How do biotic factors

influence each other?

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Ecological Relationships

Biodiversity = the number of species in an

ecosystem

http://www2.warwick.ac.uk/about/environment/faqs/biodiversity.jpg

Territory = space claimed by an

individual organism

Ecological Equilibrium = state of “balance” in an

ecosystem

� � NICHE - Role of organism

in the ecosystem � NICHE DIVERSITY –

Number of niches in an ecosystem; often determined by abiotic factors

Ecological Relationships A niche is the

sum of all activities and relationships a species has

while obtaining and

using resources needed to

survive and reproduce

Abiotic = non-living

� � When species or

individuals “fight” for the same resources. � E.g., Food, shelter….

� KEYSTONE PREDATOR/SPECIES -

A predator that causes a large increase in diversity of its habitat.

Competition: The “fight” may be indirect … individuals may never

directly contact each other.

Two species with similar needs for

same limited resources cannot

coexist.

Losing a keystone species usually disrupts many

ecological relationships.

� � A primary consumer feeds on a producer.

Herbivory:

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� �  A consumer feeds on another consumer.

�  One benefits, the other dies)

Predation (Predator/Prey)

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A lion eating zebra.

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�  A long-term relationship where two species live closely together and at least one benefits directly from the relationship (the other benefits, is harmed, or it not affected at all).

Symbiosis:

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� � Both organisms benefit from the relationship. � Win-Win situation!

Mutualism:

http://tumi-educational-resources.org/Educational%20%20Videos.htm

Commensalism � One organism

benefits, the other one is unaffected.

� Win-Neutral relationship

Parasitism � One organism benefits, the other

one is harmed! � Win-Lose relationship � Parasites rarely kill their hosts…it

would require them to get another one!

� � Biological Magnification — Increasing

concentration of poisons in organisms in higher trophic levels in a food chain or web.

Ecological Relationships

Many toxins in the water

Many toxins in the person

� Biological Magnification- accumulation of increasing amounts of toxin within tissues of organisms.