MEANING AND TYPES
OF NUTRITION
Nutrition
is the process of feeding and utilization of
food for energy provision, growth, development, repair and maintenance of the
overall body health. Nutrition can also refer to the study of the relationship
between diet, health and diseases, there are two major types of nutrition based
on how organisms obtain their food
AUTOTROPHIC NUTRITION
Autotrophic nutrition is a type of nutrition whereby organisms manufacture their own food using energy source available to them. An organism that manufactures its own food is called an autotroph, the term ‘autotroph’ comes from the Greek word ‘autos’ which mean ‘self’ and ‘trophy’ which mean ‘feed’;
hence ‘ autotrophy’ means ‘self-feeding’ this means that autotrophs are organism that are capable of making their own food for their own use and for other organisms, they are very important because without them no other organisms could exist or survive, example of autotrophic organism include green plants, algae and some bacterial such as cyanobacterial
HETEROTROPHIC NUTRITION
Heterotrophs are organism that cannot make their own food and hence are incapable of self-feeding, the term ‘hetero’ means different and ‘trophy’ means feeding, therefore, ‘heterotroph’ mean ‘different feeding.
Heterotrophs
feed on either different food substance manufactured by other organisms or feed
on other organism directly, example of heterotrophs include all animals, fungi,
most bacteria, and protectants, the mode of feeding in which an organism is
unable to make its own food and instead depends on food already made by other
organism is called heterotrophic nutrition and there are various types of
heterotrophic nutrition including holozoic, saprophytic and symbiotic nutrition
HOLOZOIC NUTRITION
This
mode of nutrition involves taking in complex food substances, digesting,
absorbing and assimilating the nutrients into the organisms’ body. The
undigested and indigestible food remain area final egested as faeces, this
types of nutrition is found in most animal, Holozoic nutrition is divided into
three modes of feeding carnivorous, herbivorous and omnivorous
SAPROPHYTIC NUTRITION
This
is a mode of feeding in which an organism feeds on decaying organic matter,
such decaying matter may originate from plants, animals and other decomposing
materials , organisms that obtain their food from dead and decaying organic
matter are called saprophytes releases digestive enzymes externally on the
substrate, the released enzymes convert organic molecules such as starch into
simple molecules such as glucose, the glucose can be easily absorbed by body
cells and used for various activities
SYMBIOTIC NUTRITION
This
is the feeding relationship between two species in which one or both benefit
from the relationship, symbiosis can be in the form of commensalism, mutualism
or parasitism