Diversity in living organisms
Pine tree live for thousands of year.
Greek thinker Aristotle classified animals based on land, water and on air.
Habitat is the only point they share in common.
Characteristic is a particular form or a particular function.
A eukaryotic cell has membrane-bound organelles, including nucleus.
Cells that group together to form a single organism’s use the principle of division of labour.
They are organisms that produce food on their own while other taking from external
All living things are identified and categorized on the basis of their body design in form and
Evolution – most life forms that we see today have arisen by an accumulation of changes in
body design that allows the organisms possessing them to survive better.
Charles Darwin first described evolution in 1859 in his book “The orgin of species”.
Those in the first group are referred to as primitive or lower organisms.
Those in the second group are referred to as advanced or higher organisms.
Biodiversity means the diversity of life forms.
Biologist- Ernst Haeckel, Robert Whitttaker and Carl Woese have tried to classify all living
organisms to broad categories, called kingdoms.
The classification of Whitakker has five kingdoms
Woese modified by dividing Monera into Archabacteria (or Archaea) and Eubacteria (or
Phylum (animals)/division (plants)
Basic unit of classification is species.
A species includes all organisms that are similar enough to breed and perpetuate.
1. These organisms do not have a defined nucleus or organelles.
2. Some of them have cell walls, some do not.
3. They show diversity based on characteristic.
4. The mode of nutrition is either by synthesizing their own food (autotrophic) or
getting food from environment (heterotrophic).
5. E.g. bacteria, blue green algae or cyanobacteria, and mycoplasma.
This group includes many unicellular eukaryotic organisms.
Some of these organisms use appendages, such as hair like cilia or whip-like flagella.
The mode of nutrition can be autotrophic or heterotrophic.
E.g. unicellular algae, diatoms, and protozoan.
These are heterotrophic eukaryotic organisms.
These use decaying food material as food, therefore they are called saprophytes.
Many of them have capacity to become multicellular organisms.
They have cell walls made up of complex sugar called chitin.
E.g. Yeast and mushrooms.
Sometimes they live in permanent dependent relationship with blue green algae (or
cyanobacteria). Such relationships are called symbiotic.
We see lichens as the slow- growing large colored patches on the bark of trees.
Toad – mushroom poisonous
They are multicellular eukaryotic with cell walls.
They are autotrophs and us chlorophyll for photosynthesis.
All plants are included in this.
1. All organisms which are multicellular eukaryotes without cell walls.
2. They are heterotrophs.
Classification among plants depends on whether the plant has well differentiated, distinct
Next classification among plants is the differentiated plant body has special tissues for the
transport of water and other substances.
They look at the ability to beer seeds and seeds are enclosed within fruits.
1. Plants don’t have well- differentiated body design.
2. The plants in this group are commonly called alga.
3. These plants are predominantly aquatic.
4. E.g. spirogyra, ulothrix, cladophora and chara.
1. These are called the amphibians of the plant kingdoms.
2. The plant body is commonly differentiated to form stem and la-like structure.
3. They do not have specialized tissue for the conduction.
4. E.g. moss (funaria) and marchantia, riccia.
1. Plant body is differentiated into roots, stems and leaves.
2. They has specialized tissue for the conduction.
3. E.g. marsilea, ferns and horse tail.
4. The thallophytes, bryophytes and Pteridophyta have naked embryo that are called
5. The reproductive organs of plants in all three groups are very inconspicuous and they
are therefore called “crytogamae” or “those with hidden reproductive organs.”
6. Plants with well differentiated reproductive tissues that ultimately make seeds are
7. Classification based on whether the seeds are naked or enclosed in fruit. These give
two groups: gymnosperms and angiosperms.
1. These word is derived from Greek word gymno – naked
sperma – seed
2. The plants of these groups’ beer naked seeds are usually perennial, evergreen, and
3. E.g. pines, cycas and deodar.
1. Angiosperm is derived from two Greek word angio means covered and sperma
2. The seed is developed inside and modified to become a fruit. These are also called
3. Plant embryos in seeds have structure called cotyledons.
4. Cotyledons are called “seed leaves” because in many instance they emerge and
become green when the seed germinate.
5. The angiosperms are divided into two based on number of cotyledons.
6. Plants with single cotyledons are called monocotyledons or monocots.
7. Plants with two cotyledons are called dicots.
1. Most animals are mobile (moving).
2. They are classified into
(ii) Coelenterate (cnidaria)
(1) The word Porifera means organisms with holes don’t move.
(2) They are non/motile (don’t move) animals attached to some solid support.
(3) They have holes in their body. These lead to canal system that helps in circulating
water throughout the body to bring in food and oxygen.
(4) These animals are covered with hard cover called skeleton.
(5) They have minimum tissues.
(6) They are often called sponge. They are mainly found in marine habitats.
(7) E.g. sycon, euplectelea, spongilla
1) They are animals living in water.
2) They show body design differentiation.
3) There is a cavity in the body.
4) The body is made up of two layers of cells.
i. On the outside of the body
ii. Inner lining of the body.
5) Some of lives in colonies (coral), while others have a solitary like-span (hydra).
6) E.g. jellyfish, seaanemones, hydra, and coral.
1. The body is bilaterally symmetrical.
2. Three layers of celled animals are called triploblastic. This allows outside and inside
body lining as well as some organs to be made.
3. The body is flattered dorsiventrally, meaning from top to bottom, these animals are
4. They are either free living or parasitic animal.
5. E.g. Free living – planarians
Parasitic – liver flukes
1. They are bilaterally symmetrical and triploblastic.
2. The body is cylindrical rather than flattened.
3. There are tissues although a sort of body cavity or a pseudocoelem is present.
4. They are parasitic worms causing disease such as the worms causing elephantiasis
5. E.g. Ascaris, Wuchereria.
1. Annelida animals are bilaterally symmetrical and triploblastic.
2. In addition, they have true body cavity. This allows true organs to be packaged in
the body structure.
3. In this group animals body in which the segments lined up on after the other from
head to tail.
4. These animals are found in fresh water, marine water as well as land.
5. E.g. Leeches, Earthworms and Nereis.
1. This is probably largest group of animals.
2. They are bilaterally symmetrical and segmented.
3. There is open circulating system so the blood doesn’t flow in well defined blood
4. They have joined leg.
5. The word arthropod means “joined legs”
6. E.g. Pralaemon (Prawn), palamnaeus (scorpion), aranea (spider), pariplanta
(cockroach), Musca (housefly), scolopendra (centipede).
1. They are bilaterally symmetrical.
2. They coelomic cavity is reduced.
3. They have little segmentation.
4. They have open circulating system and kidney – organs for excretion.
5. They will have foot to move around.
6. E.g. snails, mussels, chitun, octopus, pila and unio.
1. In Greek, Echinus means hedgehog and derma means skin.
2. They are spiny skinned organisms.
3. They are free – living marine water.
4. They are triploblastic and have a coelomic cavity.
5. They have calcium carbonate structure instead of skeleton.
6. E.g. antedon (feather star), Echinus (sea urchin), Asterias (star fish).
1. These animals are bilaterally symmetrical, triploblastic and have a coelom.
2. They show new feature of body design, namely a notochord.
3. The notochord is a long rod – like support – structure that runs along the back of
animals separating the nervous tissue from the gut.
4. It provides a place for muscle to attach to ease of movement.
5. Protochordata animals are marine animals.
6. E.g. Balanoglossus, Herdmania and Amphioxus.
1. These animals have a true vertebral column and internal skeleton. This allows
completely different distribution of muscle attachments points to be used for
2. Vertebrates are bilaterally, symmetrical, triploblastic, coelomic and segmented.
3. Chordates posses the following features
(i) Have a notochord
(ii) Have a dorsal nerve cord
(iii) Are triploblastic
(iv) Have paired gill pouches.
(v) Are coelomate
4. Vertebrates are classified into five classes
They are fish.
They are aquatic animals.
Their skin is covered with scales/ plates.
They obtain oxygen from water using gills.
The body is streamlined and a muscular tail is used for movement.
They are cold – blooded
Their heart has two – chambered only.
They lay eggs.
E.g. Synchiropus splendidus (Mandarin fish), Caulophyryne jordani
(Angle fish), Pterois volitans (lion fish), Electric ray ( Torpedo) , String ray,
Scoliodon ( dog fish), Labeo rohita (Rohu), Male Hippocampus (sea horse),
Exocoetus (flying fish), Anabas ( Climbing perch).
They lack scale.
They have mucus glands in the skin.
They have three – chambered heart.
Respiration is through lungs or gills.
They lay eggs.
They are found both in land and on water.
E.g. Frogs, Salamander, Toads.
1. These animals are cold – blooded.
2. They are scales.
3. They are breathing through lungs.
4. They have three chambered heart.
5. They lay eggs with tough covering and do not need to lay eggs in water or somewhere
6. E.g. snakes, turtles, lizards and crocodiles, Chameleon, Flying lizard, House wall lizard.
1. They are warm blooded animals.
2. They have 4- chambered heart.
3. They lay eggs.
4. They have outside covering of feathers and two forelimbs are modified for flight.
5. They breathe through lungs.
6. All birds fall in this category.
1. Mammals are warm- blooded animals.
2. They have 4 – chambered heart.
3. They have mammary gland to nourish their young by the production of milk.
4. Their skin has hairs as well as sweat and oil glands.
5. Some mammals give birth to young ones.
6. Platypus and the echidna fall in the category of laying eggs.
1. The scientific name for an organisms is unique and can be identified it anywhere in
2. The system of scientific naming is called nomenclature.
3. Nomenclature was introduced by Carolus Linnaeus.
4. Certain convection are followed while writing the scientific name :
4.1. The name of genus begins with capital letter.
4.2. The name of species begins with lowercase letters.
4.3. When printed, the scientific name is in Italics.
4.4. When written with hand the genus name and species name have to be