DIVERSITY IN

LIVING ORGANISMS

Some Scientists who gave the classification of organisms

Aristotle

Charles Darwin

Linnaeus

Robert H. Whittaker

E. H. Haeckel

Carl Woese

Theophrastus

Walter G. Rosen

ClassificationScience of arranging organisms in series of groups and subgroups on the basis of their similarities and dissimilarities . Aristotle classified organisms on the basis of their habitat means the place where they live ,in water , in air and on land.

Basis Characteristics of Classification

Nature of cell : Prokaryotic or Eukaryotic Cellularity : Unicellular or Multicellular Level of organization : Cellular , Tissue , Organ and Organ systemMode of nutrition : Autotrophic or Heterotrophic

Classification and Evolution Time is the key factor which helps in development off complex organisms from the simple ones . Charles Darwin firstly gave the idea of evolution in 1859 in his famous book “THE ORIGIN SPECIES” . Those organisms which have ancient body design and not changed much are called primitive organisms . Those who acquired certain special characters during the time period are known as advanced on higher organisms .

Biodiversity Biodiversity is the term used for various forms of life found in a given area . These life forms depends on each other and on the environment and result in a stable community. Human also is the part of this biodiversity . It is estimated that there is about 10,000,000 species on this planet , we know only about 20,00,000 species.

Hierarchy of classification

Ernst Haeckel , Robert Whittaker , Carl Woese have tried to classify all living organism into broad categories. R.Whittaker proposed five kingdom system which is widely used . This kingdom includes Monera , Protista , Fungi , Plantae, and Animalia . Carl Woese divided Monera into Archaebacteria and Eubacteria .

Further classification Living organisms have been broadly classified into five main kingdoms. They are :-

i) Monera ii) Protista iii) Fungi iv) Plante v) AnimaliaEach kingdom has been further classified into smaller sub - groups at various levels as :- Kingdom Phylum (for plants) / Division (for animals) Class Order Family Genus Species By arranging organisms on the basis of hierarchy and characteristics into smaller and smaller groups we arrive at the basic unit of classification called species.

Further classification Further classification is done by naming the sub groups at various levels as given : Kingdom Phylum / Division Class Order Family Genus Species

• Kingdom Monera • Kingdom Protista •Kingdom Fungi •Kingdom Plantae• Kingdom Animalia

The five kingdom classification

Kingdom Monera• Unicellular and Prokaryotic organisms • Nucleus and cell organelles are absent • May or may not have cell wall• Autotrophic or heterotrophic• Able to nitrogen fixation •Reproduce by asexual methods• Bacteria , cyanobacteria and mycoplasma

Kingdom Protista • Unicellular and Eukaryotic organisms • A well defined nucleus and cell organelles are present • They may be autotrophic or heterotrophic• Some of these organisms like cilia and flagella for movement• They reproduce by both sexual and asexual methods• Diatoms , protozoans are few example

Kingdom Fungi• Heterotrophic eukaryotic organisms • Saprophytes• Cell wall made of chitin• Some of them live in close relationship with certain algae and plants forming Lichens and Mycorrhizae• Some of them have the ability of being multicellular • Yeast , mushroom and rhizopus

Kingdom Plantae• They are multicellular eukaryotic organisms .• This kingdom includes all the plant species .• They are autotrophic and prepare their own food .• they are further classified into five major divisions.

Classification of Plant

Cryptogamae•A cryptogam (scientific name Cryptogamae) is a plant that reproduces by spores, without flowers or seeds. "Cryptogamae” means hidden reproduction, referring to the fact that no seed is produced, thus cryptogams represent the non-seed bearing plants. The best known groups of cryptogams are -algae, lichens, mosses and ferns

Flowerless or seedless plants . Lower and more primitive plants. Hidden Reproductive Organs. Reproduction By spores. 3 main groups i.e. Thallophyte,

Bryophyte and Pteridophyte Now we would learn about divisions.

Charateristics of Cryptogamae

Thallophyta•Body of the organisms is not differentiated into organs.•Mainly aquatic found in marine and fresh water.•Tissue for conduction of material and for mechanical strength is absent.•They are covered by mucilage.•Reproduce by vegetative, asexual and sexual reproduction.•Algae are example of this division.

Bryophyta•Plant body is differentiated into leaf, root and stem like structures.•Special conducting tissues are not present.•These are known as amphibians of plant kingdoms.•Reproduce by vegetative, asexual and sexual reproduction.•Funaria, Anthoceros and Marchantia are few examples.

Pteridophyta•Plant body is differentiated into leaf, stem and roots.•They also have conductive tissues. •All the above discussed plant types doesn’t bear seeds instead they bear spores. They are also known as cryptograms.•They require water for the purpose of reproduction.•Fern, Adiantum and Selaginella are few examples

PhanaerogamaePhanerogamae are seed bearing plants with evident reproductive organs called flowers.On the basis of naked or protected ovules and absence or presence of fruits, the subkingdom Phanerogamae is divided in to two sub-kingdoms.

Gymnosperms Angiosperms.

Characteristics of Phanaerogamae The plant body is saprophytic

( diploid ) and differentiated into true stem ,leaves and roots.

Vascular tissues are present which forms a vascular system

Sex organs are well developed and multicellular.

After fertilization, an embryo develops from fertilized egg.

•These plants bear naked seeds mean seeds are not enclosed in fruits.•These are perennial, evergreen trees having woody trunk.•They bear cones in which seeds are placed.•Sequoia sempervirens is the largest tree found on earth (125 Meters) is an example. Other examples are Pinus, Cycas.

Gymnosperms

•Bear seeds covered by special organs known as fruits.•They bear flowers as their reproductive organs.•Embryo in seed has special structure called cotyledons which act as seed leaves at the time of germination.•They are divided into two groups: Monocots and Dicots.• Wheat, Rice, Rose and Tomato are examples of this division.

Angiosperms

Kingdom Animalia•Main characteristics of this kingdom are as follows:•These are eukaryotic organisms of heterotrophic nature.•These are multi-cellular organisms.•Their cells do not bear cell walls and chloroplasts.•They are further subdivided into following categories:

Classification of Animal

•These animals bear small holes on their body surface.•They are aquatic and sedentary means non motile.•They have cellular level of body design.•They bear hard external skeleton and have a canal system for the distribution of food and gases.•Spongilla and Sycon are the examples.

Porifera

•They are aquatic animals and have tissue level of body design.•They have a body cavity called coelom so named as coelentrata.•They may be solitary or colonial.•They have special stinging cells called cnidoblasts so also known as Cnidaria.•Hydra, Obelia and Physalia are few examples.

Coelenterata

•Show bilateral symmetry and are triploblastic mean have three germ layers.•They are dorsoventrally flattened so also called flatworms.•They are either free living or parasitic.•They have tissue level of body design.•They do not have any body cavity•Planarian and Liver flukes are examples

Platyhelminthes

•These animals show bilateral symmetry and are triploblastic mean have three germ layers.•They are cylindrical in shape.•They have a pseudocoelom.•They have tissue level of body design.•They are mainly parasitic in nutrition.•Ascaris and Wuchuraria are examples.

NEMATODA

•Show bilateral symmetry and are triploblastic.•They are cylindrical in shape and have a true body cavity.•Organ system level of body design is found.•Body is divided into small segments called annuli so phylum is also known as Annelida.•They found in both land and water.•Earthworm and Leech are examples.

Annelida

•These animals show bilateral symmetry and are triploblastic mean have three germ layers.•They have a true body cavity which is blood filled.•Organ system level of body design is found.•Open circulatory system is found in these animals.•Largest group of animals.•They have jointed legs.•Cockroach, Housefly, Butterfly are examples

ARTHROPODA

•Body cavity is highly reduced•These animals show bilateral symmetry and are triploblastic mean have three germ layers.•They also have open circulatory system.•They have kidney like structure for excretion.•A highly muscular foot is used for movement.•Pila and Chiton are examples

Mollusca

•They are spiny skin organisms.•They are free living animals found only in marine water.•They are triploblastic and have true body cavity.•They have a tube system for the purpose of movement.•They show high power of regeneration.•Starfish and Sea urchin are examples

Echinodermata

•These animals show bilateral symmetry and are triploblastic mean have three germ layers.•They are cylindrical in shape and have a true body cavity.•They also have a notochord at any stage of life which provide surface for the attachment of muscles and to provide support.•Amphioxus, Balanoglossus.

Protochordata

•They have notochord at any stage of life.•They have a dorsal nerve cord.•They are triploblastic.•They have paired gill pouches.•They have true body cavity.•They includes classes: Pisces, Amphibia, Reptilia, Aves and Mammalia

Vertebrata

•They are aquatic found in fresh and marine water.•Skin is covered by scales or plates and have gills for respiration.•Body is streamlined and has a tail.•They have two chambered heart and are cold blooded.•Skeleton is made up of either cartilage or of bone.•Scoliodon and Labeo rohita.

Pisces

•They are animals with uncovered skin which help in gas exchange.•They have three chambers in heart and are cold blooded.•They are found in both water and on land.•They lay eggs without any hard shell.•Frog and Salamanders.

Amphibla

•They are terrestrial as well as aquatic.•Skin is covered by scales.•They are cold blooded animals mostly having three chambers in heart except crocodile.•Their eggs are covered by a hard shell.•They breathe through lungs.•Snakes and tortoise.

Reptilia

•They have four chambers in heart and are warm blooded.•They breathe through lungs.•They lay eggs covered by hard shells.•Their body is covered by feathers and are very good fliers.•They do not have teeth and bear beak and claws.•All the birds are examples.

Aves

•They have four chambers in heart and are warm blooded.•They breathe through lungs.•They have mammary glands for the production of milk.•They have hairs and nails as well as sweat and oil glands.•They give birth to young ones except Platypus and Echidna.•All the milk producing animals including humans

Mammalia

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