BIO 102: GENERAL BIOLOGY II
NUTRITION
Nutrition in animals is as important as it is for plants. Plants prepare their own food by the
process of photosynthesis but animals cannot prepare their own food, hence they need to depend
on plants or other animals for their food.
Animals derive their nutrition either by eating plants directly (herbivores), or indirectly by eating
animals which have consumed plants (carnivores). Some animals feed on both plants and
animals; these animals are termed omnivores. All organisms require food for their survival and
growth.
Nutrition is the biochemical and physiological process by which an organism uses food to
support its life. It provides organisms with nutrients, which can be metabolized to
create energy and chemical structures. Failure to obtain sufficient nutrients causes malnutrition.
The type of organism determines what nutrients it needs and how it obtains them. Organisms
obtain nutrients by consuming organic matter, consuming inorganic matter, absorbing light, or
some combination of these. Some can produce nutrients internally by consuming basic elements,
while some must consume other organisms to obtain pre-existing nutrients. All forms of life
require carbon, energy, and water as well as various other molecules.
Nutrients are substances that provide energy and physical components to the organism, allowing
it to survive, grow, and reproduce. Nutrients can be basic elements or complex macromolecules.
Approximately 30 elements are found in organic matter, with nitrogen, carbon,
and phosphorus being the most important. Macronutrients are the primary substances required by
an organism, and micronutrients are substances required by an organism in trace amounts.
Organic micronutrients are classified as vitamins, and inorganic micronutrients are classified
as minerals.
Mode of Nutrition: on the basis of mode of acquiring food
1. Autotrophic mode of nutrition:
It is also known as holophytic mode (plant like nutrition). Organisms can synthesize all the
essential nutrients required for them from inorganic substrates (CO2, NH3, nitrates, water
etc) present in the environments. It is of two types.
i) Phototropic nutrition: Organisms synthesize their food in the presence of sun light using
Carbon-dioxide and water as substrate. Such organisms are known as Photo-Autotrophs. Eg.
Green plants
ii) Chemotropic nutrition: Organisms synthesis their organic food by the chemical reactions
(Oxidation) utilizing inorganic substrates like nitrates, Hydrogen sulphate, iron etc. such
organisms are known as chemo-autotrophs. Eg. Sulphur bacteria, Nitrobacter, Nitromonas.
2. Heterotropic mode of nutrition:
organisms cannot synthesize their food by themselves rather they depend on the food
prepared by Autotrophs (directly or indirectly). Such organisms are known as heterotrophs.
According to the types of food or mode of feeding, heterotropic nutrition are of following types
, i) Holozoic nutrition: it is known as animal-like mode of nutrition. In this mode, animals feed
on plants or other animals whole or their parts for food. Such animals are free living and have the
characteristics of Ingestion, digestion, absorption, assimilation and egestion. Such animals are
classified into following types
Herbivorous: Animals which feed on plants for nutrition. Eg. Cow , goat, buffalo etc
Carnivorous: Animals which feed on other animals or animal products. Eg. Tiger, lion
Omnivorous: Animals having mixed diets (feeding on both animals and plants and their
products). Eg. Human, crow
Coprophagous: Animals feeding upon faeces of other animlals. Eg. Pig, some insect spp
Cannibalism: Animals feeding upon smaller animals of same species. Eg. Snakes, frog
Sanguivorous: Animals feeding upon blood. Eg. Leech, Vampire bat, female mosquito
ii) Saprotrophic nutrition: organisms obtain their nutrition from dead and decaying organic
matter. They are decomposers. Eg. Fungi, bacteria, earthworm etc. They includes saprophytes
and saprozoic.
iii) Symbiotic nutrition: In symbiosis two or more organisms of different species live together
in close association. Nutrition involved in symbiotic association are
Parasitism: One partner (parasite) depend completely upon other partner (Host) for
nutrition. Parasites living outside host body known as ecto-parasites Eg. Leech, ticks etc.
and those parasites living inside host body known as endoparasites. Eg. Plasmodium,
Taenia solium.
Mutualism: both partner organisms get benefit from each other. Eg. Lichen, Rhizobium on
root nodules of legumes.
Commensalism: one partner gets benefit which other neither harmed or benifited. Eg.
Cattle egret, Whale and Barnacle.
Types of Nutrition in Animals
The different types of nutrition in animals include:
1. Filter Feeding: obtaining nutrients from particles suspended in water. Commonly used
by fish.
2. Deposit feeding: obtaining nutrients from particles suspended in the soil. Earthworms
use this mode of ingestion.
3. Fluid feeding: obtaining nutrients by consuming other organisms’ fluids. Honey bees,
and mosquitos exhibit this mode of food intake.
4. Bulk feeding: obtaining nutrients by eating the whole of an organism. Example: Python.
5. Ram feeding and suction feeding: ingesting prey via the surrounding fluids. This mode
of ingestion is usually exhibited by aquatic predators such as bony fish.
Process of Nutrition in Animals
The process of nutrition in animals involves the following steps:
NUTRITION
Nutrition in animals is as important as it is for plants. Plants prepare their own food by the
process of photosynthesis but animals cannot prepare their own food, hence they need to depend
on plants or other animals for their food.
Animals derive their nutrition either by eating plants directly (herbivores), or indirectly by eating
animals which have consumed plants (carnivores). Some animals feed on both plants and
animals; these animals are termed omnivores. All organisms require food for their survival and
growth.
Nutrition is the biochemical and physiological process by which an organism uses food to
support its life. It provides organisms with nutrients, which can be metabolized to
create energy and chemical structures. Failure to obtain sufficient nutrients causes malnutrition.
The type of organism determines what nutrients it needs and how it obtains them. Organisms
obtain nutrients by consuming organic matter, consuming inorganic matter, absorbing light, or
some combination of these. Some can produce nutrients internally by consuming basic elements,
while some must consume other organisms to obtain pre-existing nutrients. All forms of life
require carbon, energy, and water as well as various other molecules.
Nutrients are substances that provide energy and physical components to the organism, allowing
it to survive, grow, and reproduce. Nutrients can be basic elements or complex macromolecules.
Approximately 30 elements are found in organic matter, with nitrogen, carbon,
and phosphorus being the most important. Macronutrients are the primary substances required by
an organism, and micronutrients are substances required by an organism in trace amounts.
Organic micronutrients are classified as vitamins, and inorganic micronutrients are classified
as minerals.
Mode of Nutrition: on the basis of mode of acquiring food
1. Autotrophic mode of nutrition:
It is also known as holophytic mode (plant like nutrition). Organisms can synthesize all the
essential nutrients required for them from inorganic substrates (CO2, NH3, nitrates, water
etc) present in the environments. It is of two types.
i) Phototropic nutrition: Organisms synthesize their food in the presence of sun light using
Carbon-dioxide and water as substrate. Such organisms are known as Photo-Autotrophs. Eg.
Green plants
ii) Chemotropic nutrition: Organisms synthesis their organic food by the chemical reactions
(Oxidation) utilizing inorganic substrates like nitrates, Hydrogen sulphate, iron etc. such
organisms are known as chemo-autotrophs. Eg. Sulphur bacteria, Nitrobacter, Nitromonas.
2. Heterotropic mode of nutrition:
organisms cannot synthesize their food by themselves rather they depend on the food
prepared by Autotrophs (directly or indirectly). Such organisms are known as heterotrophs.
According to the types of food or mode of feeding, heterotropic nutrition are of following types
, i) Holozoic nutrition: it is known as animal-like mode of nutrition. In this mode, animals feed
on plants or other animals whole or their parts for food. Such animals are free living and have the
characteristics of Ingestion, digestion, absorption, assimilation and egestion. Such animals are
classified into following types
Herbivorous: Animals which feed on plants for nutrition. Eg. Cow , goat, buffalo etc
Carnivorous: Animals which feed on other animals or animal products. Eg. Tiger, lion
Omnivorous: Animals having mixed diets (feeding on both animals and plants and their
products). Eg. Human, crow
Coprophagous: Animals feeding upon faeces of other animlals. Eg. Pig, some insect spp
Cannibalism: Animals feeding upon smaller animals of same species. Eg. Snakes, frog
Sanguivorous: Animals feeding upon blood. Eg. Leech, Vampire bat, female mosquito
ii) Saprotrophic nutrition: organisms obtain their nutrition from dead and decaying organic
matter. They are decomposers. Eg. Fungi, bacteria, earthworm etc. They includes saprophytes
and saprozoic.
iii) Symbiotic nutrition: In symbiosis two or more organisms of different species live together
in close association. Nutrition involved in symbiotic association are
Parasitism: One partner (parasite) depend completely upon other partner (Host) for
nutrition. Parasites living outside host body known as ecto-parasites Eg. Leech, ticks etc.
and those parasites living inside host body known as endoparasites. Eg. Plasmodium,
Taenia solium.
Mutualism: both partner organisms get benefit from each other. Eg. Lichen, Rhizobium on
root nodules of legumes.
Commensalism: one partner gets benefit which other neither harmed or benifited. Eg.
Cattle egret, Whale and Barnacle.
Types of Nutrition in Animals
The different types of nutrition in animals include:
1. Filter Feeding: obtaining nutrients from particles suspended in water. Commonly used
by fish.
2. Deposit feeding: obtaining nutrients from particles suspended in the soil. Earthworms
use this mode of ingestion.
3. Fluid feeding: obtaining nutrients by consuming other organisms’ fluids. Honey bees,
and mosquitos exhibit this mode of food intake.
4. Bulk feeding: obtaining nutrients by eating the whole of an organism. Example: Python.
5. Ram feeding and suction feeding: ingesting prey via the surrounding fluids. This mode
of ingestion is usually exhibited by aquatic predators such as bony fish.
Process of Nutrition in Animals
The process of nutrition in animals involves the following steps:
