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Unit VI Five kingdoms are currently used to categorize all organisms. The characteristics of each of these kingdoms, and important taxa (organisms classified into categories) within these kingdoms, are described below. Chapter 25 A) KINGDOM MONERA a) They are prokaryotes b) As prokaryotes they lack nuclei and the various organelles of eukaryotes. c) Possess a single “naked” chromosome consisting of a single DNA molecule without the proteins found in eukaryotes. d) Most of prokaryotes contain on the cell wall peptidoglycans. e) Another feature important in describing prokaryotes is their ability to survive in the presence or absence of oxygen. B) Mode of Nutrition they are organized by their mode of nutrition, that is, how they metabolize resources, as follows: a) Autrophs manufacture their own organic compounds. To do this, photoautotrophs use light energy and chemoautotrophs use energy obtained from inorganic substances. b) Heterotrophs must obtain their energy by consuming organic substances produced by autrophs. Some heterotrophic bacteria are parasites, obtain their energy from the living tissues of a host. Others are saprobes, obtaining their energy from dead decaying matter. Also called decomposers. C) Eubacteria ( true bacteria) and Archaebacteria are two distinct groups within the Monera. a) Archaebacteria are distinguished by these three major futures: 1.- Their cell walls lack peptidoglycans. 2.- Their ribosomes are more similar to ribosomes of eukaryotes than to those of eubacteria. 3.- Their plasma membranes contain lipids that differ from those found in the plasma membranes of all other organisms. b) There are three groups of archaebacteria, as follows: 1.- Methanogens are anaerobic, heterotrophic bacteria that produce methane (CH4). 2.- Extreme homophiles (salt lovers) live in environments with high concentrations of salt. They are found in salt lakes, such as he Great Salt Lake and the Dead Sea, or in salted food, where hey can cause spoilage. 3.- Moacidophiles ( heat and acid lover) live in hot (60◦ C to 80◦) and acid ( pH 2 to 4) environments. c) Various features are used to categorize the eubacteria , as follows: 1.- The principal means by which the eubacteria are categorized is by their mode of nutrition, or how they metabolize resources. 2.- Some eubacteria are distinguished by their ability to produce endospores, resistant bodies that contain the genetic material and a small amount of cytoplasm surrounded by a durable wall. 3.- Eubacteria are distinguished by their means of motility, whether by flagella, gliding, or corkscrew motion. When flagella are present, they can be apical or posterior, or they can completely cover the cell. 4.- Bacteria are classified onto one three shapes: cocci (spherical), bacilli (rod shaped), and spirilla (spirals). 5.- The cell wall distinguishes two broad groups of bacteria. d) Some of the more common groups of bacteria follow: 1) Cyanobacteria are photosynthetic, using chlorophyll a to capture light energy, splitting H2O, and O2 as do plants. 2) Chemosynthetic bacteria are autotrophs. 3) Nitrogen-fixing bacteria are heterotrophs that fix nitrogen. 4) Spirochetes are coiled bacteria that move with a corkscrew motions. Chapter 26 1.- KINGDOM PROTISTA A) Feature hared by two or more groups may represent convergent evolution; that is, the feature arose among the groups independently. Nevertheless, the grouping given below present this varied kingdom with a degree of organization that will help you remember them. a) Algaelike (or plant-like) members of the Protista all obtain energy photosynthesis. 1.- Euglenopyta, or euglenoids, have one to there flagella at their apical (leading) end. 2.- Dinoflagellata, or dinoflagellates, have two flagella. 3.- Chrysopyta, or golden algae, are golden yellow and have one two apical flagella. 4.-Bacillariophyta, or diatams, have tests (shells) that consist of silica (SiO2). 5.- Chlorophyta, or green algae, have both chlorophyll a and b, have in sexuality. 6.- Phaceophyta, or brown algae, are multicellular and have flagellated sperm cells. 7.- Rhodophyta, or red algae, contain red accessory pigments called phycobilis. B) Animal-like protests, are heterotrophs. Some important phyla follow: 1.- Rhzopoda are amoebas that move by extensions of their cell body called pseudopodia. 2.- Foraminifera, or forams, have tests usually made of calcium carbonate. 3.- Zoomastigophora, or zooflagellates, are flagellated protozoa. 4.- Sporozoa are parasites of animals. 5.-Ciliophora are distinguished by their cilia, which they use for moving and other functions. C) The fungus-like protists resemble fungi because they form either filaments or spore-bearing bodies similar to the fungi. 1.- Acrasiomycota, the cellular slime molds, exhibit both funguslike and protozoalike characteristic during their life cycle. 2.- Myxomycota, the plasmodial slime molds, grow as a single, spreading mass (or plasmodium) feeding on decaying vegetation. 3.- Oomycota include the water molds, downy mildews, and white rusts. Chapter 28 1.- KINGDOM FUNGI A) Fungi grow as filaments called hyphae (singular, hypha). Fungi are either parasites or saprobes, absorbing the breakdown products from the action of digestive enzymes that they secrete. Fungi are dominantly haploid, but most form temporary diploid structures for sexual reproduction. 1.- The fallowing stages occur during sexual reproduction a) Plasmogamy is the fusing of cells from two different fungal strains to produce a single cell with nuclei from both strains. b) Karyogamy is the fusing of the two haploid nuclei of a dikaryon to form a single diploid nucleus. c) Meiosis of the diploid nucleus restores the haploid condition. B) Fungi reproduce asexually by various means, including fragmentation (the breaking up of hyphae), budding (the pinching off of a small hyphal outgrowth), and asexual spores. 1.- Two kinds of asexual spores are described bellow: a) Sporangiospores are produce in saclike capsules called sporangia (singular, sporangium) that are each borne on stalk called a sporangiophore. b) Conidia (singular, conidium) are formed at the of specialized hyphae, not enclosed inside sacs. 2.- The fungi form three natural group based on sexual reproduction. a) Zygomycota lack septa, except when filaments border reproductive filaments b) Ascomycota have septa and reproduce sexually by producing haploid ascospores. c) Basidiomycota have septa reproduce a sexually by producing haploid basidiospores. d) Deuteromycota, or imperfect fungi, is an artificial group comprising fungi for which no sexual reproductive cycle has been observed. e) Lichens are mutualistic associations between fungi and algae. f) Mycorrhizae are mutualistic associations between fungi and roots of plants. Chapter 27 1.- KINGDOM PLANTAE A) In order to survive the transition from water to land, it was necessary for plants to make adaptations for obtaining water and to prevent its loss by desiccation (drying out). 1.- The following list summarizes the major plant adaptations for survival on land. a) Except for the primitive division Bryophta (mosses), the dominant generation of all plants is the diploid sporophyte generation. b)All plants possess a cuticle, a waxy covering on aerial parts that reduces desiccation. c) The development of a vascular system in plats further reduced their dependency on water. d) In the more primitive plant divisions, flagellated require water to swin to the eggs. e) In the most advanced division, the Anthophyta, the gametophytes are enclosed (and thus protected) inside an ovary. f) Plants of the Coniferophyta and Anthophyta have developed adaptations to seasonal variations in the availability of water and light. B) A list of the major plant divisions follows. Of particular importance is how each division shows an increasingly grater adapatation to survival on land. 1.- Bryophyta are the mosses, liverworts, and hornworts. Gametes are produced in protective structures called gametangia on the surface of the gametophytes, the dominant haploid stages of the life cycle of bryophytes. C) The following divisions of plants are informally categorized as tracheophytes, or vascular plants, because they posses xylem and phloem. 2.-Lycophyta include two groups of plants. 3.- Sphenophyta include extinct woody trees common during the Carboniferous period and extant herbaceous plants called horsetails. 4.- Pterophyta are the ferns. d) The next two plant divisions produce seeds. . The microsporangium produces numerous microspore mother cells, which divide by meiosis to produce four haploid cells, the microspores. . The megasporangium. Called the nucellus, produces a megaspore mother cells, which divides by meiosis to produce four haploid cells. . When a pollen grain contacts the megasporangium, the tube cell directs the growth of a pollen tube through the micropyle and toward the egg. 5.- Coniferophyta are the familiar conifer (literally, “conebearing”). They include pines, firs, spruces, junipers, redwoods, cedars, and others. The male and female reproductive structures are borne in pollen-bearing male cones and ovule-bearing female cones. 6.- Anthophyta, or angiosperms, consist of the flowering plants. Major plants of the flower are as follows: a) The carpel (or pistil) is the female reproductive structure and consists of three parts: an egg- bearing ovary, a style, and a stigma. b) The Stamen is the male reproductive structure and consist of a pollen-bearing anther and its stalk, the filaments. c) Petals, and sometimes sepals, function to attract pollinators. 1.- The flower is a major evolutionary advancement for the fallowing reasons: a) The flowering is a special adaptation to attract pollinators, such as insects and birds. b) The ovules are protected inside an ovary. c) The ovary develops into a fruit which fosters the dispersal of seeds by wind, insects, birds, mammals, and other animals. Chapter 29 1.- Kingdom Animalia A) The members share a number of characteristics, as follows: a) All animals are multicellular b) All animals are heterotrophic c) The dominant generation in the life cycle of animals is the diploid generation. d) Most animals are motile during at least some part of their life cycle. e) Most animals undergo a period of embryonic development during which two or three layers of tissues from. B) The diversity of animals originates from variations in the following characteristics: a) Tissue complexity. Most animals, collectively called the eumetazoa, have closely functioning cells organized into tissues. Two (diploblastic) or three (triploblastic) layers of tissue called germ layers may be present. b) Body symmetry. Animals have either radial symmetry or bilateral symmetry. In radial symmetry, organism have only one orientation, front and back (or top and bottom). Organism with bilateral symmetry have a top (dorsal side), bottom (venral side), head (anterior end), and (posterior end). c) Cephalization. In animals with bilateral symmetry, there is a progressively grater in crease in nerve tissue concentration at the anterior end (head) as organism increase in complexity. e) Gastrovascular cavity. Gatrovascular cavities, or guts, are areas where food is digested. Two openings designate a digestive tract, allowing specialized activities to occur as food travels from beginning to end. f) Coelom. During the embryonic development in more advanced animals, a cavity called a coelom develops from tissue derived from the mesoderm germ layer. A coelomate animals lack a coelom, while pseudocoelomate animals have a cavity that is not completely lined by mesoderm-derived tissue. g) Segmentation. Many animals, such as insects and certain worms, have segmented body parts. h) Protostomes and deuterostomes. During the early development of the zygote, cell divisions, or cleavages, take place in an orderly fashion. Specific cleavage patterns emerge that result in the development of particular embryonic features. Three major differences between these two groups are evident as described below and outlined. a. Early cleavages either are at a slight angle (spiral cleavage) or are parallel (radical cleavage) to the vertical axis of the embryo. b. When the embryo is configured as a sphere of cells, there is an information in the sphere that forms an internal cavity called the archenteron. c. The coelum can develop either from a spitting of the mesodermal tissues at each side of the archenteron or directly from outpouching in the wall of the archenteron. C) Major evolutionary trends are summarized: a) Porifera are the sponges. They feed by filtering water drawn through the sponge wall by flagellated cells called choanocytes. Water exists through an opening called the osculum. b) Cnidaria include hydrozoans, jellyfish, sea anemones, and corals. There are two body forms. One is the medusa, a floating, umbrellashaped body with dangling tentacles typical of jellyfish. The second is the polyp, asessile, cylinder-shaped body with rising tentacles typical of sea anemones. c) Platyhelminthes consist of three kinds of acoelomate flatworms. Free- living flatworms, such as planarians, are carnivores or scavengers that live in marine or freshwater. Flukes are internal animal parasites or external animal parasites that suck tissue fluids or blood. d) Nematoda are round worms. They have pseudocoelomate bodies with a complete digestive tract. Many nematodes are free-living soil dwellers that help decompose and recycle nutrients. e) Rotifera are rotifers. Although many are microscopic, they are multicellular, with specialized organs enclosed in a pseudocoelom, and have a complete digestive tract. f) Mollusca include snails, bivalves, octopuses, and squids. Most mollusks have shells. g) Annelida are segments worms. They include the leeches, earthworms, and polychaete worms. Leeches are either predators of small animals or blood – sucking parasites. h) Arthropoda include spiders, insects, crustaceans, and various related organisms. They have jointed appendages, a well-developed nervous system, specialization of body segments, and an exoskeleton made of chitin. i) Echinodermata include sea stars, sea urchins, and sand dollars. They are coelomate deuterostomes and usually have a complete digestive tract. j) Chordata consist of animals that exhibit the following four main futures. a) A notochord provides a dorsal, flexible rod that functions as a support. In most chordates, the notochord is replaced by done during development. b)A dorsal hollow nerve cord forms the basis of the nervous system. In some chordates, the nerve cord becomes the brain and spinal cord. c) Pharyngeal gill slits provide channels across the pharynx 9 a muscular structure at the beginning of the digestive tract) to the outside of the body. d) A muscular tail extends beyond the digestive tract. In many chordates, such as humans, the tail is lost during embryonic development.