Question #7828a

1 Answer
Nov 12, 2017

1) Biotic and abiotic factors together create and define the ecosystem.

2) Furthermore, these biotic and abiotic factors sometimes are mutually interactive and influence each other


1) An ecosystem is characterized by both its biotic and its abiotic factors.

For example, if two areas were exactly alike in terms of atmospheric temperature, altitude, insolation, and so on -- but differed only in the amount of rainfall each received, then the ecosystems that resulted would be vastly different -- a forest and a desert, say.

Definition of "insolation"

2) The biotic and the abiotic factors can influence each other because they are sometimes mutually interactive.

For example, the amount of sunshine clearly influences the growth of plants.

But this effect goes both ways:
The growth of plants modifies the amount of sunshine that reaches the ground.

Bare earth is colonized first by seedlings that can tolerate the effect of full sunshine beating on the ground. But as these seedlings grow, they shade the ground, making it less hospitable to their own seedlings and more hospitable to other species whose seedlings can tolerate shade.
This is one of the causes for new stages in ecological succession.

Another example of mutual influence concerns rainfall.
The amount of rain obviously impacts the type and amount of plant growth.

But the reverse is also true:
The presence of plants can influence the amount of rainfall in a couple of ways.

1) Plants draw up ground water and release it into the atmosphere by transpiration. Besides that, plants retain water near the surface, where it can be evaporated and added to atmospheric moisture.
The consequence of more atmospheric moisture is more rainfall.

2) In addition, according to Nature, "the darker surfaces of plants compared to sandy deserts also absorb more solar radiation, which, along with their rough texture, can create convection and turbulence in the atmosphere." This might create more — or less — rainfall.