1. Chapter 3 Communities, Biomes, and Ecosystems

2. 3.1 Community Ecology
A biological community is a group of interacting populations that occupy the same area at the same time

3. Communities Organisms rely on one another to survive
Abiotic factors affect communities and the organisms in them
Organisms adapt to the conditions they live in
Cactus retaining water in the harsh climate of a desert
Depending on which factors are present, organisms can survive in one ecosystem, but not others

4. Limiting Factors
Any abiotic or biotic factor that limits the numbers, reproduction, or distribution of organisms
Includes sunlight, temperature, climate, water, nutrients, fire, soil chemistry, space, and other living things
How would temperature be a limiting factor for polar bears?

5. Range of Tolerance
The upper and lower limits that define the conditions in which an organism can survive
Ideal water temp for steelhead trout is between 9°C and 25°C
The ability of an organism to survive in certain abiotic or biotic factors is called tolerance

6. Ecological Succession
The living and nonliving parts of an ecosystem change over a period of time
Forest fire
The changes that take place in a community as it gets older is called SUCCESSION

7. Succession
Succession happens SLOWLY! So it can be hard to see happening.

8. Primary Succession
occurs at an area of NEWLY EXPOSED rock (no soil) that has never been occupied by any living things (biotic factors)

9. Pioneer Species Lichens – a combination of fungus and algae
Lichens begin to grow on the bare rock
Since they are the first organisms to appear, they are called pioneer species
Pioneer species help to create soil by secreting acids that break down the rock

10. Climax Communities
A mature community eventually develops from bare rock
Climax Community – the stable, mature community that results when there is little change in the composition of species
It is the final stage of succession in a community, however, because of ecological disturbances, climax communities are unlikely to occur

11. Secondary Succession
Occurs when a community has been removed due to fire, flood, windstorm, etc.
New species may begin to occupy the habitat
Over time, the species belonging to the mature community may return

12. Secondary Succession
The orderly and predictable change that takes place after a community of organisms has been removed, but the soil has remained intact.

13. Chapter 4 Population Ecology

14. 4.1 Population Dynamics
Populations of species are described by density, spatial distribution, and growth rate
Population Density – the number of organisms per unit area

15. Spatial Distribution
Dispersion – the pattern of spacing of a population within an area
Uniform, clumped groups, or random
One primary factor in the pattern is availability of resources

16. Population Range
No population, not even humans, occupies all habitats in the biosphere
A species may not be able to expand it population range because it cannot survive the abiotic or biotic conditions found in the expanded range
Abiotic conditions – temperature, rainfall, sunlight, humidity level
Biotic conditions – predators, competitors, parasites

17. Population Limiting Factors
Factors that keep a population from continuing to increase
Density-independent
Density-dependent

18. Population Limiting Factors
Density-Independent
Density-Dependent
any factor that does not depend on the number of members in the population
Usually abiotic
natural events like the weather (drought, flooding, etc.)
human interference
any factor that depends on the number of members in a population
Usually biotic
Competition – density is high, resources are low
Disease – density is high
Parasites – density is high

19. Population Growth Rate
Explains how fast a given population grows
Emigration – number of individuals moving away from a population
Immigration – number of individuals moving into a population
Most populations remain the same size from year to year

20. Population Growth Rate
A population stops increasing when the number of births is less than the number of deaths, or when emigration (moving out) exceeds immigration (moving in)

21. Carrying Capacity
Maximum number of species an environment can support for the long term
Limited by energy, water, oxygen,

22. Reproductive Patterns
Species of organisms vary in the number of births per reproduction cycle, the age that reproduction begins, and in the life span of the organisms
Plants and animals are placed into groups based on their reproductive factors
R-strategists
K-strategists

23. Reproductive Patterns
K-Strategists
R-Strategists
Rate strategy
Live in an environment that fluctuate
Usually small organisms (mice, fruit fly)
Short life spans, produce many offspring
Usually controlled by density-independent factors
STRATEGY: produce as many offspring as possible in a short period of time
Carrying-capacity
Live in environments that are predictable
Larger organisms (elephant)
Long life span, produce few offspring
Controlled by density-dependent factors
STRATEGY: produce fewer offspring that have a better chance of living

24. 4.2 Human Population
Demography: the study of human population size, density, distribution, movement, and birth and death rates

25. Advances
For years, environmental conditions kept the human population size below carrying capacity
Humans have altered the environment to change the carrying capacity

26. Advances Agricultural advances Domestication of animals Technology
Medicine
Improvements in shelter

27. Human Population Growth Rate
Although the population is still growing, the growth rate has slowed

28. Trends in Human Population Growth
Can be altered by war and disease
Demographic Transition – change in population from high birth/death rates to low birth/death rates

29. Zero Population Growth
(ZPG) when births plus immigration = deaths plus emigration
The population has stopped growing because births and deaths occur at the same rate

30. Human Carrying Capacity
Scientists are concerned about the population reaching or exceeding the carrying capacity
Resources from the biosphere used by each person must also be limited

31. Chapter 4
Population Ecology
Chapter Diagnostic Questions
What term is used to describe the number of individuals moving into a population?
emigration
imitation
immigration
migration A B C D
CDQ 1

32. What is population density?
Chapter 4
Population Ecology
Chapter Diagnostic Questions
What is population density?
pattern of spacing of a population in an area
number of organisms in an area
characteristics of a population
manner in which a population grows A B C D
CDQ 2

33. When does zero population growth occur?
Chapter 4
Population Ecology
Chapter Diagnostic Questions
When does zero population growth occur?
when birth rate equals death rate
when death rate exceeds birth rate
when birth rate exceeds death rate
when there are zero births A B C D
CDQ 3

34. Which is a density-dependent factor?
Chapter 4
Population Ecology
4.1 Formative Questions
Which is a density-dependent factor?
disease
fire
flooding
weather A B C D
FQ 1

35. Which is a density-independent factor?
Chapter 4
Population Ecology
4.1 Formative Questions
Which is a density-independent factor?
competition
extreme cold
parasites
predation A B C D
FQ 2

36. Which factor can limit the carrying capacity of a population?
Chapter 4
Population Ecology
4.1 Formative Questions
Which factor can limit the carrying capacity of a population?
emigration
predation
available nutrients
extreme temperatures A B C D
FQ 3

37. Chapter 4
Population Ecology
4.2 Formative Questions
The study of the size, density, distribution, and movement of the human population is _______.
bioinformatics
demography
ecology
ethnography A B C D
FQ 4

38. decreased agriculture famine and wars setbacks in medicine
Chapter 4
Population Ecology
4.2 Formative Questions
Which is a primary reason for the decline in the percent growth of the human population after 1962?
decreased agriculture
famine and wars
setbacks in medicine
voluntary population
control A B C D
FQ 5

39. Chapter 4
Population Ecology
4.2 Formative Questions
What will happen to the human population when the birthrate equals the death rate?
CDC
HPG
PGR
ZPG A B D C
FQ 6

40. Which type of population growth model does this graph represent?
Chapter 4
Population Ecology
Chapter Assessment Questions
Which type of population growth model does this graph represent?
exponential
spatial
genetic
logistic A B C D
CAQ 1

41. Chapter 4
Population Ecology
Chapter Assessment Questions
Based on the information in the graph, infer which statement accurately represents the information provided.
India has very little land for farming.
Germany is smaller per acre than the United States.
More land is used to support an individual in the United States.
A person in Indonesia requires more land than a person in Brazil. A B C D
CAQ 2

42. Use the graph to explain the growth of the mice population.
Chapter 4
Population Ecology
Chapter Assessment Questions
Use the graph to explain the growth of the
mice population.
CAQ 3

43. Answer: If two adult mice breed and produce a litter
Chapter 4
Population Ecology
Chapter Assessment Questions
Answer: If two adult mice breed and produce a litter
and their offspring survive to breed, then the
population grows slowly at first. This slow
growth is defined as the lag phase. The rate
of population growth begins to increase
rapidly because the total number of
organisms that are able to reproduce has
increased. Exponential growth occurs when
the growth rate is proportional to the size of
the population. All populations grow
exponentially until some limiting factor slows
the population’s growth.
CAQ 4

44. Chapter 4
Population Ecology
Standardized Test Practice
An ecologist estimates a population density of 2.3 lemmings per square meter of tundra. What would be the approximate number of lemmings over 1000 square meters of tundra?
0.23 23
230
2300 A B C D
STP 1

45. Chapter 4
Population Ecology
Standardized Test Practice
The ecologist finds that over a 1000m2 plot of tundra, lemmings tend to concentrate in clumps in drier areas. What is the term for this pattern of spacing?
density
dispersion
logistic spacing
spatial distribution A B C D
STP 2

46. It is density-dependent. It is limited by biotic factors.
Chapter 4
Population Ecology
Standardized Test Practice
Brine shrimp are able to survive only in certain lakes that have a very high salt concentration. Which is the correct population characteristic of brine shrimp?
It is density-dependent.
It is limited by biotic factors.
It has a limited spatial distribution.
It is randomly dispersed in the environment. A B C D
STP 3

47. Standardized Test Practice
Chapter 4
Population Ecology
Standardized Test Practice
Why does the population growth level off at 10,000?
Biotic factors have made survival difficult.
The population has reached its carrying capacity.
Density-independent factors have slowed the growth of the population.
Immigration into the population has reached the maximum limit. A B C D
STP 4

48. Which organism is the best example of a k-strategist?
Chapter 4
Population Ecology
Standardized Test Practice
Which organism is the best example of a k-strategist?
wolf
grasshopper
rabbit
whale A B C D
STP 5

49. Glencoe Biology Transparencies
Chapter 4
Population Ecology
Glencoe Biology Transparencies

50. Chapter 4
Population Ecology
Image Bank

51. Section 1 Vocabulary population density dispersion
Chapter 4
Population Ecology
Vocabulary
Section 1
population density
dispersion
density-independent factor
density-dependent factor
population growth rate
emigration
immigration
carrying capacity

52. Section 2 Vocabulary demography demographic transition
Chapter 4
Population Ecology
Vocabulary
Section 2
demography
demographic transition
zero population growth (ZPG)
age structure

53. Visualizing Population Characteristics
Chapter 4
Population Ecology
Animation
Visualizing Population Characteristics
Characteristics of Population Growth

54. Chapter 4
Population Ecology

55. Chapter 4
Population Ecology