It is the process by which an organism obtain its nourishment, the supply of nutrients required by its body and cells to stay alive.
Types: Autotrophic nutrition and Heterotrophic nutrition
Autotrophic Nutrition:
- Plant exhibit autotrophic mode
- They prepare their own food by the process of photosynthesis
- Also called self-nourishment
- These are of two types:
- Photosynthesis
6 CO2 + 6H2O C6H12O6 + 6O2
Radiant energy
Of sunlight and
chlorophyll
Occurs in all green plants
- Chemosynthesis
CO2 +H20 CARBOHYDRATES
Chemical nutrients
Sunlight is not used as an energy source
Used for energy in photosynthesis.
Heterotrophic Nutrition:
- Animals exhibit heterotrophic mode
- These are directly or indirectly dependent upon the autotrophs for their organic food
- They have no chlorophyll so these cannot trap the radiant energy of sunlight
- Types:
- Holozoic or helotrophic
Organism takes in whole food, i.e., whole plant or whole animal or their parts. The food ingested undergoes digestion, absorption and assimilation.
e.g.: small organisms like Amoeba and large organism like Human beings.
Depending upon source of food, they are differentiated into:
- Herbivores : Plant feeding. Example: Cow, Horse.
- Carnivorous: meat or animal eaters. Example: Lion, Tiger.
- Omnivorous: both plant and animal eaters. Example: Cockroach
- Cannibals: eat upon the member of their own species. Example: Snakes.
- Detritivores: feed upon dead organic matter in mud. Example: Earthworms.
- Predators: larger animal feed upon the smaller animal. Example: Eagle, kite.
- Insectivores: feed upon insects. Example: Frog, Lizards.
- Edentulous: ant-eaters. Example: Manis, Spiny ant-eater.
- Scavengers: feed upon dead and decaying animal or plant. Example: Vultures, Crow.
- Piscivorous: animals feeding upon fish. Example: Crocodiles.
- Grainivores: herbivores which feed upon the grains. Example: Rock pigeon.
- Saprophytic Nutrition
Organisms derive its nourishment from dead and decaying matter by releasing enzymes to digest the dead organic food and then the nutrients are absorbed through body surface.
Example: Fungi
- Osmotrophic Nutrition
Animals take predigested food materials by diffusion through their body wall. Example: Taenia solium
- Parasitic
Organism derives its nourishment from host organism either in liquid or solid form. Example: Taenia solium is a tape worm living in human intestine.
Types: Endoparasites: live inside the body of the host. Example: Taenia solium, Plasmodium vivax.
Ectoparasites: live in the outer surface of host and generally attach themselves during feeding. Example: Mosquitoes, lice, Bed bugs.
On the basis of foods size, animals are divides into:
Microphagous: animals take small sized food particles. Example: Earthworms.
If food is ingested in liquid form, called fluid-feeders. Example: Mosquitoes.
Macrophagous: animals take food from outside in form of large pieces. Example: Hydra.
