Download Diversity in Living Organisms

Diversity in Living Organisms
There is a bewildering variety of organisms present on the earth.
Smallest organism – PPLO( Pleuro Pneumonia Like Organisms)
few micrometers in diameter.
Largest Animal- Blue Whale (30 mts)
Largest Plant- Red wood trees of California(100 mts)
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Why do we need to classify?
Being very large in number, individual life forms cannot be
studied, hence they are divided into groups and subgroups on
the basis of their similarities and differences.(Classification)
We cannot identify organisms/ fossils without proper system
of classification. We study about evolution.
Economic importance of groups of organisms can be
established.
Basis of Classification
Aristotle classified animals according to whether they lived on land,
in water or in the air. This was discarded later as it was misleading.
Fundamental differences are used to group organisms into
Kingdoms For Ex- 1. Presence/absence of a well organised nucleus
. Prokaryote- Monera. Eukaryote.
2. Unicellular/ Multicellular body design. Unicellular- Protista.
3. Mode of Nutrition- Autotrophic/ Heterotrophic. This could
dictate the body design of ornanisms which need to look for food
need to have locomotory organs (animals), while those who can
make their food don’t(plants).
4. Body development and organisation into parts, Presence of
specialised parts determine the grouping of organisms.
Classification and Evolution
Characteristics that came into existence earlier are likely to be
more basic than characteristics that have come into existence
later.
Charles Darwin first described the idea of evolution in 1859 in
his book, The Origin of Species. (Most life forms that we see today
have arisen by an accumulation of changes in body design that
allow the organism possessing them to survive better.)
Older organisms(primitive) are simpler, while younger
organisms(advanced) are more complex.
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Megadiversity
The warm and humid tropical regions of the earth, between
the tropic of Cancer and the tropic of Capricorn, are rich in
diversity of plant and animal life. This is called the region of
megadiversity.
More than half of diversity is concentrated in a few countries
– Brazil, Colombia, Ecuador, Peru, Mexico, Zaire,
Madagascar, Australia, China, India, Indonesia and Malaysia.
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The Hierarchy of Classification- Groups
Ernst Haeckel tried to classify all living organisms into broad categories,
called kingdoms.
Whittaker proposed five kingdom classification: Monera, Protista, Fungi,
Plantae and Animalia based on cell structure, mode and source of nutrition
and body organisation.
Woese modified by dividing the Monera into Archaebacteria (or Archaea)
and Eubacteria (or Bacteria) is also in use.
Species includes all organisms that are similar enough to breed and
perpetuate.
Kingdom
Phylum (for animals) / Division (for plants)
Class
Order
Family
Genus
Species
Kingdom MONERA
Prokaryotic.
Unicellular
Cell wall 1.present-Autotrophic 2. absent- Hetrotrophic
Mode of nutrition 1. Autotrophic – Cyanobacteria, Anabaena
2. Hetrotrophic - Mycoplasma
Bacteria
Anabaena
Kingdom PROTISTA
Eukaryotic
Euglena
Unicellular
Locomotory Structures-(appendages) such as hair-like cilia or
whip-like flagella for moving around.
Mode of Nutrition 1. Autotrophic- Algae, Diatoms
2. Heterotrophic- Protozoans
Amoeba
Paramoecium
Kingdom FUNGI
Eukaryotic
Multicellular
Mode of Nutrition- Saprophytic, Parasitic, Symbiotic (Lichens)
Aspergillus
Penicillium
Agaricus
Kingdom PLANTAE
Eukaryotes with cell walls
Multicellular.
They are autotrophs and use chlorophyll for photosynthesis
Division THALLOPHYTA
Plants that do not have well-differentiated body design
Spirogyra
Bag like undifferentiated body.
Predominantly aquatic
Eg- Algae- Spirogyra, Ulothrix, Cladophora and Chara
Chara
Ulothrix
Cladophora
Ulva
Division BRYOPHYTA
They are the amphibians of the plant kingdom.
The plant body is commonly differentiated to form stem and
leaf-like structures.
There is no specialised tissue for the conduction of water and
other substances from one part of the plant body to another.
Examples are moss (Funaria) and Marchantia
Riccia
Division PTERIDOPHYTA
Plant body is differentiated into roots, stem and leaves.
It has specialised tissue for the conduction of water and other
substances from one part of the plant body to another.
Marsilea,
ferns
horse-tails
Another classification -
Plant
Cryptogamae
(Plants with naked embryosspores, whose reproductive
organs are inconspicuous)
bryophytes
thallophytes
pteridophytes
Phanerogams(
Plants with well
differentiated
reproductive tissues that
make seeds )
angiosperms.
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gymnosperms
Division GYMNOSPERMS
gymno– means naked and sperma– means seed.
The plants of this group bear naked seeds and are usually
perennial(lives more than two years), evergreen(never looses
all its leaves at the same time) and woody.
Pinus
Cycas
ANGIOSPERMS
angio means covered and sperma– means seed.
The seeds develop in an organ which is modified to become a fruit.
These are also called flowering plants.
Plant embryos in seeds have structures called cotyledons(seed leaves)
Cotyledons represent a bit of pre-designed plant in the seed.
Monocot
One
cotyledon
Eg- Grass
Angiosperms
Dicot
Two
cotyledons
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ANGIOSPERMS
Monocot-Paphiopedilum
Dicot-Ipomoea
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Kingdom Animalia
Eukaryotic,
Multicellular
Heterotrophic.
Their cells do not have cell-walls.
Most animals are mobile.
Further classification based on the extent and type of the
body design differentiation found.
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Phylum Porifera - sponges
Porifera means organism with holes
The holes lead to central canal which helps the body to
circulate food and oxygen .
Asymmetrical.
Cellular level organisation.
Exoskeleton of spicules made up of silica.
Habitat-Marine
Spongilla
Euplectelia
Sycon
Phylum Cnidaria
Body made up of two layers of tissue- ectoderm outer layer and
endoderm the inner layer.
It also has a false cavity.
Habitat- aquatic
They are eitherColonial (corals), or solitary Hydra).
Jellyfish and sea anemones are common examples
Sea anemone
Hydra
Phylum-PLATYHELMINTHES
The body is bilaterally symmetrical,(left and the right halves of the
body have the same design).
Triploblastic-(three layers of cells)
Tissue level differentiation
No true internal body cavity or coelom
The body is flattened dorsiventrally, which is why they are flatworms.
They are either free living-planarians or parasitic-liverflukes.
Planaria
Liverfluke
Flatworm
Phylum NEMATODA
Bilaterally symmetrical
Triploblastic
The body is cylindrical rather than flattened.
Pseudocavity present
Tissue level differentiation
They are parasitic-filarial worms (elephantasis), roundworm
or pinworms.
Wuchereria
Ascaris
Phyllum ANNELIDA
Bilaterally symmetrical
Triploblastic
True body cavity
Organ level differentiation
Segmented body
Habitat- fresh water,
marine and terristrial
Examples
Neres
Earthworm
Leech
Phyllum ARTHROPODA
(largest group of animals)
Bilaterally symmetrical
Segmented ( Head, thorax and abdomen)
Open circulatory system
Blood-filled coelomic cavity
They have jointed legs.
Hardened chitinous exoskeleton
Prawn
Cockroach
House Fly
Centipede
Scorpion
Phyllum MOLLUSCA
Bilateral symmetry.
The coelomic cavity is reduced.
Chiton
There is little segmentation.
They have an open circulatory
system
Kidney-like organs for excretion. Pila
There is a foot that is used for moving around.
Exoskeleton make of calcium carbonate present.
Octopus
Unio
Phyllum ECHINODERMATA
(Spiny Skined animals)
In Greek, echinos means hedgehog, and derma means skin.
Triploblastic
Have a coelomic cavity
These are exclusively free-living marine animals.
Water-driven tube system is used for moving around.
Subepidermal system made of calcareous plates.
Phyllum Chordata
bilateral symmetry
true coelom
triploblastic structure (endoderm, mesoderm and ectoderm)
tube-within-a-tube body plan
all organ systems are present
Subphyllum
PROTOCHORDATA
Bilaterally symmetrical,
Triploblastic
Have a coelom.
Marine animals
Balanoglossus
They have a notochord, at least at some stages of their life.
The notochord is a long rod-like support structure
(chord=string) that runs along the back of the animal
separating the nervous tissue from the gut. It provides a place
for muscles to attach for ease of movement.
Herdemania and Amphioxus
Subphyllum VERTEBRATA
true vertebral column
Internal skeleton, which has points for attachment of muscles
to bring about locomotion.
bilaterally symmetrical
Triploblastic
Class Pisces
Aquatic
Their skin is covered with scales/plates.
They obtain oxygen dissolved in water by using gills.
The body is streamlined, and a muscular tail is used for movement.
They are cold-blooded and their hearts have only two chambers
They lay eggs.
Two types1.Cartilagenous(skeletons made entirely of cartilage), eg. sharks,
2. Bony (skeleton made of both bone and cartilage) eg tuna or rohu
Cartilagenous fish
Bony Fish
Climbing Perch
Manadarin fish
Lion fish
Electric Ray
Rohu
Sting Ray
Sea Horse
Angler fish
Dog fish
Flying fish
Class Amphibia
Toad
They have mucus glands in the skin
Three-chambered heart.
Respiration is through either gills or lungs.
They lay eggs.
These animals are found both in water and on land.
Salamandar
Tree Frog
Common Frog
Class Reptilia
King Cobra
Cold-blooded,
Have scales
Breathe through lungs.
Most have a three-and half chambered heart,
Crocodiles have four heart chambers.
Lay eggs with tough coverings.
Turtle
Chamelion
Flying lizard
Wall Lizard
Ostrich
Class Aves
Warm-blooded animals
Have a four-chambered heart.
They lay eggs.
There is an outside covering of feathers,
Two forelimbs are modified for flight.
They breathe through lungs.
Pigeon
Sparrow
Male tufted duck
White Stork
Crow
Class Mammalia
Warm-blooded animals
Four-chambered hearts.
Mammary glands produce milk
to nourish their young.
Their skin has hairs as well as
sweat and oil glands.
Produce live young ones.(Except platypus and the echidna who
lay eggs, and kangaroos give birth to poorly developed young ones)
Binomial Nomenclature
Scientific naming or nomenclature was introduced by
Carolus Linnaeus in the eighteenth century.
The scientific name for an organism is unique and can be
used to identify it anywhere in the world.
Rules of writing the scientific name of organisms
1. The name of the genus begins with a capital letter.
2. The name of the species begins with a small letter.
3. When printed, the scientific name is given in italics.
4. When written by hand, the genus name and the species
name have to be underlined separately.
Some Scientific names
Lotus Peacock Tiger Lion Man-
Nelumbo nucifera
Pavo cristatus
Panthera tigris
Panthera leo
Homo sapiens