BIOLOGY
Aim: What shapes an ecosystem?
9-4
(A) CLIMATE
 Weather is the day to day condition of the Earth’s atmosphere at a certain time
and place
 Climate is the average yearly, condition of temperature and precipitation in a
region.
 What decides climate?
o Carbon dioxide and atmospheric gases trap heat energy and maintain the
Earth’s temperature. This trapping of the gases is known as the
greenhouse effect.
o Latitude: determines the climate. There are three main climate zones:
Polar, Temperate, and Tropical
(B) ECOSYSTEMS
 Ecosystems are made up of biotic (living) and abiotic (nonliving) things.
 Together, they determine the survival and growth of an organism and the
productivity of the ecosystem.
 Habitat: where an organism lives
 Niche: the way an organism uses all the biotic and abiotic things in its
habitat. Ex: what it eats, how it gets food….
(C) COMMUNITY INTERACTIONS
 The way communities interact with other organisms as well as the environment
greatly affect ecosystems.
o 1—COMPETITION: using the same resources—usually results in one
organism dying out
o 2—PREDATION: one organism captures and eats another
o 3—SYMBIOSIS: two species live close together in one of three ways:

Mutualism: both organisms benefit from the relationship
In the picture above, the fish is cleaning the mouth
of the eel getting food. The eel is benefiting in that
its mouth is being cleaned of potential dangers.

Commensalism: one organism benefits while the other is not
affected.
The clownfish benefits in that it is protected
from other fish and the anemone is not
affected.

Parasitism: one organism benefits while the other is harmed.
The tick is benefiting in that it is getting food,
but the host is being harmed in that it will become
Sick.
(D) Changing Communities
 Different populations that live together affect one another
 An ecosystem that remains unchanging is said to be a stable ecosystem
 After a profound change in an ecosystem (for example: forest fire) ecological
succession occurs.
 Ecological succession: slow changes that occur in an area until a stable community
is reached
 Succession may also occur when an entirely new environment appears
BASICALLY, FROM NOTHING COMES SOMETHING.