Diversity in Living Organism

Organisms differ in size, lifespan, colour, feeding habit.

Microscopic bacteria and 30 metre long blue whale, 100 metre tall redwood trees.

Pine trees live for thousands of years while mosquitoes die within a few days.

Transparent worms and brightly coloured birds or flowers.

….Diversity in Living Organism

Basis of Classification

Aristotle classified animals according to whether they lived on land, in water or in the air.

Corals, whales, octopuses, starfish live in sea but they are entirely different from each other.

Habitat is the only point they share in common.

Characteristic is a particular form or a particular function.

….Basis of Classification

Characteristics Used for Hierarchical Classification

Nature of the Cell - Prokaryotic or Eukaryotic

Unicellular or multi cellular Autotrophic (Photosynthetic) or

Heterotrophic Level of Organization

Cellular Tissue level Organ Organ system

Prokaryotic or Eukaryotic

The Hierarchy of Classification

Whittaker Proposed Five Kingdom Classification:1. Monera 2. Protista 3. Fungi4. Plantae 5. Animalia

The Criteria of Five Kingdom Classification:1. Cell Structure 2. No. of Cells3. Mode & Source of Nutrition 4. Body Organisation

Kingdom→Phylum / Division → Class → Order → Family → Genus → Species

Robert Whittaker & The Five Kingdom Classification

Species

Basic unit of classification. Group of closely resembling

organisms that can interbreed in nature.

A number of closely related species form a genus

Species

Monera

Prokaryotic cells Unicellular Most of them have cell wall (Bacteria) Some do not possess cell wall

(Mycoplasma) Autotrophic (Cyanobacteria) or

Heterotrophic (Lactobacillus)e.g, Bacteria, Blue green Algae

(Cyanobacteria), and mycoplasma.

Protista

Unicellular and Eukaryotic Presence of Cilia, Flagella or

Pseudopodia for locomotion Autotrophic (Diatoms) or

Heterotrophice.g, Diatoms, Protozoans, Euglenoids

Fungi

Multi cellular, Eukaryotic heterotrophs. Many are saprophytes – use decaying

material as food. Some are parasitic, symbiotic. Cell wall made of a complex sugar called

chitin. Lichens are symbiotic association

between a fungus and an alga (Blue green algae).

e.g, Yeast, Mushroom, Penicillium, Rhizopus, Aspergillus.

Plantae

Multicellular, eukaryotic organisms. Photosynthetic (Photo auto trophs). Presence of cell wall and chlorophyll.

Animalia

Multi cellular eukaryotes without cell wall.

Heterotrophs (Holozoic nutrition)

Questions

1. The various levels in the hierarchy of classification is given below. Arrange them by starting from the basic unit in classification. (Kingdom, genus, family, species, class, order)

2. Name the five kingdoms in Whittaker’s classification. State the criteria used for this classification.

3. Photosynthetic Anabaena is included in kingdom Monera. Why?

4. Name the costituents of a lichen.5. Which of the following possess cell wall.

(Amoeba, Euglena, Penicillium, Paramecium)

Classification of plants

Nature of plant body – undifferentiated thallus or well differentiated.

Presence of conducting tissue. Presence of seeds and nature of seed

(enclosed seed or naked seed)

thallophyta

Do not have well differentiated body (thallus).

Predominantly aquatice.g, Alage Cladophora, Spirogyra, Chara, Urva,

Ulothrix

Bryophyta

Amphibians of the plant kingdom. Plant body is differentiated into stem

like, leaf like and root like (rhizoids) parts.(undifferentiated in some)

Lack of vascular tissue for conduction.

e.g, Funaria (Moss), Marchantia, Riccia

Pteridophyta

Plant body is differentiated into root, stem and leaf.

Presence of vascular tissues for conduction.

Produce spores in sporangium.e.g, Marsilea, Horse-tails, Ferns. Reproductive organs are inconspicuous

in thallophyta, bryophyta and pteridophyta and so they are called cryptogamae (those with hidden reproductive organs)

Phanerogams

Seed producing plants. Seed consists of embryo and stored

food. Divided into two – Gymnosperms (naked

seed bearing plants and angiosperms enclosed seed bearing plants.

Gymno sperms are naked seed bearing plants.

Plants of this group are perennial, evergreen, and woody.

e.g, Cycas, Pinus

Angiosperms (Flowering Plants)

Enclosed seed bearing plants- seeds areinside the fruit.

Flowering plants – Flowers are the reproductive organs.

Embryos in the seed have cotyledons (seed leaves)

Based on the number of cotyledons for the embryo, angiosperms are divided into two classes – dicotyledons (two cotyledons) and monocotyledons (one cotyledon)

e.g,…. Dicots – Ipomoea, Mango, Bean, Tomato Monocots – Paddy, Coconut, Banana, Orchids

Questions

a. How are bryophyta different from pteridophyta ?

b. Mention the criteria of classifying angiosperms into two classes.

c. Give the difference between gymnosperms and angiosperms.

d. Mention three groups of eryptogerms and mention the salient features of each group.

INVERTEBRATES

PHYLUM• Porifera• Coelenterata• Platyhelminthes• Nematoda• Annelida• Arthropoda• Mollusca• Echinodermata

PORIFERA

Pores on the body Non-motile and

attached to solid support.

Have hard outside layer Pores lead to canal for

circulating water. Simple body design –

lack of tissues. Body cavity-

spongocoel Osculum at the upper

end Examples : Sycon ,

spongilla

Coelenterata (Cnidaria)

Aquatic , Mostly marine. Tissue level of

organisation. Radial symmetry. Diploblastic – body has

two layers of cells, outer epidermis and inner gastrodermis.

Gastrovascular cavity Stinging cells –

nematocysts. Example: Hydra, Sea

anemone, Jelly fish.

Platyhelminthes (flat worms)

Dorsiventrally flat body. Acoelomate(no true

internal body cavity ) Triploblastic Bilaterally symmetrical Complex body design Mostly parasites, some are

free living Example: Tope worm,

Liverfluke, Planaria

NEMATODA ( ASchelminthes)

Bilaterally symmetric, triploblastic

Cylindrical body Pseudocoelom Many are parasites Example: Ascaris,

Wuchereria, Pin worm, Hook worm.

Annelida

Segmented body Bilaterally symmetrical

and triploblastic. True body cavity

(coelomate) Extensive organ

differentiation Closed

circulation,Nephridia as excretory organ, Setae or parapodia help in locomotion.

Example: Earthworm, Leech, Nereis

Arthropoda

Jointed legs Segmented body Bilaterally symmetrical,

triploblastic Chitinous exoskeleton Coelomic cavity is blood

filled(haemocoel) Open circulation Example: Cockroach,

Prawn, Spider, Scorpion, Centipede, Housefly, Honeybee……..

LARGEST PHYLUM

More Arthropods

spider scorpion

Mollusca

Soft bodied animals Protective shell Open circulation Muscular foot for

locomotion Bilaterally symmetric with

little segmentation Kidney like organ for

excretion Respiration by gills Example: Pila, Unio,

Octopus, Chiton, Squid.

Echinodermata

Spiny skinned animals Free living marine animals Radially symmetrical Triploblastic and

coelomates Have water vascular

system for respiration and locomotion, tube feet help in locomotion

Have hard calcium carbonate crystals as skeleton

Example: Star fish, Sea urchin, Feather star, Sea cucumber.

Chordata

Presence of dorsal notochord. Presence of dorsal nerve cord. Presence of paired gill pouches. Presence of post anal tail. Triploblastic and coelomata. Divided into three subphyla - urochordata,

cephalochordata, and vertebrata. Urochordata and cephalochordata are

often called protochordata. All protochordata are marine.e.g, Balanoglossus, Amphioxus

Vertebrata

Notochord is replaced by vertebral column.

Ventral muscular heart with 2,3 or 4 chambered.

Kidneys for excretion and osmo regulation.

Paired appendages – fins or limbs. Grouped into five classes – Pisces,

Amphibia, Reptilia, Aves, Mammalia.

Pisces (Fishes)

Aquatic. Skin is covered with scales or plates. Obtain dissolved oxygen by using gills. Streamlined body and muscular tail for

movement. Cold blooded. Two chambered heart. Lay eggs. Cartilaginous fish – Skeleton made of cartilage e.g, Shark, electric Ray Bony fish – Skeleton made of bone e.g, Tuna, Rohu, Sardine etc.

Amphibia

Requires both land and water for completing life cycle.

Lack of scales, have mucus glands in the skin.

Three chambered heart. Respiration through lungs/gills. Lay eggs in water. External fertilisation.e.g, Frog, Toad, Salamander, Tree frog.

Reptilia

Cold blooded, have scales and breathe through lungs.

Most of them have three chambered heart, but crocodiles have four chambered.

Lay eggs with tough coverings. Internal fertilisation.e.g, Snakes, Wall lizard, Turtle,

Tortoise, Draco

Aves (Birds)

Warm blooded. Four chambered heart. Lay eggs with thick shell. Body is covered by feathers. Forelimbs are modified into wings. Breathe through lungs.e.g, Crow, Pegeon, Sparrow, Ostrich.

Mammalia

Have mammary glands. Give birth to young ones. Warm blooded with four chambered heart. Skin has hairs, sweat and sebaceous

glands. Have pinna. Egg laying mammals – Platypus and

Echidna. Kangaroo give birth to poorly developed

young ones.e.g, Human, Rat, Elephant, Cat, Bat, Whale.

Questions

1. How can you differentiate earthworm from round worm?

2. Give three differences between Porifera and Cuidaria.

3. Which of the following is odd one out? (Planaria, Liverfluke, Tapeworm, Earthworm)

4. Give the phylum of the following animals and state two salient features of their Phyla. a. Prawn b. Octopus c. Sea Urchin

5. Mention the differences between amphibians and reptiles.

Nomenclature

Find out the name of Potato/Onion in different languages.

The system of naming organisms by giving generic name and species name.

Introduced by Carolus Linnaous. Name of the genus begins with a capital

letter, Species name begins with small letter. When printed name is given in Italics. When hand written, underline separately for

genus and species. Oryza Sativa – Paddy, Mangifers Indica

(Mango), Panthera Tigris.

Tissues

In unicellular organisms, a single cell perform all basic functions.

But in multicellular organisms, the tissues/organs/organ system perform various functions.

Muscular tissue – contraction causes movement. Nerve cells – carry messages. Blood – transport food, Oxygen, hormone. Vascular tissues in plants – conduct water and

food. Division of labour in multicellular organisms. A group of cells that are similar in structure and/or

work together to achieve a particular function forms a tissue.

Are Plants & Animals made of same types of tissues ?

Plants are stationary. Most of the tissues are supportive and dead.

Animals can move around – consume more energy . Most tissues are living.

Growth in plants is limited to certain region – meristems.

Growth in animal is more uniform – no demarcation of dividing and non dividing regions in animals.

Plants Tissues

Meristematic tissues. Activity – in Page No. 69

Chapter: Tissues

Plant Tissue - Classification

Plant Tissue

Meristem Permanent

• Apical• Intercalary

Simple Complex

• Lateral • Parenchyma

• Xylem

• Collenchyma

• Phloem

• Sclerenchyma

Meristematic Tissues

Group of cells which are in a state of continuous division.

Have dense cytoplasm, prominent nuclei, thin cell wall, lack vacuole.

Depending on the location in the plant body, meristems are divided into three:

1. Apical,2. Lateral, and3. Intercalary.

Types of Meristem

1. Apical Meristem: Present at growing tips of stem and root and responsible for elongation of stem and root.

2. Lateral Meristem: Located parallel to the long axis. Responsible for increase in girth of stem and root.

3. Intercalary Meristem: Present at the base of leaves or internodes.

Permanent Tissue

Group of cells which have lost the ability to divide.

The process of taking up a permanent shape, size and a function is called differentiation.

Cells of meristematic tissue differentiate to form different types of permanent tissue.

Simple: Parenchyma, Collenchyma, Sclerenchyma.

Complex: Xylem and Phloem.

Simple Permanent Tissue

Parenchyma: Thin cellwall, living cell, usually

loosely packed, storage of food is the major function.

Chlorenchyma: Chlorophyll containing parenchyma. Function is photosynthesis.Aerenchyma: Parenchyma with air cavities to give

buoyancy to help them float.

Collenchyma

Corners of the cell wall is thickened. Have very little inter cellular space. Provide flexibility and mechanical

support to growing young parts.