names usually ends in–aceae for example MYXOPHYCEAE. Family names end in-ae for example, Compositae, Palmae; Orders end in-ales for example Filicales. Divisions end in – phyta for example Spermatophyta. There are rules guiding the naming of plants, and this includes: 1. Generic name starts with a capital letter and specific name starts with a small letter, example Mangifera indica. 2. No two plants should have the same botanical name 7 3. Where plant has more than one name, the first name is the valid. 4. Names are underlined separately if written or typed 5. Names are printed in italics 6. Name of author is abbreviated, and it is found after the name of Species example Mangifera indica, Linn. Kingdom protista This consists of unicellular, eukaryotic organisms such as the protozoa algae , like volvox spirogyra etc. The group algae has the following characteristics: This group has the following general characteristics - Thalloid body not differentiated into root, stem and leave with little cellular differentiation. - Contain green pigment (chlorophyll) - Some algae contain other pigments like blue, yellow, red, brown etc in addition to the chlorophyll. - Autotrophic in nutrition - Store excess glucose in form of starch - Reproduce by fragmentation spore formation or conjugation - Cell wall made up of cellulose. - Body made up of true parenchymatous cells - Some are unicellular, others are multicellular. - The multicellular species could be filamentous or colonial - They are mainly aquatic and are considered as the most primitive of plants - Example of plants in this group include: Blue green algae (Nostoc, Anabaena,) - Green algae(Volvox,Spirogyra,Cladophora,Chara,Nitella) - Yellow green algae (Vaucheria) Diatoms, 8 - Brown algae (Laminaria,Dictyopta) Figure 4: Spirogyra Kingdom Fungi This kingdom has the following characteristics: - They are mainly terrestrial but the lower forms are found wide spread in aquatic environment. - Body is composed of thread like structure called hyphae (collectively the filamentous fungal body is called MYCELIUM) - Body not differentiated into roots, stem and leaves - Lack chlorophyll, the colour may be due to pigmentation in cell walls, cytoplasm or oil globules in the cells. - Exhibit heterotrophic mode of nutrition - They can be either parasitic or saprophytic but some form symbiotic association with higher plants (Mycorrhizae) and some form natural unions with algae (Lichens) - Excess sugar stored in form of glycogen - Body is made up of pseudoparenchymatous tissues - Cell call made of cellulose mixed with chitin. - Contain other pigment in cell wall or cell cavity. 9 - Almost all show an asexual or imperfect spore stage and many reproduce sexually at a “perfect stage” through true sexual fusion of gametes. - They have a variable life cycle - Example slime fungi, Pythium, Albugo, Mucor Rhizopus Yeast Agaricus, Puccinia. Diagram of Rhizopus 10 WEEK 2: GENERAL CLASSIFICATION OF THE PLANT KINGDOM (CONTINUED) 2.0: MAJOR GROUPS OF PLANT KINGDOM There are different varieties of plants on earth and these plants have been classified in to three major groups.Viz: 1. Bryophyta (liverworts & mosses) 2. Pteridophyta (ferns) 3. Spermatophyta (seed producing plants) 2.3: Division: Bryophyta This group has the following general characteristics: - Body divided into root, stem and leaf like structures. The root like structures are called RHIZOIDS - Dichotomous branching is common - Contain photosynthetic pigment similar to that of higher plants chlorophyll. - Well defined sexual reproduction with clear cut heteromorphic alternation of generation. - Mainly terrestrial, few are aquatic - Low degree of tissue differentiation - Persisting plant body is the haploid gametophyte, diploid sporophyte is always wholly or partially dependent on the gametophyte. - Spores are always of one kind i.e homosporous. - The spores germinate in to a structure called protonema 11 Figure 5: Mosses growing on an old tree trunk. 2.4: Division Pteridophyta This group has the following general characteristics: - Body divided into root, stem and leaf system - Have high degree of internal tissue differentiation with conducting system of xylem and phloem - Dichotomous branching is common - Growth from apical cell - Contain photosynthetic pigments-chlorophyll a and b with caretonoids - Clear – cut heteromorphic alternation of generation - Spores may be homosporous (Identical) or heterosporous (of two kinds) - Well defined sexual reproduction with antheridia (male gametes) and Archegonia (Female gametes) - Persisting plant body is the Diploid sporophyte which is independent of the haploid gametophytes 12 - Mainly terrestrial with few aquatic members Figure 6: Structure of a frond showing the under side of the leaves 2.5: Division Spermatophyta This group has the following general characteristics: - Body differentiated into root, stem and leaves - Dichotomous branching is rear - Show highest degree of internal differentiation - Growth is from apical meristem - Secondary thickening is common - Contain photosynthetic pigment-chlorophyll a and b with caretonoids - Clearly defined alternation of generation - Well defined sexual reproduction and fertilization by means of a pollen tube - Produce seeds which may be borne naked or in a closed structure (fruit) - Mainly terrestrial but with some obviously derived aquatic representatives, example Cycas, Maize, Rose etc. 13 Figure 7: Showing the structure of Maize plant and its comb 14 WEEK 3 CLASSIFICATION OF ALGAE The division Phycophyta is divided into the following classes 1. Class: Myxophyceae or Cynophyceae (Blue-green algae) Marine, fresh water and wet surfaces no internal cell membranes separating nuclear materials, chlorophyll, and mitochondria e.t.c. from the cytoplasmic background i.e. prokaryotic. No flagella storage compounds. Cyanophycin, oil and glycogen. No sexual reproduction but possibly genetic interchange between individuals. Asexual reproduction by amitotic cell: fragmentation, non-motile resting spores a vegetative cells. Commonly algal partners in lichens e.g. Anabaena, nostoc Blue pigment (phycocyanin) is present in addition to chlorophyll. Example, Nostoc, Oscillatoria, Anabaena. 2. Class: Euglenophyceae: These are simple organism from which evolution of other plants has started example Euglena. 3. Class: chlorophyceae (green). Mostly following, few marine occasionally terrestrial. Unicellular, colonial filament and expanded thalloid forms food reserve starch cellulose cell wall Possess green pigment only e.g. Volvox, Spirogyra Chlamydomonas, Pandorina. 4. Bacillariophyceae (diatoms). marine fresh water and any damp surface. Constitute much of the phytoplankton, free floating and epiphytic, unicellular or in chain or in group of cells unique wall form in 2 overlapping halves (Petri dish) silicified, sculptured, eukaryotic food stored as oils and leucosin. Asexual reproduction by cell divition in which generation became successively smaller Mostly free-Floating. Boat, rod, disc-shaped. 5. Phaeophyceae (Brown). Entirely marine, eukaryotic form range from fixed branched filamentous to partially organized expanded thallus food reserve are laminarin and mannitol 15 Show alternation of generation Possess brown pigment (fucoxanthin) example Focus, Laminaria 6. Rhodophyceae (red). Possess red pigment-phycoerythrin example Polysiphonia, Batrachospernum. Below are the structural examples of members of the Division Phycophyta Diatoms - - Mostly are celled algae - Posses variety6 of forms - Single cells, may form filaments or colonies - Found in fresh as well as salt water and in wet grounds Boat shaped, rod-shaped, disc-shaped wedge-shaped, oval-shaped, rectangular shaped e.t.c - Wall is made up of two halves or valves, an older one called Epitheca fitting closely over the younger valve called hypotheca (inner valve) - The valves are made up of pectin impregnated with silica. - They have numerous fine lines which are really very fine dots and radially symmetrical in the centric and bilaterally symmetrical in elongated diatoms (Pennales) In some Genera, there are ingrowths of walls which are called central or polar nodules according to position. A line called raphae extends from central to the polar, nodules. The protoplasm consists of a thin layer of cytoplasm within the cell wall. One large or many small yellow to golden-brown plastids of varied shapes and sizes, a central nucleus suspended by cytoplasmic threads or by a broad cytoplasmic band, and a central vacuole. Gold brawn colour of plastids is due to a pigment 16 called diatomin in addition to chlorophyll. Pyrenoids may or may not be present. If present, are without the starch envelop. Reserve foods are globules of fats and insoluble complex substance called volutin. No starch in diatoms. Figure 8: Diagram of a Diatom Spirogyra - It is an unbranched filamentous algae - It consist of a single row of cylindrical cells joined end to end - Each cell is surrounded by a membrane and a cell wall made up of cellulose and pectin. - A thin layer of mucilage covers the cell wall making it slimy to touch - The filament is not differentiated into a base and apex. - Each cell has a thin layer of cytoplasm in which 2 or more spiral chloroplast are embedded. 17 - A nucleus lies in the centre of the cell and is suspended by cytoplasmic thread. - A large vacuole occupies the centre of the cell. - On the chloroplast are a number of small nodular protoplasmic bodies called Pyrenoids and around them minute starch grains are deposited. Figure 9: Diagram of spirogyra cell. 18 WEEK 4 Classification of Fungi The division mycophyta is divided water 5 classes. 4.1 Class: Myxomacetes (slime fungi). - Grow in damp, shady places in soil such in humus - Require moisture and darkness for normal growth - Contain pigments like yellow, orange, brown red or colourless - Animal like in their vegetative stages and plant like in their reproductive stages. Figure 10: Diagram of a club fungi 4.2 Class: Phycomycetes - Many are aquatic or damp loving forms, fewer fully terrestrial - Mycelium is unseptate and coenocytic - Sporangium has many sporangiospores - Sexual reproduction is either oogamous or isogamous. - Asexual reproduction by zoospores, conidiospores or sporangiospore 4.3 Cell wall often cellulose food reserve is oil glycogen Example pythium, phytophtora, mucor, etc Class: Ascomycetes 19 - Terrestrial, parasitic or saprophytic - Often highly specialized - Mycelium is of septate hyphae - Protoplast is uninucleated or binucleated - Asexual reproduction by non motile spores usually conidiophore - Reproductive structure are asci e.g Sacchromyces, Penicillum, etc 4.4 Basidiomycetes (club fungi) - Saprophytes or parasites - Often highly specialised - Mycelium is of septate hyphae - Cells are usually binucleate with haploid nuclei - Asexual reproduction by conidiospores Example Agaricus, puccinia, ustilago 4.5 Deutromycetes (fungi imperfecti) - Saprophytes or parasites - Reproductive structures are the conidia - Have imperfect life-history e.g fusarium, Helminth osparium 4.6 Morphology of Mucor (saprophyte) Structure-Mucor grows on animal dung wet shoes, moist bread et.c spreading like a cobwebs. Body is composed of white delicate cottony threads called mycelium. The hyphae are very much branched, but are coenocytic i.e unseptate and having many nuclei. Only in older parts, and during development of reproductive structure are there any cross walls formed. As well as ramifying profusely 20 outside the substrate, the fungus sends countless fine branching hyphae in to the food materials from which it derives its nourishment. Diagram of Mucor Pythium (Parasite) - Mycelium has hyphae that are long slender, branched, unseptate and coenocytic. - Causes “damping off” disease in crops like tobacco, mustard, ginger, cress etc under conditions of overcrowd and over watering. - Attacks the bases of seedlings feeding on them saprophyticlaly. - Facultative parasite. - Mycelium of the fungus runs in all direction through the intercellular spaces and into the living cells of the host (i.e seedling) 21 Week: 5 Classification of Bryophyta The division bryophyta constitute the non vascular plants and is divided into 3 classes 5.1 Class Hepaticae (liverworts) Gametophyte is dorsovetral, prostrate and thalloid in nature - Dichotomous branching is common - Growth is from apical cell or row of cells - Sporophyte is sterile tissue, no chlorophyll and in dependent on the gametophyte example marchantia, porella, pellia 5.2 Class: Anthocerotae (horned liver wants) - Gametophyte is simple and thalloid - Sporophyte is complex - E.g anthoceros 5.3 Class: Musci (mosses) - Gametophyte is erect (in most cases) differentiated into an axis with leaf like structures above ground. - Growth is from a single apical cell - Sporophyte show a high degree of differentiation - Contains chlorophyll and possess of stomatal aperture e.g funaria, sphagnum, polytrichum. 5.4 Morphology of Marchantia - Plant is thalloid with dichotomous branching - Dorsoventral symmetry. Has distinct mid-rib - Grows on damp ground or old walls forming a green carpet 22 - The thallus beans on it ventral side a unicellular rhizoids, a raw of scales along the midrib, 2 or 3 raws of scales on each side of the mid-rib with the outer row being close to the margin of the thallus - On the dorsal side, there are a number of cup-like outgrowths called GEMMA cups on the mid-rid. - Male plant beans special reproductive branches called antheridiophores with a disc or receptacle on top - Female plant beans the archegoniophores with disc or receptacle on top. 5.5 Classification of pteridophytes The division Pteridophyta constitute the vascular plants and is divided in to the following classes: 5.6 Class: Lycopsida Members of this class are of world wild distribution with some fossil forms and a few living forms. The sporophyte is differentiated in to root stem and leaf but the leaves are always small in relation to stem size (Microphyllous). There is no leaf gaps in the stele. There are homosporous and heterosporous representatives. The sporangia aggregated in to cones or strobila usually at the ends of branches example Lycopodium, Selaginella. Diagram of Selaginella 23 5.7 Class Pteropsida These are also of word wide distribution with many living and fossil forms. The sporophyte is differentiated in to roots, stem and leaves may be lacking in mature plants. Leaves always large in relation to stem and spirally arranged. Leaf gaps in the stele in most cases. They are Homosporous except in one family (Salviniaceae). Sporangia borne on margins or abaxial faces of leaves, usually in clusters or sori, except in one group of fossil forms, example Dryopteris. 5.8 Class Psilotopsida The sporophyte is rootless and the shoot is composed of branches only or with small leaves spirally arranged. There is no leaf gaps in the stele. They are Homosporous and the sporangia is borne singly at the tips of branches. Example Whisk ferns. 5.9 Class: Psilophytopsida These class comprises of only fossil order 5.10 Class: Sphenopsida The sporophyte is differentiated in to roots, stem and leaf. The leaves are nearly always microphylous and arranged in whorls. There is no leaf gaps in the stem. The sporangia is Homosporous and borne on distinctive sporangiospores in a strobilus, example Equisetum. 24 5.11 STRUCTURE OF SELAGINELLA The saprophyte body is composed of a creeping stem bearing branches more or less regularly spaced. The stem braches develop at much the same rate as the main axis, therefore dichotomy appears to be the case. But in reality, the braches are lateral in development and the branching system is maopodial. The creeping habit keeps all the stems more or less in a horizontal plane and the leaves also expand in this plane to form a markedly dorsal ventral arrangement. The leaves are produced in four rows and are placed in opposite pairs, each pain having one large and are small leaf. The larger leaves originate from the lower lateral surface of a stem and the smaller ones from the upper surface. Each leaf bears a small membranous outgrowth called a ligule which is recognizable in young leaves but which withers and disappears on ageing. Slightly behind each fork in the stem, sooner or later a structure resembling a root develops and grows species, a large tuft of roots may developed at the tip of the rhizospore. A mature fertile plant bears vertical branches which differ from the rest of the stem structure. They are the strobili, bearing sporophylls all of equal size in four vertical rows. In the axils of the sporophylls, the sporangia are developed. 25 WEEK 6 Classification of spermatophyta Divided into 3 classes 6.1 Pteridospermae (seed-bearing ferns) - Have vegetative characteristics of pteridophytes but bear seed-like reproductive structure 6.2 - Farms a link between true ferns and the flavoring plants - All are extinct (No longer in existence) Gymnospermae - Mostly trees and shrubs - Xylem element always tracheids except one order primitive vessels are found. - Flowers are mostly of strobiloid construction and unisexual - Seeds with one integuments and naked e.g Cycas, pins, Taxus Figure Scientific classification Kingdom: Plantae Divisions Pinophyta (or Coniferophyta) - Conifers Ginkgophyta - Ginkgo Cycadophyta - Cycads Gnetophyta - Gnetum, Ephedra, Welwitschia 26 Figure: Coast Douglas-fir cone Angiospermae - World’s dominant vegetation in all habitats - Adopted to life on land - Posses true xylem vessels - Flower consisting of works of sterile and fertile parts. - Flowers usually hermaphrodite - Male gametophyte represented by pollen grain, female by embryosac with of nuclei - Endosperm formed as a result of triple fusion - Seed has two integuments enclosed in specialized cupels called ovary which ripens into a true fruits. 27 Classes of Gymnosperms. Gymnospermae are divided in to three classes, these are: Class: Cycadopsida, example Cycas Class: Coniferopsida example Pinus, Ginkgo Class: Gnetopsida example Gnetum, Ephedra 6.6 Classes of Angiospermae 6.6.1 Sub-class marocotyledam - Mostly herbaceous, few palm but no tree - Adventitious root system - Usually parallel veined leaves - Vascular bundles irregularly arranged in the stem. - Secondary growth is rare - Flaver parts are in threes or multiple of threes - Single cotyledon in the seal - E.g maize wheat 6.6.2 Sub – Class Dicotyledons - Mostly herbs, shrubs and trees - Tap root system - Vert-veined leaves 28 - Vascular bundles arranged in rings in the stem - Secondary growth is usual - Floral parts are in fours or fives (45/55) or multiple of these. - Two cotyledons in the seed (reely one by reduction). 3.7 The structure of a gymnosperm pinus plant It is a tall, erect, evergreen trees - can grow up to a height of 45 metres. - Has well developed tap-root and numerous aerial branches with needlelike leaves - Stem is rugged and covered with scale bark - The branches are of two kinds: 1 Long branches (of unlimited growth) in apparent wherls developing from lateral buds and 2 Dry branches (of limited growth). - 1 Leaves are also of two kinds:- Long, green, needle-like foliage leaves, called needle borne only on dway branches (foliar spurs) and 2. Small, brawn, scaly leaves borne on both kinds of branches. The number of needles (leaves) in a cluster varies from 1 to 5 depending on the species Diagram. Structure of Angiosperms - Range in size from minute forms e.g Wolffia to ginat trees - Flaver, plants as the higher seed plant - Ovule matures into a seed and is produced within the space enclosed by a carpet thus are sand to produce enclosed seeds - Matured ovary or fruit exhibit a wide variety of forms. May be simple or compound fruits, dry or flashy fruit - Leaves are megaphylls, large and broad 29 6.4 Differences between gymnosperms and Angiosperms Gymnosperms Angiosperms 1 Xylem exclusively made tradechied Xylem mainly composed of resin 2 Phloem contain no companion cells Phloem contain companion cells 3 Flavers are simple no calyx no corolla Flavers are complex 4 Flowers always unisexual Flavers unisexual bisexual 5 Air-current is the only pollinating There are many different pollinating agent 6 agents Ovules are freely exposed on the Ovules remain enclosed in the ovary. megasporohyll (carpel) 7 During pollination, pollen grain enter Pollen grain are deposited on the the micropyle and are lodged on the stigma nucleus 8 Male gametophyte presented by a few Male gametophyte reduced to 2 cells usually 2 or 3 a vestigial nuclei only i.e tube nucleus and protahllus 9 Female generator nucleus gametophyte is a large Female gametophyte is represented structure with archegonia embedded in by an 8-nucleate embryo – sac and it, each with on ovum the ovum is free in it without any archegonia. 10 Endosperm formed from vegetative Endosperm is formed from definitive tissue of female prothallus before nucleus only after fertilization and is fertilization and is haploid (n) triploid (3n) cotyledons are 1 or 2. 30 WEEK 7 Common flowering plant families some monocotyledonous plant families 7.0 Characteristics of the family gramineae (poaceae) Habit – Herbs, rarely woody (bamboos) Stem – Cylindrical with distinct nodes and internodes sometimes hallow Leaves – Simple, alternate, with sheathing leaf-base split on the side opposite leaf-blade Flavers- Usually bisexual, sometimes unisexual monoecious. Perianth – Represent by two or three minute scales (lodicules) Androecium – Stamens three, sometimes to, anthers versatile and pendulous Gynoecium – Carpe (3), reduced to one (according to same authors) by fusion or suppression of two, ovary superior, one – celled, with ovule, styles two (but three in baboos, and two fused into one in maize), rarely terminal or lateral stigmas feallery Fruit – caryopsis. Pollination by wind. e.g Grass, Bamboo. Family – Palmae Habit – Shrubs or tree, sometimes climbing Stem- Erect, unbranched and woody. Has scars or shed leaves. Height 45m above Roots – Numerous, fibre developing from base of stem. Leaves – Usually forming a crown, petiole with stout sheathing base. Flowers – sessile, small and inconspicuous but produced in large numbers (12,000 indicate palm regular, hypogenous, unisexual (rarely bisexual), male an female flowers in some inflorescence or in the either monoecious or dioecious. Perianth – in two whorls, 3 + 3 the outer being smaller, usually free, persistent in the female flower Androecium – stamens usually in two whorls 3 + 3 filaments free or connate anthers versatile and two celled Gynoecium carpels (3) OR three ovary superior, unilocular aartiloculer with one or three ovules 31 Fruit – drupe, berry or nut. Pollination by wind, sometimes insects Floral formulae 7.1 Family Liliaceae Habit – herbs, climbers, rarely shrubs and trees with a bulb or rhizome or with fibrous roots Leaves – are simple, radical or cauline or both (radical = cluster of leaves arising from short underground stem an it from the roots cauline = directly borne by the aerial parts of the stem and branches) Flowers – regular, bisexual (rarely unisexual, dionegroud three – mercus and hypogenous, bracts usually small, scarious (thin, dry and membranous) Perianth – Petals are petaloid, usually 6 in 2 whorls 3 + 3 free or (3 + 3) united (i.e polyphyllous and gamohylous respectively) Androecium – stamens are 6 in 2 whorls, 3 + 3 rarely 3, free or united with perianth at the base (epiphyllous), anthers often dorsifixed Gynoecium – carpels (3) syncarpous, ovary superior, ovules usually ∝ (infinite) in two rous, placentation axile, styles (3) or 3. Fruit – a berry or capsule. 7.2 Dicotyledonous Plants 7.2.1 Characteristics of some dicotyledonous Families 7.2.2 Family Leguminosae Habit: Herbs, shrubs, trees, twiners, climbers Leaves: Alternate, Pinnately Compound, rarely simple, stipules 2, usually free Flower: Bisexual and complete, regular or irregular (actinomorphic or Zygomorphic) hypogenous or slightly perigynous Calyx: Sepals usually five with the cold one anterior (i.e away from the axis sometimes (4) . Carolla: Petals usually five, with the odd one posterin 32 Androecium: Stamens usually ten or numerous, sometimes less than 10 by reduction, free or united Gynoecium: Carpel one, ovary one-celled with one to many ovules, superior, placentation marginal Fruit: commonly a legume or pod (dehiscent), sometimes lomentum (in dehiscent) The family is large and is divided into three – subfamilies Subfamilies Caesalpinioideae Mimosoideae Faboideae Scientific classification Kingdom: Plantae Division Magnoliophyta: Class: Magnoliopsida Order: Fabales Family: Fabaceae 33 Diagram of the fruit of Gymnocladus dioicus (1),and a flower of Wisteria sinensis, Faboideae. Two petals have been removed to show stamens and pistil (2) 1 2 Diagram of Legume of Vicia angustifolia (1) and Pisum sativum (2) 1 2 34 7.2.3 Family: Malvaceae Habit: Herbs shrubs, trees Leaves: simple, alternate and palmately viewed Flowers: Irregular, Polypetalous, bisexual, hypogenous, copiously mucilaginous with a whorl of epicalyx Calyx: Sepals (5), valvete Carolla- petals 5, attached to the base of staminal tube Androecium: Stamens numerous, monadelphous (united into one bundle = staminal column/tube), epipetalous (staminal tube adnate to the petals at the base) anthers reinform, unilocular, pollen grains large and spiny. Gynoecium: Carpels commonly (5 to α), ovary superior, 5 to α - loculus placentation axile, style passes through staminal tube, stigma is free as many as the carpels Fruit: Capsule or schizocarp Seed: Endospermic 7.2.3 Family: Compositae e.g Tridax Habit: Herbs and shrubs, rarely twiner or tree Leaves: Simple, alternate or opposite, rarely compound. Flowers: (or flared) are of two kinds. Central ones called disc florets. They are tubular and the marginal ones called ray florets. They are ligulate sometimes all florets ar of the same kind (tubuler or ligulate) 35 Disk Floret: Regular, bisexual, epigenous Calyx:- Modified into hairs= pappus or into scales or absent Corolla:- Petals (5) tubular Androecium: Stamens 5, epipetalous (attached to petals by their filament) syngynesions (anthers united but filaments free). Gynoecium: Carpels (2), ovary interior, 1 – celled with one basal, anatropous ovule, style 1, stigma bifid, Fruit:- crypsela Ray floret: Zygomorphic, unisexual or sometimes neuter (e.g sunflower) and epigenous. Calyx: Modified into pappus, scale or absent Carolla: Petals (5), gamopetalous, ligulate (strap – shaped) Gynoecium: as in disc florets 36 WEEK 8: Family Bambacaceae 8.0 Characteristics: This family has the following characteristics: • Habit: These are large trees • Leaves: These are simple or digitately compound with deciduous stipules • Flowers: The flowers are regular, large, bisexual and hypogynous. • Calyx: This is gamosepalous with (5) sepals. It is valvate, often with an epicalyx. • Corolla: This is polypetalous with 5 petals and imbricate • Androecium: These are 5-∞ stamens, free or polyadelphos.The anthers are two celled sometimes more. The pollen grains are smooth and staminodes are often present • Gynoecium: This is syncarpous, with (2-5) carpels. When 5, the carpels are opposite to the petals. • The ovary is superior, multilocular with 2 -∞ - ovules in each loculus. • Fruit: The fruit is capsule • Seeds: These are small, often very heavy and with scanty or no endosperm. • Eg Bambax, red or silk cotton tree, Bambax ceiba Family Rutaceae (citrus) • Habit: These are shrubs and trees • Leaves: The leaves are simple or compound, alternate or rarely opposite and gland dotted • Flowers: These are regular hypogenous and bisexual. The disc below the ovary is prominent and ring or cap like. • Calyx: There are four or five sepals free or connate below and imbricate. • Corolla: petals four or five free imbricate 37 • Androecium: The number of stamens varies. They can be as many or more often twice as many as the petals or numerous as in citrus. They are free or united in irregular bundles and inserted on the disc. • Gynoecium: These are generally (4) or (5) carpels or ∞, as in citrus. They are syncarpous or free at the base or united and either or seated on a disc. The ovary is generally four or five locular or multilocular as in citrus, with axile placentation. There are usually two ovules in each loculus arranged in two rows. • Fruit: This is a berry, capsule or hesperidium. • Seed: The seeds may or may not have an endosperm. Polyembryony is frequent in citrus Eg lemon , citron, lime, orange and pummelo. Diagram of a Citrus plant. (Citrus reticulata cultivar) Scientific classification Kingdom: Plantae (unranked): Angiosperms 38 (unranked): Eudicots (unranked): Rosids Order: Sapindales Family: Rutaceae Subfamily: Aurantioideae Tribe: Citreae Genus: Citrus 8.2 family meliaceae • Habit: These are mostly trees rarely shrubs. • Leaves: The leaves are pinnately compound and the leaflets are oblique. • Inflorescence: This has an axillary panicle • Flowers: These are regular, often bisexual sometimes polygamous and hypogynous. • Calyx: There are (4-5)sepals (gamosepalous) • Corolla: There are 4-5 petals(usually polypetalous)imbricate • Androecium: There are 8-10 stamens, generally united in to a long or short staminal tube. • Gynoecium: There are (2-5) carpels(syncarpous)the ovary is superior, it is 2-to5-locular,rarely unilocular, with one or two ovules in each chamber. disc is annular surrounding the ovary. • Fruit: The fruit is a capsule, berry or drupe. • Seed: This is often winged, and albuminous eg Mahogany, satin wood. 8.3 Family anacardiaceae • Habit: These are shrubs or trees. Many of them are resinous. • Leaves: These are simple or pinnately compound alternate and exstipulate. • Inflorescence: This is a panicle of many small flowers . 39 • Flowers: The flowers are small, regular and bisexual they are sometimes polygamous, hypogynous to epigynous and usually pentamerous. The disc is present. • Calyx: There are usually 5 sepals, though they vary from 3-7.they may be free or united. • Corolla: There are as many petals as sepals. The corolla is sometimes absent. it may be free or connate. • Androecium: There are 10-15 stamens (the number of fertile stamens varies in many cases. They are free and inserted on an annular disc . • Gynoecium: These are usually (3-1) carpels and rarely 5 (syncarpous).The ovary is superior or some times inferior .it is often 1-celled (rarely 2-5 celled)and has one ovule in each chamber .often only one ovule matures in to a seed. • Seed: The seed is exalbumenous with a large curved embryo. Eg mango, cashew tree. Anacardium occidentale, cashew 40 Mangifera indica, mango 8.4 Family Sterculiaceae • Habit: These are shrubs or trees rarely herbs. • Leaves: leaves and stipules are like those of Malvaceae. • Flowers: The flowers are often regular and zygomorphic. They are bisexual, rarely unisexual and hypogynous. • Calyx and corolla: These are like those of malvaceae, sometimes corolla is absent. There is no epicalyx. • Androecium: The number of stamen varies from 5-25 though they are usually ∞ stamens. They are mostly arranged in two whorls the outer whorls opposite to d sepal and often reduced to staminodes or absent and the inner whorl opposite to the petals, being fertile and often branched all stamens is more or less united below into a tube or sometimes on the gonophore. The anthers are 2 locular. • Gynoecium: There are (5-2) carpel (often 5),syncarpous. The ovary is superior and in 5- to 2- locular, with 2- anatropous ovules in each loculus. The style is simple and the stigma lobed. • Fruit: The fruit can be dry or fleshy and is often a schizocarp. • Seed: This has a fleshy endosperm, sometimes arillate, example cola, cocoa tree. 41 WEEK 9 Technique for collecting and preserving common flora (HERBARIUM) Herbarium is a collection of dried, pressed, nicely preserved plant specimens arranged in sequence of an accepted system of classification. It is used for identification of fresh specimens, comparison between floras of different regions. The value of a herbarium depends on the care with which specimens were preserved and mounted, accuracy and completeness of identification and labeling and maintenance so that they do not deteriorate and can easily be referred to. Equipment for collection and collecting methods. 1. Specimens that have both flowers and fruits are selected. 2. Digger / trowel – for digging out the underground parts of the plants example Rhizome, corm, tubers etc. These parts help in identification and classification of the plant. 3. Pruning knife/bent sickle:- These have to be sharp. Pruning knife is used for cutting branches of herbs, shrubs and trees. Bent sickle has a long handle and is used for collecting flowers/fruits from high trees. 4. Vasculum/plastic bags:- Vasculum is an oval metallic container with screwed fasteners to keep it airtight to avoid wilting. Plastic bags can also be sued as they prevent loss of moisture when close tightly. 5. Field note Book:- This is a pocket sized note book used to record all information concerning the plant: These include a. Location e.g. country, province, Stale Park, river. Etc b. Habitat example river bank, forest edge, open field, swamp etc c. Field observation of the plant example height flower, colour, fruit colour, odour. d. Nature of stem juice example milky colour sticky, red, clear sap, thick, watery e. Collection number example 1 . . . . . followed by your last name 42 f. Date of collection g. Name of plant if know name could be local, common or botanical h. Association with other plants and its abundance. 9.1 Plant Press This consists of equal sized top and bottom frames measuring 30cm x 45cm made of these, light, strong pieces of plywood or metal. Between the frames are the folders, blotters and ventilators. Folders are old newspapers in which the collector places the specimens. Blotters absorb moisture from the specimens while ventilators provide air for drying. The press is tightly bound together by strong straps of canvas or leather and is placed in the hot sun or suspended over moderate heat. 9.2 Plant Pressing Plants for pressing should be placed in the folders in a manner so as to give maximum possible natural look. Longer specimens are bent into a V or W shape so as to fit them on a standard sized mounting sheet (30 x 45cm). Leaves, flowers parts should not be crouded. Thick organs may be trimmed and cotton paid placed proper pressing. 9.3 Mounting of pressed specimens: The pressed, dried specimen are glued or gummed to a hard standard sheet of paper. The paper should be fairly heavy to reduce. Flexing when mounted specimen are picked up. 9.4 Label Label is an important part of finished but usually 6 x 10cm. they are pasted with glue on the lower right hand corner of the mounting sheet. A label should contain the following information’s. 43 1. Region of collection accompanied by name of the institution. 2. Botanical name of the plant with the author citation 3. Locality of the collection 4. The habitat 5. Name of the collector and his field number 6. Collector field observation 7. Date of collection and the name of the person who identified the specimen. 9.5 Filling This is the arrangement of specimens in a herbarium. Specimen are filed according to a particular system of plant classification filling is done alphabetically for genera or according to phylogenetic sequence (in major herbaria). Specimens belonging to are genus are placed within a genus cover. In many major herbaria, the scheme of technicolour folder is in usage. The colour of the folder is indicative of the distribution of the plant. 9.6 Care of specimens Herbaria in warm and moist regions appear to face pest problems. The common pest adults and larvae of tobacco beetle (Lasioderma serricorne) and drug store beetle (Stegobium paniceus). These are controlled in the following ways: 1. Use of insecticides example Dichlorodiphenyl) trichloroethane (DDT), carbon disulphide and cyanide gas. 2. Specimens are poisoned with 10% aqueous solution of mercuric chloride 44 3. Use of insect repellants example Naphthalene balls and Para dichlorobenzene mixed in the ratio 2:1 and put in herbarium case. 4. Use of calcium chloride in small bottles the mouth covered with lose cotton and kept in herbarium cases to absorb moisture thereby preventing fungal attacks. 5. Specimen should be handled with care to avoid cracking and crumbing, tear and wear 6. Store specimens in steel cabinets and fire – proof buildings 9.7 Uses of Herbarium 1. The vegetation in any particular region is easily known. 2. While exploring a new area, the herbaria of previously explored areas can be referred to 3. Data about the nature, distribution and ecology of any plant of economic or medicinal value can be obtained easily. 4. It can serve as the basis for other branches of botany example plant ecology. Phytogeography, Economic botany e.t.c 45 WEEK 10 General classification of the Animal Kingdom Members are all multicellular and exist either in water or on land. The animal kingdom is divided into two major groups Group – invertebrata and Group – vertebrata. The invertebrates comprises of animals that do not passes backbone while the vertebrate animals are those that posses backbone The group invertebrate comprises of the following phyla: Phylum: coelenterata Phylum: Platyhelminthes Phylum: Nematoda Phylum: Annelida Phylum: Arthropoda Phylum: Mollusca 10.1 Group – Craniata (vertebrata) This forms the major part of the phylum chordata General Characteristics of vertebrata - Possession of an enlarged brain that is enclosed in a brain case – cranium - A segmental spinal column of vertebrae that became the axial support of the body - Body comprises of a head, neck, trunk and tail - Show a progressive series of structural and functional advances in all organ systems. Other characteristics include 46 1. Body covering is a stratified epithelium of epidermis and dermis with many mucous glands in aquatic animals. Most fishes are covered with protective scales in land dwellers, the exterior is confined with scales on reptiles, features on birds and hair on mammals. 2. The internal and jointed skeleton is of cartilage in lower vertebrates and of bane in higher groups. This support and protects various organs 3. Muscles are attached to the skeleton that makes movement possible 4. Complete digestive tract that is ventral to the vertebral column 5. Circulatory system of a well developed muscular heart of two, three or four chambers 6. Respiration in lower forms is by paired gills while terrestrial forms have lungs 7. Paired excretory organism – kidney. In lower form, it is segmental in nature and drain waste both from the coelom and the blood. In higher forms, it is non segmental and drain only from the blood. 8. Series of endocrine glands that secrete hormones for regulation of body processes. 9. With rare exceptions, sexes are separate The group vertebrata comprises of the phylum chordata with the following major classes Pisces (Fish), Amphibian (Amphibians) Reptilia (Reptiles), Aves (Birds) and Mammalia (mammals) 47 10.2 Group invertebrata Phylum Cnidaria Characteristics of the phylum: Cnidaria or coelenterata - Tissue grade of organization - Simple aquatic animals, mostly marine with few fresh water forms example Hydra. - Radially or biradially symmetrical with a central gastrovasculer cavity that opens to the exterior as the mouth - Only one opening i.e mouth with no anus - Diploblastic, outer layer called ectoderm and an inner layer of endoderm separated by a non cellular, gelatinous mass called MESOGLOEA. - Fairly small animals but often fund joined together to form colonies, units being termed Z00IDS - Possess nematocyst used for paralyzing prey or holding it. - Mouth surrounded by tentacles - No circulatory, respiratory or excretory organs. - No coelomic cavity - Nerve system of one or more net work of nerve cells but no central nervous system - Exhibit polymorphism i.e two main types of structures, the polyp and MEDUSA. Polyp is sessile and is the asexual form of zooid while medusa is free swimming and is the sexual zooid - Reproduction is both asexual and sexual. Asexual is by budding and sexual occurs by means of sperm and ova. - Egg usually develops into a ciliated free swimming larva known as PLANULA e.g Hydra, obelia, physalia, jellyfish and sea animal This phylum consists of three main classes 48 Class: Hydrozoa - Solitary or colonial - Asexual polyp and sexual medusae present medusae with a velum. Freshwater from include Hydra. Marine mostly e.g obelia, physalia Class: Scyphozoa - Solitary - Polyp stage reduced or absent - Bell shaped medusa without a velum - All are marine. e.g Jellyfish (Aurelia aurita). Class: Anthozoa - Solitary or colonial - Exclusively marine forms - All polyps, no medusoid stage - Found attached to stones, seaweed or should e.g sea anemone (Tealia crassicornis) Corals (Meandrina Cerebriformis) - Small solitary polyp living in fresh water size is 10 – 30mm. Body is cylindrical tube with lower and classes to form based disc or fort used for attaching objects and locomotion. The opposite and free oral end contain mouth on a conical hypostome encircled by 6 – 10 slender tentacles. Mouth leads into a digestive cavity or gastrovasculer cavity or interact. Nematocysts are found throughout the epidermis especially on the tentacles. 49 The side of the body may bear lateral buds that give rise to new individual by asexual reproduction. At times, it beers other rounded projections, the ovaries or tests concerned with sexual reproduction 10.3 Phylum Platyhelminthes (flat worms) General characteristics - Bilaterally symmetrical. - Dorsoventraly compressed (flattened). - Non segmented worms - Acoelomate, triploblastic animals - A system of flame cells and excretory vessels is present - No blood vascular system. - Hermaphrodite - Many are free-living but others are parasitic on or in the bodies of larger animals - Single opening to the alimentary canal i.e the mouth - Great power of regeneration There are three main classes. Class: Turbellaria –entirely free living Class: Trematoda (entirely parasitic) Class: cestoda (entirely parasitic) Example: planaria, fasciola, taenia, schistosoma External features of Planaria These are small creatures with flattened leaf-like bodies. Black in colour, up to 15mm long. Body is broad in front than at the back Where it roundly tapered and became extremely flattened. Has a definite front end, upper dorsal surface and lower ventral surface which is applied to the 50 substratum. Eyes are found near the anterior end. Mouth is at the ventral surface and of the only opening to the gut. 10.4 External features of Fasciola hepatica Diagram Leaf like structure. Adult has a flattened, oval shaped structure 2.5cm long and 1.2 – 1.3cm wide. Anterior region has a triangular projection at the apex – main and is surrounded by oral sucker. Ventrally at the base of the projection is a rounded ventral sucker. Between the two suckers is a shallow depression genital atrium. Posteriorly is a minute, terminal excretory pore. Body is covered by a tough cuticle. Mouth leads into a short buccal cavity followed by muscular pharynx and a narrow oesophagus which fork into two blind branches leading to posterior region and given off numerous lobed caeca. 10.5 Phylum Nematoda (Round Worms) - Bilaterally symmetrical, Triploblastic - Unsegmented, pseudocoelomates - Cylindrical but tapering at the anterior and posterior ends. - Uniform in structure although differ in size and habitat. - Can be found in terrestrial, freshwater, marine or parasitic habitats. - Lack suckers mouth is surrounded by Lips or papillae - All are dioecious (separate sexes - Alimentary cannot is a straight complete tube with two openings, mouth and anus. - Species parasitic in man vary in size from threadlike object just visible to the naked eye (sronglyloides) to elongated string-like worms attaining a length of 60cm (Dracunculus) - Have internal fertilization, - Females are either viviparous (produce larva) or oviparous (lay eggs). 51 - Moult usually four moult during development from ovum to adult and third stage larva is responsible for infection of a new host. - Nematodes which infect human live in the tissues or intestinal tract. Tissue nematodes are transmitted by insect vector only while intestinal nematodes are soil transmitted Nematodes are divided into two main groups based on phasmids (caudal sensory structure) 1. Class:- Aphasmida Members lack phasmids. Male has one spicules example, Trichuris trichiura (whipworm) in soil, Trichinella spiralis (fund in undercooked or raw meat, 2. Class: Phasmids: Members have phasmids, male has two spicules example, Ancylostoma duodenale (hookworm) Dracunculus medinensis (Guinea worm) Ascaris Lumbricoides) (roundworm Structure of T. Spiralis Small cylindrical worm pointed anteriorly and rounded posteriorly, female is 3mm long and 80cm wide, male is 1.5mm long and 40.cm wide Structure of Ascaris lumbricoides - Large worm, body is relatively stout although it tapers at each end particularly at the hinder end. In male, the tail end curves sharply towards the ventral surface, shows a pair of blister (copulatory spicules) protruding from the cloaca which is situated a centimeter from the tip of the tail. Three lips guard the entrance of the mouth. Body is encased in a tough but smooth cuticle which is semitransparent so that some of the internal organs are seen through it. 52 10.6 Phylum Annelida (Ringed Animals) General Characteristics - Triploblastic, elongated cylindrical body - True segmented worms - Metameric segmentation - Perivisceral coelom is present. - Body wall very muscular and have an inner layer of an outer layer of circular muscles - Nervous system well developed - Excretory system consist of tubes called nephredia - Body covered by thin cuticle with setae - Some live in sea, soil or parasitic - Closed blood system, digestion is extra cellular - Larva when present is trochophore e.g earthworm, leeches, and nereis. There are three main classes Class: Polychaeta - Largest class of annelids - Mostly marine with few found in brackish water, freshwater and moist soil. - Same free living, same tube living and same burrows into mud. - Have well marked internal and external segmentation - Each body segment bears a pair of appendages called parapodia which bears numerous chaetae - Many reach up to a length of 1m. - Cephalisation is well pronounced. - Well defined head region with eye and tentacles 53 - Parapodium used for locomotion assisted by chaetae - Sexes separate No permanent gonads - Fertilisation is external with a free swimming trochophore larva, Example Nereis diversicolar (rag worm) Arenicola (Lugworm) Chaetopterus (tube living worm) Diagram of Nereis Class: Oligochaeta - Terrestrial or freshwater habitat. - Well marked external and internal segmentation - Posses few chaetae e. No parapodium - Hermaphrodite, cross fertilization - Clitellum present at sexual maturity - Eggs are deposited in cocoon. - No free larval stage - Respiration over the entire body surface example earthworm, tubifex Diagram of Earthworm 54 Class: Hirudinea - Vermiform, dorsoventraly flattened - Body consist of definite number of segment marked externally by secondary rings and annuli - Capable of elongation and contraction to different proportion - Feed by sucking in organic matter using pharynx or may be parasitic by sucking blood of mammals, frog/tadpoles and small fishes - Found in ponds, swamps and slow flowing streams - Hermaphrodite - Lack setae and parapodium. example Hirudo medicinalis Diagram of Hirudo medicinalis 10.7 phylum: Arthropoda (Jointed limbs) In terms of number of species and individuals, this phylum surpass any other phylum. Of some 1 ¼ million known animal species, 4/5 are arthropods. Also this phylum contain the class insecta which represent almost ¾ of described animal species. General Characteristics of this Phylum • Triploblastic • Bilaterally symmetrical • Metamerically segmented • Paired jointed appendages on each metamere with at least one pair acting as a set of jaws. • Reduced coelomic cavities and a major body cavity – Haemocoel with fluid called Haemolymph. • Presence of a skeletal covering composed of chitin. This forms the exoskeleton. 55 • Nervous system with cerebral ganglionic mass connected to ventral paired ganglia • Open circulation with no blood vessels • Anterior photoreceptors • Moult and metamorphosed between immature and adult stage during growth • Sexes separate • Can be found almost in every environment including aerial one Classification There is no definite system of classification for the phylum existing in view of divergent ideas concerning the phylogeny of arthropods. It is in a state of flux and may always remain. Divided into four subphyla 1. Subphylum – Trilobita (extinct) 2. Subphylum – Chelicerata consisting of the class: Arachnida, Merostomate and Pycnogonida 3. Subphylum – Crustacean 4. Subphylum – Uniramia consisting of the classes Insecta Myriapoda Chilopoda Symphyla Diplopoda Pauropoda 56 Subphylum – Chelicerata Absence of antenna, presence of a pair of chelate appendages as the first pair of segmental appendages Class – Merostomata Characteristics • Aquatic, usually marine with brachial respiration • Body divided into two – prosoma and opisthosoma Prosoma has chelicerae on the first segment and 5 similar pairs of appendages on the 2nd – 6th segments. The opisthosoma is divided into a Mesosoma with 5 or 6 pairs of lamilli form appendages of which the 1st form a genital operculum while others are biramous and bears gills and a Metasoma without appendages and with a telson. E.g. Horseshoe crab Class: Arachnida e.g. – spiders, scorpion, harvest man General Characteristics • Body divided into two parts anterior prosoma (cephalothorax) bearing six pair bears the chelicerae that is associated with the mouth (pre oral) second pairs bears the pedipalps (post oral). The remaining four pairs are legs. Posterior opisthosoma makes up the abdomen. The genital opening is on the anterior part of the opisthosoma. The only appendages here are the pectines of scorpions and spinnerets of spiders • Respiration is by lung books and or tracheae. • Development is straight forward without metamorphosis 57 • Generally terrestrial Subphylum – Crustacean e.g. crabs, shrimps, lobsters, woodlice Characteristics • Aquatic with majority occurring in marine environment • Exhibit tremendous morphological diversity • Include the largest arthropods, the crabs and lobsters as well as the smallest tiny water fleas and shrimps. • Five of the six head segments bears appendages • Two pairs of sensory antennae and three pairs of mouth parts • The remaining segment is divided into two region, thorax and abdomen terminated by a post segment region telson • The thoracic segment fused with head to form the cephalothorax while a backward fold of head forms the carapace • Sexes are separate and often display sexual dimorphism but few are hermaphrodite • Reproduction is by sexual means but parthenogenesis also occur • Very plentiful is sea therefore termed marine insects. Subphylum – Uniramia Class – insecta e.g. grasshopper, cockroach, ant, fly General characteristics • Most extensive class in the animal kingdom • The number of described species exceeds the number of all other known animal species • Invade all habitable terrestrial environment • Body divided into three regions – head, thorax and abdomen 58 • Head bears six segments, a pair of antenna, three pairs of mouth parts, mandibles, first and second maxillae • Thorax bears three segments and each segment bears a pair of appendages (legs), second and third segments bears wings if present • Abdomen bears eleven segment and posterior telson • Anus opens at the posterior end of the abdomen and just anterior to it are the genital aperture that opens ventrally • Appendage at the eleventh segment is the Cerci • Respiration by direct diffusion of gases • Undergo metamorphosis during development • Depending on feeding habit, mouth part can be modified into sucking, piercing or chewing type. Class: Myriapoda Characteristics • Body consist of head followed by numerous similar segments • Series of similar legs bearing segment • Single pair of antennal • One or two pairs of maxillae behind mandibles • Mostly terrestrial • Include the centipedes and millipedes 10.9 Phylum: Mollusca General Characteristics Second only to arthropods in terms of abundance - Display a belvildening diversity in form despite sanitarily in basic morphology - Range in size from minute of few mm (half mm) snails to giant squids which is over 15m long exclusive of tentacles that is 6m in circumference 59 and weighing 2 – 3 tonnes. Includes the small flattened chitins which creep about on rocks of sea share, staggering variety of bivalves, snails slugs and peculiar borrowing tooth shell of sandy of muddy substratum. The most highly evolved are the predatory cephalopods (Octopus, squids and cuttlefish). - Wide spread in aquatic and terrestrial habitat. - Triploblastic - Coelomate animals which do not show segmentation, soft bodied and bilaterally symmetrical - Body consist of head, with tentacles flat creeping foot and dame like visceral hump containing most of the alimentary canal, digestive gland, gonads, heart, kidney and paired gills called ctenidia. The skin of the visceral hump is called the mantle which grows downward posteriorly to cover a cavity called mantle cavity into which opens the anus, the excretory and reproductive duct. The mantle secretes the shell. - Sometimes a larval form which resembles the trochophore larva of annelids - Of interest to man as food, as source of dyes, intermediate host to many important parasitic helminthes, destructive barer and producers of pearls, shells use extensively for bolluns ornament, for shell collection - Moth is interiorly while anus is posteriorly located Six main classes 1. Class: Monoplacophora 2. Class: Amphineura 3. Class: Scaphopoda 4. Class: Gastropoda 60 5. Class: Bivalvia or lamellibranchiata 6. Class: Cephalopoda Class: Monoplacophora – mainly fossil molluscs Only one living genus neopilina with four known species. Have limpet – like appearance lives in the depth of the ocean. Shell of neopilina is uncoiled. There is a simple foot used for creeping. Gills, kidneys, coelomic sacs and contain muscles are serially repeated. Class: Amphineura Constitute a small class of marine mollusks Represented by several genera and species of chitins, all of which hare small, sluggish creatures found in rock crevices or clinging to the undersides of stones. Possess a dorsal shell made up of longitudinal raw of eight plates. The head foot has a broad creeping sole but the head – foot has a broad creeping sole but the head is inconspicuous and devoid of tentacles or eyes. The mouth is at the anterior end of the head and the anus at the extreme posterior end of the body. Bilaterally symmetrical. Class: Scaphopoda These are small group of burrowing marine mollusks known as the tusk – shells with a hollow that opens at both ends within which is an elongated body with a short extensible foot used mainly for burrowing into the sandy deposits of which the animal live. Ranges in length usually from about 2 – 5cm. The head bears bunches of slender tentacles used for catching food. The largest living species is Dentalium vernei which is about 13cm long and a diameter of 1.5cm. 61 Class: Gastropoda Constitutes the largest and most diverse group of the Mollusca with about 40,000 living species and more than 15,000 fossil species. Predominantly marine group, however widely spread in fresh water habitats. One large sub class pulmanata has become typically terrestrial. Body consist of a ventrally well developed head and a broad muscular foot both which retain a bilateral symmetry. Exhibit unusual features not found in any other class of mollusk. They are coiling and torsion. Torsion is usually an early larval evend, coiling occurs at a later phase in development e.g. periwinkles, topshells, limpets, sea snails, slugs, land snails e.t.c. Class: Bivalvia - Mainly marine which burrow in sand and mud but same have colonized the fresh water with no terrestrial forms. - Second largest class of mollusca - Bilaterally symmetrical, laterally compressed with extensive lateral mantle lobes which secrete a single shell of two valves and a ligament which joins them dorsally at a hinge. Head is rudimentary. Ciliary feeders, the foot is compressed and adapted for burrowing. Fertilization is external E.g. mussels, scallops, oysters, clams, cockles Class: Cephalopoda - All are active predaceous creatures able to swim and capture large crustacean such as crabs 62 - Body is characterized by a fore – shortening of the anterior – posterior axis and an extension of the dorso–ventral axis - Head well developed and bears a pair of highly developed eyes and a number of tentacles. Foot is represented by a siphonal apparatus that assist in swimming. Some have ink sac (cuticle fish) - Sense organs are highly developed. Shell occur with the exception of Nautilus where it encloses the body is reduced and internal and in octopuses it is absent. e.g. squid, pearly Nautilus, Octopus, cuticle fish 63 WEEK 11 Phylum chordata General characteristics - Largest and ecological mort important phylum in line of evolution. - It is distributed in all habitats- marine fresh water and terrestrial. - Include all the large animals present on earth today with the possible exception of the cephalopods. - Possession of a notochord at least sometimes or another during their bicycle. It may persist throughout life example lancelet, lamprey or be replaced either wholly or partially in the adult animal by a backbone example fishes reptiles, birds and mammals - Pharyngeal region has in its lateral walls a series of paired openings (gill slits) communication with the exterior to form visceral cleft in aquatic forms, it becomes modified to provide respiratory survey aces as gills or brachial clefts. - Central nervous system is always dorsal in position, hollow and tubular in structure. The anterior end of the cord is usually enlarged to form brain. - Bilaterally symmetrical with three germ layers and a segmented body marked externally. - Circulation of blood in blood vascular system in maintains by a central muscular propulsive organ-heart that is ventral (closed circulation) except urochordata - Post and tail usually projecting beyond the anus which is extremely flexible and muscular. In aquatic forms, it constitute the main propulsive organ. In terrestrial firm, it may be reduced in the adult. - Complete digestive system. - Cartilaginous or bony endoskeleton formed in mesoderm. - Exoskeleton often present, well developed in fishers, reptiles and birds 64 - Sexes usually separate (few hermaphrodite or protandric) oviparous or viviparous The major classes of this phylum which comprises of the vertebrate include Class – Pisces (fishes) Class – Amphibia (Amphibians) Class – Reptilia (Reptiles) Class – Aves (Birds) Class – Mammalia (Mammals) Class Pisces General characteristics - Cold Blooded (poikilothermic) - Aquatic, either fresh water or marine - Skin covered with scales - Body streamlined - Presence of paired and unpaired fins supported by soft or spiny ray - Dorsal, caudal and anal fins are unpaired while the pectorals and pelvics are paired - Endoskeleton by gills, opens to the outside by gill-slits - Gill slits are never more than seven pains usually five pains are present - Swim bladder or airbladder usually present - Lateral line well developed - Heart is venous and two chambered 65 Diagram Tilapia 66 WEEK 12 Class Amphibia General Characteristics - Skin moist and glandular, no external scales - Two pairs of limbs for walking or swimming .No fins, toes four to five or fewer. - Nostrils two, connected to mouth cavity, eyes often with movable lids, ear-drums, external on toads and frogs. Mouth usually with small teeth, tongue often protrusible - Skeleton largely bony, skull with two occipital condyles. Ribs if present not attached to sternum - Hearth typically three chambered - Respiration by gills, lungs, skin or mouth lining separately or in combination - Body temperature variable - Excretion b y mesonephric kidneys - Fertilisation external or internal mostly oviparous usually an aquatic larva firm with metamorphosis to adult form. Diagram of Frog 67 Class: Reptilia Genera Characteristic - Body covered with dry cornified skin usually with ectodermal scales - Limbs provided usually with five toes and adapted for climbing, running or paddling. Absent in some lizards and snakes - Skeleton well ossified - Respiration by lungs and gills, cloacal respiration is some aquatic turtles - Heart incompletely 4 chambered - Body temperature variable - Excretion by metanephric kidneys - Sexes separate, fertilization internal - Amniotic eggs covered with calcareous or leathery shells e.g Lizard, crocodile. Snakes and turtle Diagram of Lizard Class – Aves (birds) Characteristics - Body spindle shaped with four division – head, neck, trunk and tail 68 - Body covered with feathers - Two pairs of limbs, forelimbs modified as wings for flight, hind limbs adapted for perching, walking or swimming (with lobes or webs) - Skeleton light, strong, fully ossified with air sacs. Many bones fused, providing rigidity - Upper and lower jaws drawn in front to form beak or bill with horny sheath. No teeth. - Skull with are occipital candyle - Neck usually long and flexible - Respiration by compact highly efficient lungs attached to ribs and connected to thin walled air sac - Voice boxes at base of trachea. - Body temperature constant - Excretion by metanephric kidneys. Fertilization internal, female with only left ovary and oviduct. - Young at hatching cared by parent Diagram of a bird 69 Class Mammalia - Body covered with hair but reduced in some. Skin with many glands (sebaceous, sweat, scent and mammary) - Skeletal features of the skull with two occipital condyles seven cervical vertebras and often an elongated tail - Mouth with teeth on both jaws - Movable eyelids and fleshy external ears (pinked) - Fore limbs (reduced or absent in same) adapted for many forms of locomotion - Four chambered heart, persistent left aorta - Respiratory system of lungs and voice box. - Muscular partition (DIAPHRAGM) between thorax and abdomen - Excretory system of metanephric kidneys with ureters that opens into a bladder - Nervous system of well developed brain and twelf pains of cranial nerves - Sexes separate Reproductive organ vagina. - Internal fertilization. Eggs develop in a uterus with placental attachment. - Young nourished by milk from mammary glands with exception of Duckbilled platypus and spiny anteaters that lay eggs and do not possess true mammary glands 70 WEEK 13 External Features of a Tilapia It is found in aquatic environment (fresh water) Bony fish, spindle shaped, flattened laterally to give it a streamlined shape that allows it to move smoothly through the water. Body is covered with scales with paired and unpaired fins. Unpaired fins are the dorsal, ventral and tail fins while the pairs fins are the pectoral and pelvic fins. Diagram of tilapia External Features of Frog The skin of frog is soft, smooth and moist. The head bears a wide mouth, small valvular nostrils, large spherical eyes and behind each eye are flat eardrum or tympanic membrane. Each eye has a fleshy, opaque upper eye lid and a lesser lower lid. Continuous with the latter and folded behind it when at rest is a transparent portion which functionally resembles the nictating membrane of higher vertebrates. At the posterior end of the body is the vent or cloacae opening through which are discharged undigested food wastes, urine and eggs or sperm. At mid body is the sacral hump, where the pelvic girdle is hinged to the sacrum. The short front led (arm) comprises of an upper arm, fore arm, wrist and hand with 4 digits and vestigial thumb. The inner digit (thumb) is thickened on males especially in the breeding season. The hind leg includes a thigh, lower leg, ankle and long foot with a narrow sole 71 and five slender toes connected by broad thin webs. The palm and soles bear cornified tubercles that protect the feet against abrasion and provide traction on wet, slippery surfaces. Diagram of a frog External Features of a Lizard Body is made up of a head and trunk joined together by a definite neck. The trunk ends in a long tapering tail. On the head, there is a wide terminal mouth, a pair of nostrils, a pair of slightly protruding eyes with movable eye lids and a pair of ear drums found in shallow depression on the skin. Below the eardrum is a fold of skin, the gular fold which is lowered during courtship or when the animal is frightened. Above the neck is a median crest of skin, the nuchal crest, which the male raises when fighting with each other. The trunk bears a pair of fore and hind limbs which terminate each in five clawed digits on the underside. Just behind the hind limbs is a transverse slit, the cloaca. In the male, there is a hemi cod at each end of the cloaca. The whole body is covered by overlapping scales. Adult males are larger and more brightly coloured than females when are smaller and dull coloured 72 Diagram of a lizard External Features of a Domestic Fowl Has distinct head, long flexible neck, a stout spindle shaped body (trunk). The two fore limbs are attached high on the back and have long flight features. Wings folded in Z shape when at rest. On each hind limbs, the two upper segment are muscular. The slender lower leg contain tendons but little muscles and is covered with cornified scales, and four toes that ends in horny claws. The short tail bears a fanlike group of long tail feathers mouth is extended as a pointed bill with horny covering. On the upper mandible are two slit like nostrils. Eyes are large and lateral. Each with upper and lower eye lids. Below these is the nictating membrane which can be drawn independently across the eye ball from the anterior corner. Below and behind each eye is an ear opening hidden under special feathers. There is a fleshy median comb and lateral wattles on the head. Below the base of the tail is the vent. 73 Diagram of a Bird External Features of a Rabbit Body consist of the head, neck, truck and the tail and is covered with fur Head bears a terminal mouth which is bordered by a pair of upper and lower lips. The upper lip has a slit or cleft in the centre exposing the incisor teeth in front. Above the mouth lies a pair of nostrils. The eyes have an upper and lower eye lids and a nictating membrane. In rabbit, the senses of smell and sight are well developed. At the sides of the mouth on the upper lip are whiskers or vibrissae which are sensitive to touch. These help the rabbit to move in its dark burrow. It has a pair of external ears that consist of a funnel like pinna. The narrow neck connects the head to the trunk. The trunk bear two pairs of limbs and end in a short tail is made up of two regions, the thorax and the abdomen which hare separated by a muscular sheet, the diaphragm. Within these two regions lie the internal organs or viscera. On the ventral side of the abdomen, the adult female has three to five pairs of teats which bear the openings to the mammary gland. The anus lies under the tail while the urinogenital opening is just ventral to it. On either side of the tail is a hairless patch of skin into which opens perineal gland. The secretion from this gland gives the rabbit it characteristic smell. Each fore limb consists of the upper arm, fore arm and fore foot with five digits. Each hind limb consists of the thigh, the shank and the hind foot with four digits. The hind limbs are longer than the fore limbs and are much more powerful. Their straightening results in the forward thrust necessary for jumping. 74 Diagram of rabbit 75 WEEK 14 Protochordates as a link between invertebrates and vertebrates The protochordates (urochordata and cephalochordata) are considered to be link between vertebrata and invertebrate. The protochordates shows lots of embryonic affinities with vertebrata and invertebrate. The cephalochordates possess all the four chordate hall marks (notochord, dorsal tubular nerve cord, pharyngeal gill slits and post anal tail). But its notochord is over developed into a forward extension for its specialized burrowing mode of life. It effectively prevent the development of a proper brain its kidney type bear little resemblance to the vertebrate glomerular tubular nephron and there is a non vertebrate like proliferation of gill slits. The adult ascidians (Tunicates) are virtually immobile forms surrounded by a tough cellulose containing tunic of variable colour. Their adult life is spent in one spot attached to same submarine surface filtering vast amounts of sea water from which they extract their plank tonic food. As adult, they lack notochord tubular nerve cord, post anal tail, sense organs and segmental musculature superficially, they resemble sponges (invertebrate) for mere then they resemble the vertebrates. Acorn Worm, common name for simple, wormlike marine animals in the hemichordate phylum. They are of special interest because of their close relationship to chordates. This connection is evident in the adult anatomy. Some representative acorn worms have gill slits, traces of a supporting structure resembling a notochord, and a tubular nerve cord, which are features characteristic of vertebrates. The larval stages of acorn worms, however, are very much like those of echinoderms such as starfish, indicating a remote common ancestry of echinoderms and vertebrates. The hemichordates are divided into two classes comprising about 50 species. The first class, the acorn worms, consists of animals that average 10 cm (4 in) in length, although some species may be up to 1.5 m (up to 5 ft) long. They construct burrows, commonly U-shaped, in sand of shallow seafloors using an 76 extendable, muscular proboscis attached to a thick collar that resembles an acorn—hence the name. They secrete a slime that collects food particles on the proboscis and collar, but some species filter sediments and sand through a complicated pharynx with many gill slits. The second class consists of small, usually colonial animals of the deep sea. They are not worm-shaped but stout, and they usually construct tubes. Food is captured by tentacles that project from the tube. The body is much simplified, and gill slits are reduced to one pair or none. Diagram of an Acorn Worm 77 WEEK 15 Preservation methods of common vertebrates and invertebrates Preservation is a method of keeping animal tissues as closely as it is while living. The specimens will last for longer time, can be stored indefinitely by destroying any bacteria, fungi that could degrade the specimen and protect from further action by microorganisms. A preservative is a chemical compound that is capable of keeping the animal tissues as closely as it is while living. The procedure for preserving animal specimen varies greatly from one animal group to another. In most cases, the specimen must first be killed or narcotized in such away as to leave the tissue relaxed and suitable for display. The material is then fixed in this condition and then finally preserved. The final preservation is normally made either is a solution of ethanol and methanol usually known as alcoholic or in a solution of methanol formaldehyde known as formalin for preservation purpose. Industrial methylated spirit diluted to an appropriate concentration can also be used satisfactorily. Appropriate killing, narcotizing, fixing and preservation of various animal groups are as follows: Animal Group Killing or Agent Fixative Preservative Notes - Best Narcotizing A. Protozoa - - stained preserved in smears on slides Porifera 70% alcohol 70% alcohol 70% alcohol Change the alcohol after 24 hours. Sponges can also be preserved dry. 78 Coelenterates Hot Bouins Bouin’s solution 70% alcohol solution Flood live specimen with hot Bouin’s solution starting at base moving up to the tentacles Platyhelminthes 2 – 4% methanol 2 – 4% 2% methanol Allow (cestodes) or formal acetic methanol or acid alcohol specimen to 70% relax in cold water and then wrapped on a supported then fix Nematodes Hot 2% Hot 2% 2% methanol Larger forms may be methanol or hot methanol 70% alcohol or or 70% dropped directly into hot alcohol the hot fixative 70% alcohol Annelids (leaches Methanol crystal 2 – 4% 70 and or MgSO4 methanol – 90% Place alcohol earth worms) worms shallow sufficient in dish a with water to cover them. Add little alcohol, crystals menthol or MgSO4 every 2 minutes till the worms are limp and insensitive to touch transfer to fixative and leave over night, then transfer to alcohol Mollusks (snails) Epson salts or 2 – 4% 70% alcohol Place snail in a stopper asphyxiation methanol or methanol 2% jar completely filled with H2O and leave for 79 24 hours or may be placed in warm H2O, allow to expand before slowly adding Epson salt. Transfer to fixative for 24 hrs and then to preservative Crustaceans 2% methanol small fresh water and 2% 70 – 90% Add sufficient formalin methanol alcohol to marine specimen in its habitat water to form forms 2% methanol transfer to alcohol for preservation Insects juvenile all 70 – 80% 75 – 80% 75 forms alcohol alcohol – 80% Place insects in alcohol alcohol in small vials. Change except orthoptera alcohol after 24hrs. if and permanent slide is to isoptera be made add KOH is the preparation All other insects Killing juvenile bottle - or containing ethyl adults Dry mount on cards or ethanoate pins (acetone) naphthalene to add prevent attack by pests Other arthropods 70% alcohol 70% spiders, alcohol mites scorpions, ticks 70% alcohol Specimens should be dropped directly into the alcohol 80 Fish Formation 70% alcohol or 2% 2% Methanol or Place fish in large Methanol or vessel to which a little 70% 70% alcohol alcohol formalin added, has been when dead transfer to fixative or transfer directly in 70% alcohol Amphibians KOH methanol with 3 – 4% 2% methanol Place methanol or specimen in 2% KOH with methanol. Methanol or Allow to sink, relaxed 70% alcohol to the bottom then position and transfer to fixative. Or specimen may be placed in plastic bags in freezer for 24hrs thawed, positioned and fixed Reptiles Freezing 4% 3% methanol Place in a plastic bag in methanol a freezer and leave for 24 hrs and then allow to thaw place in 4% methanol and inject same of the fixative into body cavity. In case of large lizard it should be injected into each limbs and into base of tails. Birds - - Dry mounts 81 Mammals CO2 in a killing 3% chamber methanol 3% methanol After placing killing in a chamber, specimens should be left in the chamber for at least 10 minutes after collapse to ensure death has taken place. The body cavity and larger muscles should be injected fixatives 82 with
