Heterotrophs cannot synthesise their own nutrients.
They depend on other sources for the supply of nutrients including those
required for energy production. Most of the bacteria, all fungi and all animals are
heterotrophs.
You
might have seen packets of mushrooms sold in the vegetable
market.
You may have also seen fluffy umbrella-like patches growing on rotting wood
during the rainy season. Let us find out what type of nutrients they need to
survive and from where they get them.
These
organisms are called fungi.They have a different mode of nutrition. They
secrete digestive juices on the dead and decaying matter and convert it into a
solution. Then they absorb the nutrients from it.
This
mode of nutrition in which organisms take
in nutrients in solution form from dead and decaying matter is called
saprotrophic nutrition.
Plants
which use saprotrophic mode of nutrition are called saprotrophs.
The
fungal spores are generally present in the air. When they land on
wet
and warm things they germinate and grow. Now, can you figure out how we can
protect our things from getting spoiled?
Some
organisms live together and share shelter and nutrients. This is
called
symbiotic relationship. For example, certain fungi live in the roots
of
trees. The tree provides nutrients to the fungus and, in return, receives help from
it to take up water and nutrients from the soil. This association is very important
for the tree.
Some of the bacteria and of fungi depend on other
dead organisms to obtain nutrients. Those which live on other organisms,
decompose and degrade the complex molecules present in these organisms to
simple molecules.
Bacteria and fungi absorb these molecules through
their body surface. These are called saprophytes. In this process, they add
several valuable nutrients to the medium in which they live(water or soil).
HERBIVORES, CARNIVORES AND OMNIVORES:
All the animals are heterotrophic in their
nutrition. They cannot synthesise their own food material. Hence, they consume other organisms such as plants,
animals and microorganisms.
Size and nature of food consumed is different in
different animals.
They may consume either small microscopic or large
plants or animals or both.
Animals consuming plants as food are called
herbivores. Those consuming other animals are called carnivores.
Those which consume both animals and plants are called omnivores.
Interestingly, some plants are also carnivorous
especially insectivorous (feed on insects). They supplement their
autotrophic nutrition by obtaining
nitrogen rich nutrients from the
insects.
Nepenthes, Dionea (Venus fly trap), Drosera (sun dew
plant) and Utricularia ( bladder wort) are some of the examples for this type
of plants. All these plants are autotrophic and can live by themselves without
feeding on insects. However, their growth is stimulated when they feed on
insects.
THANKYOU,
No comments:
Post a Comment