Nutrition.

Is the process by which an organism provides itself or is provides itself or is provided with materials  necessary for energy release, growth and repair of body tissues and keeping the body in a good condition.



Nutrition is the process by which organisms take in and use nutrients.

Nutrients are any substances that nourish an organism.

FOOD

Is any liquid or solid which provides the body with materials for growth and repair,  energy release or keeping the body in a good (healthy) condition.

Food is any material when taken in absorbed and utilized meet requirement of plant and animal body.



FUNCTION OF FOOD

1. Oxidized to release energy
2. Used in growth of cells
3. Used to repair lost cells and tissue


KINDS OR MODES OF NUTRITION

Basically there are two kinds of nutrition

1. AUTOTROPHIC NUTRITION

2. HETEROTROPHIC NUTRITION

                                    AUTOTROPHIC NUTRITION

This is mode of nutrition where by organisms can make their own food from simple inorganic substance, such as carbon dioxide and water using either light energy (photosynthesis) or chemical energy (chemosynthesis). Organisms which feed by this way are known as AUTOTROPHS

            Example

            1. Green plants

          2. Iron bacteria and Sulphur bacteria

 

                                   HETEROTROPHIC NUTRITION

This is the mode of nutrition where by organisms use organic materials as the only source of food. Organisms which feed by this way are known as HETEROTROPHS. They feed on already made food.

There are three types of heterotrophic nutrition

  1. Saprophytic nutrition
  2. Symbiotic nutrition
  3. Holozoic nutrition

 

  1. Saprophytic nutrition

This is the mode of nutrition where by organisms feed on dead decaying bodies parts of animals or their excrete; Organisms feeding by this way are known as SAPROPHYTES



      2. Holozoic nutrition

This is mode of nutrition where by organism take food by mouth. It passes through a digestive system and broken down, finally absorbed into body tissue.


FORMS OF HOLOZOIC NUTRITION

1. Herbivores – Are animals which feed on plants only Example cow, goat and zebra       

2. Carnivores – Are animals which feed on flesh only e.g. lion, tiger.

3. Omnivores – Are animals which feed on varieties o food (flesh, plants, insect etc) example. Man, monkey, pig.

4. Insectivores – Are animals that feed on insects e.g. shrews, ant


      3. Symbiotic nutrition

This mode of nutrition in which an organism of different species exist in a nutrition relationship with other organism;

 

There are three kinds of symbiotic associations

  1. Mutualism
  2. Commensalism
  3. Parasitism.

 

  1. Mutualism

This is a nutritional relationship in which the two partners benefit each other by living together Example Nitrogen Fixing Bacteria in the roots of legumes.

      2. Commensalism

This is an association of two group where by the host does not get any partnership. Example Epiphytes (are plants that grow on other plants) e.g. Moses and algae which grow on upper parts of big trees to get sunlight easily

 
      3. Parasitism

This is a nutritional relationship between two organisms in which one organism live inside/on other living organism and depends on food. The parasite causes harm to the host. The host provides food and shelter for the parasite.

Endoparasites are living inside the body of the host e.g. tapeworm, roundworm and plasmodia.

Ectoparasites are parasite that lives on host’s surface [outside the body] examples includes some mites, flea and body lice.

The importance of nutrition

  1. Nutrition enables an organism to get nutrients and energy required for various life processes. These processes include growth and development of cells.
  2. To protect body against diseases.
  3. Enable in replacement of worn out tissue and dead cell.