Taxonomy: Classification of Organism Notes with PDF

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Biology Fact Compendium

Microorganisms

• Bacteria
  • Prokaryotic (no true nucleus).
  • Size: 2-4 microns (visible with a compound microscope).
  • Not borderline organisms (living/non-living, etc.).
  • Can be cultured in an artificial/synthetic medium.
  • Nutritional Modes:
    • Autotrophs: Synthesize own food via photosynthesis (using pigments, not chloroplasts) or chemosynthesis.
    • Heterotrophs: Saprobes (consume dead matter) or parasites.
  • Beneficial bacteria in the human gut produce vitamins like biotin and vitamin K.
• Viruses
  • Cannot be cultured in a synthetic medium; require a living host cell.
• Mycoplasma
  • Smallest organism capable of autonomous growth and reproduction.

Animal Kingdom: Classification & Characteristics

• General Traits
  • Warm-blooded animals (Birds & Mammals): Maintain constant body temperature via homeostasis.
  • Reproduction:
    • Asexual (Fission): e.g., Amoeba.
    • Viviparous: Give birth to live young (e.g., most mammals).
    • Oviparous: Lay eggs.
  • Respiration: Some animals (e.g., Hydra) respire via diffusion without a circulatory system.
• Phylum Echinodermata
  • Examples: Starfish, sea urchins, sand dollars, sea cucumbers.
  • Symmetry: Five-point radial symmetry.
  • Reproduction: Mostly oviparous.
• Phylum Chordata: Fishes
  • True Fish: Catfish, Seahorse, Hagfish.
  • Not True Fish:
    • Starfish (Echinoderm)
    • Jellyfish (Cnidarian)
    • Silverfish (Insect)
    • Crayfish (Crustacean)
    • Sea cow, Sea lion (Mammals)
  • Cartilaginous Fishes (e.g., Sharks, Rays):
    • Skeleton made of cartilage.
    • Internal fertilization.
  • Bony Fishes: Usually have a swim bladder.
• Mammals (Mammalia)
  • Whales are mammals, not fish. They are the largest mammals.
    • Blue Whale: Largest animal ever known.
    • Sperm Whale: Largest toothed whale.
  • Monotremes: Egg-laying mammals (e.g., Echidna/spiny anteater).
  • Flying Mammal: Bat (only mammal capable of true flight).
  • Aquatic/Semi-Aquatic Mammals:
    • Dolphins, Sea Cows (Dugongs), Sea Lions, Seals, Otters.
    • Ganga River Dolphin is India’s national aquatic animal.
  • Bears: Panda (bear family), Sloth Bear (commonly seen performing).
  • Canines: Dingo (wild dog unable to bark).
• Amphibians (Amphibia)
  • Cold-blooded vertebrates; name means “both land and water.”
  • Three-chambered heart (two atria, one ventricle).
  • Frogs:
    • Cold-blooded.
    • Breathe through skin and lungs.
    • The intestine shortens during metamorphosis for a carnivorous diet.
• Reptiles (Reptilia)
  • Crocodilians: Gharial (found in the Ganga River); have a four-chambered heart.
  • Others: A Tortoise is a reptile.
• Apes and Primates
  • Apes (e.g., Gibbons, Gorillas, Orangutans, Chimpanzees): No tails.
    • Gibbons are “lesser apes.”
    • Gorillas, Chimpanzees, and Orangutans are “great apes.”
  • Monkeys (e.g., Langur): Have tails.
• Birds (Aves)
  • Examples: Crow, Eagle, Parrot, Penguin.
  • A bat is a mammal, not a bird.
• Animal Behavior & Defense
  • Roll for defense: Hedgehog (spiky ball), Pangolin (scaly ball).
  • Does not roll: Marmot (hides in burrows).
• Animal Intelligence & Communication
  • Taught language with some success: Chimpanzees, Parrots, Dolphins.
  • Not successfully taught: Dogs.

Animal Physiology & Anatomy

• Circulatory System (Hearts)
  • Two-chambered: Fish (Pisces).
  • Three-chambered: Amphibians (e.g., frogs), most reptiles.
  • Four-chambered: Mammals (e.g., monkeys), birds, and crocodiles (reptile exception).
• Digestive System (Gallbladder)
  • Absent in: Rat, Camel, Giraffe, Deer, Horse, Zebra, Elephant, Rhinoceros, some birds, and fish.
  • Present in: Musk deer (exception).
• Limbs and Locomotion
  • Hoofed animals: Deer, Zebra, Horse.
  • Non-hoofed: Jackal (has nails).
  • Limbless reptiles: Snakes.

Specific Animal Groups & Species

• Mammals
  • Nilgai: Largest Asian antelope (deer family). Scientific name: Boselaphus tragocamelus.
  • Asiatic Wild Ass: Scientific name: Equus hemionus.
  • Barasingha: Scientific name: Cervus duvauceli.
  • Chinkara: Scientific name: Gazella bennetti.
• Birds
  • Kiwi: Flightless bird found only in New Zealand.
  • White Leghorn: Variety of fowl known for high egg production.
• Invertebrates
  • Molluscs:
    • Octopus (also called devilfish).
    • Squid (the largest invertebrate).
  • Arachnids (Spiders, Scorpions, Mites, Ticks):
    • Two body parts, eight legs, no wings/antennae.
    • Spider silk is called Gossamer silk.
  • Insects & Others:
    • Silverfish: Wingless insect.
    • Termites: Social insects (scientific name Isoptera), called White ants.
    • Glow-worm: Light-producing insect.
    • Crab: Crustacean, not an Arachnid.

Insects & Arachnids: Detailed Facts

• Silkworm & Silk
  • Silk fiber is produced during the pupa stage.
  • Cocoon is made of a single, continuous strand about 1.5 km long.
  • Silkworm (Bombyx mori) feeds exclusively on Mulberry leaves.
• Physiology & Behavior
  • Cockroach: Has colorless blood (no hemoglobin); respires via a tracheal system.
  • Mosquito: Only females suck blood; males feed on plant juices.
  • Ants: Secrete Formic acid.
  • Spiders: Some exhibit sexual cannibalism (female eats male after mating).
  • Lac: Secretion from the lac insect (Kerria lacca).
• Worms
  • Tapeworms: Hermaphrodites.
  • Roundworms (Nematodes): Have separate sexes. Includes parasites causing Filaria and Guinea worm.

Snakes

• Unique Behavior: King Cobra is the only snake that builds a nest (it is oviparous) and guards its eggs. Its primary diet is other snakes.
• Venom: Cobra venom is primarily neurotoxic. Pythons are non-venomous constrictors.
• Anatomy: Poisonous fangs are modified Maxillary teeth. The poison gland is homologous to the salivary gland of vertebrates.
• Reproduction: Most snakes are oviparous, but some (e.g., Green Anaconda) are viviparous.

Animal Types & Adaptations

• Feeding Strategies:
  • Detritivores: Consume dead matter (e.g., Earthworms, Millipedes).
  • Filter Feeders: Strain food from water (e.g., Oysters, Clams, Whales).
• Activity Patterns: Nocturnal animals (e.g., Mosquito, Bat, Owl).
• Physiological Adaptations:
  • Camel: Stores water in its intestine.
  • Kangaroo rat: Excretes highly concentrated urine.
• Diet:
  • Carnivores: Dog.
  • Herbivores: Dugong (marine mammal), Parrotfish (fish).

Plants: Types & Habitats

• Based on Growing Surface:
  • Lithophytes: Grow on rocks (e.g., Nepenthes khasiana).
  • Epiphytes: Grow on other plants for support only (e.g., Orchids).
• Based on Nutrition:
  • Insectivorous: Derive nutrients from insects (e.g., Pitcher Plant/Nepenthes). They are autotrophs, not parasites. The pitcher is a modified leaf.
  • Parasites: Stem parasite (e.g., Cuscuta), Root parasite (e.g., Sandalwood/Chandan).
  • Saprotrophs: Derive nutrition from dead matter (e.g., Fungi).
• Based on Habitat:
  • Xerophytes: Adapted to dry climates (e.g., Cactus, Opuntia); often have long taproots.
  • Hydrophytes: Aquatic plants.
  • Halophytes: Grow in saline conditions (e.g., mangroves).

Plant Anatomy & Edible Parts

• Buds: Clove is a dried flower bud.
• Modified Stems (have nodes & internodes):
  • Rhizome: Ginger, Turmeric.
  • Tuber: Potato.
  • Bulb: Onion (edible fleshy leaves), Garlic.
  • Corm: Jimikand/Suran (Elephant Foot Yam).
  • Sugarcane is a stem.
• Modified Roots:
  • Sweet Potato, Carrot, Radish, Turnip.
• Fruits:
  • True Fruit: Develops from ovary (e.g., Grape, Mango, Plum).
  • False Fruit: Develops from ovary plus other parts (e.g., Apple, Cashew).
  • Ladies Finger (Okra) is a fruit (capsule).
  • Fruit Types: Lychee (drupe), Mulberry (sorosis).
• Other Plant Parts:
  • Saffron: Derived from the stigma and styles of the Crocus flower.
  • Coconut’s edible part is the endosperm.

Plant Products & Chemistry

• Fibres:
  • From stems: Sunn, Hemp, Jute.
  • From fruit: Cotton (composed of ~91% cellulose). Types: Lint and Fuzz.
• Pigments:
  • Red: Apple (Anthocyanin), Tomato (Lycopene).
  • Yellow/Orange: Papaya (Caricaxanthin), Carrot (Beta-Carotene).
• Chemical Compounds:
  • Garlic odour: Sulfur compounds.
  • Onions cause tearing: Sulfenic acid.
  • Chilli pungency: Capsaicin (C₁₈H₂₇NO₃).
  • Fruit sweetness: Fructose.
• Other Products:
  • Opium: Obtained from the latex of the unripe capsule of Papaver somniferum (Opium Poppy). It is a depressant. Derivatives include Morphine, Heroin, and Noscapine.

Fungi, Lichens, and Symbiosis

• Fungi: Examples include Yeast, Moulds, Mushrooms.
• Symbiotic Relationships:
  • Mycorrhiza: Fungi + roots of higher plants.
  • Lichens: Fungi + algae/cyanobacteria (a mutualistic relationship). They are pioneer species.
  • Nitrogen Fixation: Symbiotic bacteria (e.g., Rhizobium) in root nodules of legumes.
  • Cnidarians: Can form symbiosis with algae (e.g., corals).

Ecology & Biodiversity

• Species Richness: Insects (Class Insecta) form the largest identified group of species.
• Trophic Levels:
  • Level I: Producers/Autotrophs (e.g., plants, cyanobacteria).
  • Primary Consumers: Herbivores.
  • Secondary Consumers: Carnivores/Omnivores.
  • Decomposers: Saprotrophs.
• Aquatic Life:
  • Fish survive in frozen lakes because only the top layer freezes.
  • Fish use gills to extract oxygen from water and die out of water.
• Human Species: Chinese, American, Indians, and Black Africans all belong to the same species, Homo sapiens.

Discoveries & Miscellaneous

• New Species: A new banana species (Musa indandamanesis) was discovered in the Little Andaman Islands.
• Forensic Science: Diatoms are used to diagnose death by drowning.
• Man-Made Plants: Triticale is a lab-made cereal from Wheat and Rye.
• Plant Hormones: Cytokinin can help break seed dormancy.
• Biofertilizers: The most suitable for sugarcane is Acetobacter diazotrophicus.

Know More About Taxonomy: Classification of Organism:

• Taxonomy: Classification of Organism – Old Year Questions
• Taxonomy: Classification of Organism One Liner Questions & Answers