Plants & Animals

Five-kingdom classification (Whittaker, 1969):

1. Monera — unicellular prokaryotes (no nucleus): bacteria, blue-green algae.
2. Protista — unicellular eukaryotes: amoeba, paramecium, algae.
3. Fungi — multicellular, non-photosynthetic, cell wall of chitin: mushrooms, yeasts, moulds.
4. Plantae — multicellular, photosynthetic, cell wall of cellulose.
5. Animalia — multicellular, heterotrophic, no cell wall.

Plantae (further classified):

• Thallophyta: simple, no roots/stems/leaves. Algae, lichens.
• Bryophyta: mosses, liverworts. Need water for reproduction.
• Pteridophyta: ferns. Have vascular tissue but reproduce by spores.
• Gymnosperms: naked seeds. Pines, cedars, cycads.
• Angiosperms: flowering plants; seeds enclosed in fruit. Most numerous.
  • Monocots (one seed-leaf): rice, wheat, maize, banana, palm. Parallel-veined leaves.
  • Dicots (two seed-leaves): mango, pea, mustard, neem. Net-veined leaves.

Animalia (key phyla):

• Porifera: sponges. Pore-bearing; aquatic.
• Coelenterata / Cnidaria: jellyfish, corals, hydra. Stinging cells.
• Platyhelminthes: flatworms — tapeworm, planaria.
• Nematoda: roundworms — Ascaris, hookworm.
• Annelida: segmented worms — earthworm, leech.
• Arthropoda: jointed legs, exoskeleton — insects, spiders, crabs. Largest phylum.
• Mollusca: snails, octopus, oysters. Soft-bodied, often with shell.
• Echinodermata: starfish, sea urchin. Marine, spiny skin.
• Chordata: notochord. Subdivides into vertebrates (fish, amphibians, reptiles, birds, mammals).

Vertebrate classes:

• Pisces (fish): cold-blooded, gills, fins, scales. Lay eggs in water.
• Amphibia: frog, toad, salamander. Cold-blooded, breathe through skin + lungs. Tadpole stage in water.
• Reptilia: snake, lizard, turtle, crocodile. Cold-blooded, scaly skin. Lay eggs.
• Aves (birds): warm-blooded, feathered, lay eggs. Adapted for flight.
• Mammalia: warm-blooded, hair, mammary glands, viviparous (live birth) — except echidna, platypus (egg-laying mammals).

Plant adaptations:

• Cactus: spines (modified leaves), thick stems store water — desert adaptation.
• Lotus: floating leaves, hollow stems — aquatic.
• Mangroves: salt-tolerant roots (pneumatophores) — coastal mud.
• Pitcher plant: insectivorous — supplements nitrogen in poor soil.
• Banyan tree: aerial prop roots; can cover acres.

Animal adaptations:

• Camel: hump stores fat; long legs; can drink 40 L of water at once.
• Polar bear: thick fur, white camouflage, layer of blubber.
• Chameleon: changes colour for camouflage and communication.
• Octopus: 3 hearts, 9 brains (1 central + 8 in arms), blue blood (copper-based).

Largest, fastest, smallest facts:

• Largest animal: blue whale (up to 30 m, 180 tonnes).
• Largest land animal: African elephant.
• Tallest animal: giraffe (up to 5.5 m).
• Fastest land animal: cheetah (~110 km/h).
• Fastest bird (in level flight): peregrine falcon during dive (~390 km/h).
• Smallest bird: bee hummingbird (~5 cm).
• Smallest mammal: bumblebee bat.

Symbiosis examples:

• Mutualism (both benefit): bee + flower (pollination + nectar).
• Commensalism (one benefits, other unaffected): barnacles on whales.
• Parasitism (one benefits, other harmed): tapeworm in human.

Reproduction:

• Asexual: budding (yeast, hydra), binary fission (amoeba), spore formation (fungi, ferns).
• Sexual: most plants and animals. Fusion of male and female gametes.
• Vegetative propagation in plants: cutting (rose), grafting (mango), layering (jasmine).

Pollination:

• By wind (anemophily) — grasses.
• By insects (entomophily) — bees, butterflies. Bright flowers, scent, nectar.
• By birds (ornithophily) — hummingbirds.
• By water (hydrophily) — Vallisneria.

Fruit types:

• Simple: from one ovary — mango, plum.
• Aggregate: from many ovaries of one flower — raspberry, strawberry.
• Composite: from many flowers — pineapple, jackfruit.

Photosynthesis vs respiration:

• Photosynthesis: CO₂ + H₂O → glucose + O₂. Only in green plants, during daytime.
• Respiration: glucose + O₂ → CO₂ + H₂O + energy. All living cells, day and night.
• Net effect: plants are a CO₂ sink during daytime, net O₂ source.

India's biodiversity hotspots: Western Ghats, Eastern Himalayas, Indo-Burma, Sundalands (Nicobar). Together host ~7% of world's biodiversity in ~2.4% of land.