Unit 5 – Ecosystems
I. Living Things and Their Environment
A. Ecosystems
1. All ____________ and _____________ things in an area
2. Ecology – study of interactions between organisms
3. Ecosystems can vary in size (small – __________
_____________; large – __________desert)
4. Abiotic parts
a. ____________________ parts of an ecosystem
b. parts include: _______________, ______________,
_____________, _______________, _____________________
and _________________
c. biotic parts need abiotic parts to live (plants need sun;
animals need air)
5. Biotic parts
a. living organisms in an ecosystem
b. parts include: __________________, fungi, ___________,
bacteria
B. Populations and Communities
1. A group of organisms of the same ______________________ in
an ecosystem is called a population.
2. Savanna ecosystem contains populations of gazelles, lions,
grasses, trees
3. A __________________________ is all the populations that live
and __________________ in an area.
4. Populations need:
a. ______________________ and water
b. shelter
c. ______________ to _______________.
5. Organisms compete to meet their needs.
6. Stronger organisms get the most ____________ and take the best
___________.
7. Weaker individuals may not ______________________.
8. There is only enough food, water, etc. to support a certain number
of organisms, so we call these resources ____________________
factors.
C. Niches
1. An organism’s ________________ is the place where it lives within
an ecosystem.
2. Many populations can live in the same ecosystem.
3. An organism’s niche is its _______________, or function, in its
ecosystem.
4. An organism’s niche includes:
a. how it finds ____________
b. the climate it _____________ in
c. what types of food it eats
5. Every ________________ has a niche.
6. Each population has its own niche. No two are exactly the same!
D. Diversity
1. Diversity is the variety of different ______________ that live in an
ecosystem.
2. Ecosystems close to the _______________ usually have a lot of
diversity.
3. Importance of diversity
a. Organisms rely on other _____________________.
b. Relationships are connected in a large, complex __________
c. More organisms supply more resources.
4. Natural reasons for diversity
a. ________________
b. ________________
5. Humans affect diversity in several ways.
a. Can damage ecosystems
b. ______________________ can reduce the number of
species
c. Destruction of forests in order to build _____________