2. Chapter 3 Communities, Biomes,
and Ecosystems
Section 1: Community Ecology

3. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Communities
A biological community is a group of interacting populations that occupy the same area at the same time.
Oasis

4. Not every community includes the same variety of organisms.
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Communities
Therefore, your community also includes plants, other animals, bacteria, and fungi.
Not every community includes the same variety of organisms.
An urban community is different from a rural community and a desert community is different from an arctic community

5. Organisms adapt to the conditions in which they live.
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Communities
Organisms adapt to the conditions in which they live.
Depending on which factors are present, and in what quantities, organisms can survive in some ecosystems but not in others.

6. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Limiting Factors
Any abiotic factor or biotic factor that restricts the numbers, reproduction, or distribution of organisms is called a limiting factor.
Aboitic factors includes sunlight, climate, temperature, water, nutrients, fire, soil chemistry, and space.
Biotic limiting factors include living things, such as other plant and animal species.

7. Temperature also might be a limiting factor.
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Limiting Factors
Factors that restrict the growth of one population might enable another to thrive.
For example, in the oasis, water is limiting factor for all of the organisms.
Temperature also might be a limiting factor.
Desert species must be able to withstand the heat of the Sun and the cold temperatures of desert nights.

8. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Range of Tolerance
An upper limit and lower limit that define the conditions in which an organism can survive
For example, steelhead trout live in cool, clear coastal rivers and streams from California to Alaska.
The ideal range of water temperature for steelhead trout is between 13ºC and 21ºC.

9. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Range of Tolerance
However, steelhead trout can survive water temperatures from 9ºC to 25ºC.
At these temperatures, steelhead trout experience physiological stress, such as inability to grow or reproduce.
They will die of the water temperature goes beyond the upper and lower limits.

10. 3.1 Community Ecology Range of Tolerance Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Range of Tolerance

11. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Range of Tolerance
The ability of any organism to survive when subjected to abiotic factors or biotic factors is called tolerance.
That is, the range of tolerance of water temperature for steelhead is 9ºC to 25ºC.
Notice the greatest number of steelhead live in the optimum zone in which the temperature is best for survival.

12. At these temperatures, there are fewer fish.
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Range of Tolerance
Between the optimum zone and the tolerance limits lies the zone of physiological stress.
At these temperatures, there are fewer fish.
Beyond the upper tolerance limit of 25ºC and the lower tolerance limit of 9ºC, there are no steelhead trout.
Therefore, water temperature is a limiting factor for steelhead when water temperature is outside the range of tolerance.

13. Ecological Succession
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Ecological Succession
Ecosystems are constantly changing.
Forest fires can be good and even necessary for the forest community.
Forest fires return nutrients to the soil.
Some ecosystems depend on fires to get rid of debris.
A forest fire might change the habitat so drastically that some species no longer can survive, but other species might thrive.

14. Ecological Succession
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Ecological Succession
The change in an ecosystem that happens when one community replaces another as a result of changing abiotic and biotic factors is ecological succession.
There are two types of ecological succession—primary succession and secondary succession.

15. Primary succession usually occurs very slowly at first.
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
On a solidified lava flow or exposed rocks on a cliff, no soil is present.
The establishment of a community in an area of exposed rock that does not have any topsoil is primary succession.
Primary succession usually occurs very slowly at first.

16. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology

17. As the organisms die, additional soil is created.
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
As pioneer organisms die, their decaying organic materials, along with bits of sediment from the rocks, make up the first stage of soil development.
At this point, small weedy plants, including ferns and other organisms such as fungi and insects, become established.
As the organisms die, additional soil is created.

18. Eventually enough soil is present so that shrubs and trees can grow.
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Seeds, brought in by animals, water, or wind, begin to grow in the newly formed soil.
Eventually enough soil is present so that shrubs and trees can grow.
The stable, mature community that results when there is little change in the composition of species is a climax community.
Scientists today realize that disturbances, such as climate change, are ongoing in communities, thus a true climax community is unlikely to occur.

19. Chapter 3
Communities, Biomes, and Ecosystems

20. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Disturbances such as fire, flood, or a windstorm can disrupt a community.
After a disturbance, new species of plants and animals might occupy the habitat.
Overtime, there is a natural tendency for the species belonging to the mature community to return

21. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
The orderly and predictable change that takes place after a community of organisms has been removed but the soil has remained intact is secondary succession.
Pioneer species – mainly plants that begin to grow in the disturbed area – are the first species to start secondary succession.

22. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology

23. Chapter Resource Menu Chapter Diagnostic Questions
Communities, Biomes, and Ecosystems
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment
Standardized Test Practice
biologygmh.com
Glencoe Biology Transparencies
Image Bank
Vocabulary
Animation
Click on a hyperlink to view the corresponding feature.

24. Chapter 3
Communities, Biomes, and Ecosystems
Chapter Diagnostic Questions
Mosses and lichens are the first organisms to appear during which ecological stage of an ecosystem?
primary succession
secondary succession
climax community
end succession D C B A
CDQ 1

25. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Formative Questions
What is a group of interacting populations that occupy the same area at the same time?
a biome
a community
an ecosystem
an environment D C B A
FQ 1

26. What occurs in the process of ecological succession?
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Formative Questions
What occurs in the process of ecological succession?
Environmental factors affect the survival of organisms.
One biological community replaces another in the ecosystem.
Organisms adapt to new biotic and abiotic factors.
Pioneer species move in and replace existing species. D C B A
FQ 3

27. Based on the information in the graph, what can be
Chapter 3
Communities, Biomes, and Ecosystems
Chapter Assessment Questions
Based on the
information in the
graph, what can be
inferred about carbon
dioxide in the
atmosphere?
CAQ 2

28. Answer: The measured increase of carbon
Chapter 3
Communities, Biomes, and Ecosystems
Chapter Assessment Questions
Answer: The measured increase of carbon
dioxide (CO2) in the atmosphere
is mainly due to the burning of
fossil fuels. As carbon dioxide
levels have increased, the
average global temperature has
increased.
CAQ 3

29. Use the figure below to infer which abiotic factor
Chapter 3
Communities, Biomes, and Ecosystems
Chapter Assessment Questions
Use the figure below to infer which abiotic factor
might limit the survival of steelhead trout.
Answer: Temperature
CAQ 4

30. What is the most critical limiting factor for a polar bear?
Chapter 3
Communities, Biomes, and Ecosystems
Standardized Test Practice
What is the most critical limiting factor for a polar bear?
precipitation
soil type
sunlight
temperature D C B A
STP 1

31. The mature community in this diagram is a true climax community.
Chapter 3
Communities, Biomes, and Ecosystems
Standardized Test Practice
The mature community in this diagram is a true climax community.
true
false B A
STP 2

32. For which biome was this data collected?
Chapter 3
Communities, Biomes, and Ecosystems
Standardized Test Practice
For which biome was this data collected?
Average precipitation: 38–100 cm per year
Temperature range: 10°C–40°C
Abiotic factors: summers are very hot and dry;
winters are cool and wet
desert
boreal forest
temperate woodland
tropical seasonal forest D C B A
STP 3

33. What type of community is likely to exist near the top of a mountain?
Chapter 3
Communities, Biomes, and Ecosystems
Standardized Test Practice
What type of community is likely to exist near the top of a mountain?
tundra
arctic desert
coniferous forest
temperate grassland D C B A
STP 4

34. Section 1 Vocabulary community limiting factor tolerance
Chapter 3
Communities, Biomes, and Ecosystems
Vocabulary
Section 1
community
limiting factor
tolerance
ecological succession
primary succession
climax community
secondary succession