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.
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.
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
The Hierarchy of Classification • Whittaker Proposed Five Kingdom Classification: 1. Monera2.Protista3. Fungi 4.Plantae5.Animalia • The Criteria of Five Kingdom Classification: 1. Cell Structure 2. No. of Cells 3. Mode & Source of Nutrition 4. Body Organisation Kingdom→Phylum / Division → Class → Order → Family → Genus → Species
Species • Basic unit of classification. • Group of closely resembling organisms that can interbreed in nature. • A number of closely related species form a genus
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 Heterotrophic e.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 • 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) • Name the five kingdoms in Whittaker’s classification. State the criteria used for this classification. • Photosynthetic Anabaena is included in kingdom Monera. Why? • Name the costituents of a lichen. • 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 aquatic e.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.
PHYLUM Porifera Coelenterata Platyhelminthes Nematoda Annelida Arthropoda Mollusca Echinodermata INVERTEBRATES
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
spider scorpion More Arthropods
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 • How can you differentiate earthworm from round worm? • Give three differences between Porifera and Cuidaria. • Which of the following is odd one out? (Planaria, Liverfluke, Tapeworm, Earthworm) • Give the phylum of the following animals and state two salient features of their Phyla. a. Prawn b. Octopus c. Sea Urchin • 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 CarolusLinnaous. • 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, MangifersIndica (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
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: • Apical, • Lateral, and • Intercalary.
Types of Meristem • Apical Meristem: Present at growing tips of stem and root and responsible for elongation of stem and root. • Lateral Meristem: Located parallel to the long axis. Responsible for increase in girth of stem and root. • 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.