Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology A biological community is a...
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Transcript of Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology A biological community is a...
Chapter 3 Communities, Biomes, and Ecosystems
3.1 Community Ecology A biological
community is a group of interacting populations that occupy the same area at the same time
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
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?
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
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
Succession Succession happens SLOWLY! So it can
be hard to see happening.
Primary Succession
occurs at an area of NEWLY EXPOSED rock (no soil) that has never been occupied by any living things (biotic factors)
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
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
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
Secondary Succession The orderly and predictable change that takes
place after a community of organisms has been removed, but the soil has remained intact.
Chapter 4Population Ecology
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
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
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
Population Limiting Factors Factors that keep a population from
continuing to increase Density-independent Density-dependent
Population Limiting Factors
Density-Independent
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
Density-Dependent
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
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
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)
Carrying Capacity Maximum number of species an
environment can support for the long term
Limited by energy, water, oxygen,
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
Reproductive PatternsR-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
K-Strategists 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
4.2 Human Population Demography: the study of human
population size, density, distribution, movement, and birth and death rates
Advances For years, environmental conditions kept
the human population size below carrying capacity
Humans have altered the environment to change the carrying capacity
Advances Agricultural
advances Domestication of
animals Technology Medicine Improvements in
shelter
Human Population Growth Rate Although the
population is still growing, the growth rate has slowed
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
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
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
1. A2. B3. C4. D
0% 0%0%0%
A. emigration
B. imitation
C. immigration
D. migration
Population EcologyChapter 4
Chapter Diagnostic Questions
What term is used to describe the number ofindividuals moving into a population?
1. A2. B3. C4. D
0% 0%0%0%
Population EcologyChapter 4
Chapter Diagnostic Questions
B. number of organisms in an area
C. characteristics of a population
D. manner in which a population grows
A. pattern of spacing of a population in an area
What is population density?
1. A2. B3. C4. D
0% 0%0%0%
Population EcologyChapter 4
Chapter Diagnostic Questions
A. when birth rate equals death rate
B. when death rate exceeds birth rate
C. when birth rate exceeds death rate
D. when there are zero births
When does zero population growth occur?
1. A2. B3. C4. D
0% 0%0%0%
Population EcologyChapter 4
A. disease
B. fire
C. flooding
D. weather
4.1 Formative Questions
Which is a density-dependent factor?
1. A2. B3. C4. D
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Population EcologyChapter 4
A. competition
B. extreme cold
C. parasites
D. predation
4.1 Formative Questions
Which is a density-independent factor?
1. A2. B3. C4. D
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Population EcologyChapter 4
A. emigration
B. predation
C. available nutrients
D. extreme temperatures
4.1 Formative Questions
Which factor can limit the carrying capacity of a population?
1. A2. B3. C4. D
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Population EcologyChapter 4
4.2 Formative Questions
A. bioinformatics
B. demography
C. ecology
D. ethnography
The study of the size, density, distribution,
and movement of the human population is _______.
1. A2. B3. C4. D0% 0%0%0%
Population EcologyChapter 4
4.2 Formative Questions
A. decreased agriculture
B. famine and wars
C. setbacks in medicine
D. voluntary populationcontrol
Which is a primary reason for the decline in the percent growth of the human population after 1962?
1. A2. B3. C4. D
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Population EcologyChapter 4
4.2 Formative Questions
A. CDC
B. HPG
C. PGR
D. ZPG
What will happen to the human population
when the birthrate equals the death rate?
1. A2. B3. C4. D0% 0%0%0%
Population EcologyChapter 4
A. exponential
B. spatial
C. genetic
D. logistic
Chapter Assessment Questions
Which type of population growth model does this graph represent?
1. A2. B3. C4. D0% 0%0%0%
Population EcologyChapter 4
A. India has very little land for
farming.
B. Germany is smaller per acre than
the United States.
C. More land is used to support an
individual in the United States.
D. A person in Indonesia requires
more
land than a person in Brazil.
Chapter Assessment Questions
Based on the information in the graph, infer which statement accurately represents the information provided.
Use the graph to explain the growth of the
mice population.
Population EcologyChapter 4
Chapter Assessment Questions
Answer: If two adult mice breed and produce a litterand 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.
Population EcologyChapter 4
Chapter Assessment Questions
1. A2. B3. C4. D
0% 0%0%0%
Population EcologyChapter 4
A. 0.23
B. 23
C. 230
D. 2300
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?
1. A2. B3. C4. D
0% 0%0%0%
Population EcologyChapter 4
Standardized Test Practice
A. density
B. dispersion
C. logistic spacing
D. spatial distribution
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?
1. A2. B3. C4. D
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Population EcologyChapter 4
Standardized Test Practice
A. It is density-dependent.B. It is limited by biotic
factors.C. It has a limited spatial
distribution.D. It is randomly dispersed
in the environment.
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?
1. A2. B3. C4. D0% 0%0%0%
Population EcologyChapter 4
Standardized Test Practice
Why does the population growth level off at 10,000?
A. Biotic factors have made survival difficult.
B. The population has reached its carrying capacity.
C. Density-independent factors have slowed the growth of the population.
D. Immigration into the population has reached the maximum limit.
1. A2. B3. C4. D
0% 0%0%0%
Population EcologyChapter 4
Standardized Test Practice
Which organism is the best example of a k-strategist?
A. wolf
B. grasshopper
C. rabbit
D. whale
Population Ecology
Glencoe Biology Transparencies
Chapter 4
Population Ecology
Image Bank
Chapter 4
population density
dispersion
density-independent
factor
density-dependent
factor
population growth
rate
emigration
immigration
carrying capacity
Population Ecology
Vocabulary
Section 1
Chapter 4
demography
demographic transition
zero population growth (ZPG)
age structure
Population Ecology
Vocabulary
Section 2
Chapter 4
Population EcologyChapter 4
Visualizing Population Characteristi
cs
Characteristics of Population Growt
h
Animation
Population EcologyChapter 4
Population EcologyChapter 4