Abiotic and biotic factors

• define range and abundance of a species.

• Populations can only live in those areas where the favourable parts of the environmental gradients overlap

• Interaction of several factors, rather than a single factor, determines species distribution.

• “biodiversity hotspot”

Adaptation and Natural Selection

Adaptation -physical or behavioral trait that helps a plant or animal survive in its habitat.

Two types of adaptation:

• Acclimation - changes in an individual organism due to non-permanent physiological modifications

• Evolution - gradual changes in a species due to changes in genetic material and competition

Natural selection -according to Darwin's theory, the organisms best adapted to their environment tend to survive and while less adapted tend to be eliminated.

Theory of evolution - developed by Charles Darwin and Alfred Wallace.

Habitat &

Ecological Niche

Habitat - the place or set of environmental conditions in

which a particular organism lives

Ecological niche - the role played by a species in a biological community

Niche defines:

- way of obtaining food;

- relationships w /other species

- services to the community.

Competition

for the resources causes

Resource

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