Friday, 10 June 2011

Heterotrophic Nutrition

Heterotrophic Nutrition

Heterotrophic nutrition is the nutrition of organisms which need ready made complex organic molecules, they obtain these wither directly from plants, or from organisms which have fed on plants. Thus heterotrophic organisms are the consumers in an ecosystem.


Organism that carry out heterotrophic nutrition are called heterotrophs
 
 
 
 
Holozoic Nutrition

Involves feeding by ingesting complex organic matter which are then digested and absorbed


Example of organisms with holozoic nutrition are animals and insectivorous plants




Sapropytism

Feed on the dead remains of other organisms(dead organic material).


Secrete enzymes onto the food, then soluble products are absorbed

Involves feeding by absorbing their required nutrients from dead organic matter.

Extracellular digestion.

Responsible for decay.

The decomposers in an ecosystem.

Fungi such as Rhizopus are saprobionts. Bacteria and fungi like musrooms, yeast and Mucor (bread mould)
 
 
 
 
 
 
 
 
 


 
Parasites

Obtain food from another living organism, the host


There is a close association between the host and the parasite

The host suffers some degree of harm.

Taenia, the pork tapeworm, is a parasite, the adult is an endoparasite of human beings, thus we are the primary host, it is found attached to the wall of the small intestine of an infected individual, where it absorbs the soluble products of digestion.

Adaptations

Large surface area for absorption

No alimentary canal

Thick outer covering (tergument)

Suckers and hooks for attachment to gut wall, to resist peristalsis

Large numbers of offspring produced

Reduced nervous system

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