Chapter%205%20

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Chapter 5 Populations Chapter 6 Humans In the
Biosphere
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I. Characteristics of Populations
A. Geographic distribution - (range) area
inhabited by a population
B. Population density-number of individuals per
unit area ex 200 people/ km2
C. Growth rate- increase or decrease of number of
individuals in a population over time.
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II. 3 Factors that Affect Population Size
A. number of births
B. number of deaths
C. number of individuals entering (into-
immigration) or leaving (exiting- emigration) a
population
D. Population grows when birthrate is greater
than deathrate.
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III. Exponential growth - when the individuals in
a population reproduce at a constant
rate.

1. Population becomes larger and larger until it
   approaches an infinitely large size.

B. Under ideal conditions with unlimited
resources, a population would grow
exponentially (J-shaped curve)
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IV. Logistic Growth - when growth slows or stops
following a period of exponential
growth (S-shaped curve)
A. carrying capacity (K)-
largest of individuals of a population that an
environment can support
B. Growth levels off, so the average growth rate
is zero.
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V. Limiting factor -factor that causes population
growth to decrease
A. Density-dependent limiting factor - limiting
factor that depends on pop. size
1. Ex competition, predation, parasitism,
disease, crowding
2. Has greatest influence when pop. is large
dense does not affect small, scattered
pop. as greatly
3. Competition- when pops. become crowded, they
compete for food, water, space, sunlight,
other resources
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4. Predation- regulation of a pop. by predation
is a predator-prey relationship
Wolf and Moose Populations on Isle Royale
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B. Density-independent limiting factors -affect
all pops in similar ways, regardless of the pop.
size.
1. Ex. weather, drought/floods, fire, human
activity (clear-cutting, damming rivers,
development)
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5-3
VI. Human Populations

1. Began growing more rapidly due to advances in
   agriculture and industry.

B. Death rates- reduced due to improved
sanitation, medicine, healthcare, while
birthrates remained high.
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5-3
Human Population Growth
C. Demography-study of human population growth
1. past century- pop. growth in US, Japan, Europe
has slowed
2. Demographic Transition, a huge change in
birth and death rates.
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5-3
D. 3 stages of Dem. Trans
1. Stage 1- high birthrate high death rate
2. Stage 2- birthrate high death rate drops
3. Stage 3-birthrate drops pop growth slows
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5-3
U.S. Population
E. Age-structure diagram shows the pop. of a
country broken down by gender and age group can
predict future growth of pop.
1. US- nearly equal no. of people in each age
group
2. predicts a slow but steady growth rate for the
near future
Percentage of Population
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Rwandan Population
5-3
3. Rwanda- many more children/ teenagers, than
adults.
4. diagram predicts pop. will double in about 30
years
Percentage of Population
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5-3
F. To predict human pop. growth, demographers
must consider age structure and disease.
1. If growth does not slow ?damage to the
environment and global economy.
2. Science, technology, changes in society may
limit the negative impact of population growth.
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6-1
I. Human activities affect the biosphere.
A. Hunting-gathering- isolated parts of the world
B. Agriculture -Irrigation, fertilizers,
pesticides
C. Industrial Revolution to Present
1. Increased pollution of air, water, soil by
fossil fuels
2. Increased human waste and increased
development places stress on native plants/
animals consumes farmland
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• D. Pollution ? contamination of soil, water, or
  air
• 1. has increased as countries become
  industrialized
• 2. Pollutant - harmful material that can
  enter the biosphere through the land, air, or
  water
• 3. Air Pollution ?caused by burning of
  fossil fuels that release pollutants that cause
  smog
• a. example driving cars, flying planes, heating
  homes, factories
• b. example of air pollutants ? dust, smoke, ash,
  CO,
• sulfur oxides
• Strict emissions and clean-air regulations have
  improved air quality

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c. Causes ?Acid rain- sulfuric acid/nitric acid
from the burning of fossil fuels
mix with water vapor forming low pH rain (car
exhaust nitric acid coal-burning factories
sulfuric acid)
Acid rain damages plants, kills aquatic
organisms, erodes buildings and monuments,
depletes soil of nutrients
Condensation
Emissions to Atmosphere Nitrogen oxides Sulfur
dioxide
Chemical Transformation Nitric acid Sulfuric acid
Dry Fallout Particulates Gases
Precipitation Acid rain, fog, snow, and mist
Power generation
Ore smelting
Transportation
Industry
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d. Burning fossil fuels releases Carbon Dioxide
into the atmosphere. - Excess CO2 can
contribute to the greenhouse effect ? thought to
be the cause of global warming
e. Global warming- cycle or human activity ?- CO2
levels have increased over past 200
yrs-intensifies greenhouse effect
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Page 87
f. Greenhouse Effect
Some heat escapes into space

• Atmospheric gases that trap the heat energy of
  sunlight and maintain Earth's temperature range
  include
• carbon dioxide
• methane
• water vapor

Greenhouse gases trap some heat
Atmosphere
Earths Surface
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g. Monitor ozone layer and global climate system
1. Ozone layer- O3-protects Earth from UV
radiation? can cause cancer, eye disease,
tissue damage in plants
2. CFCs (Chlorofluorocarbons) destroys ozone
layer found in aerosols and coolants
have been reduced
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4. Water Pollution ? caused by contaminants from
sewers, industries, farms, and homes that
enter lakes, rivers, groundwater and oceans
Sewage, chemical waste, fertilizer, and
dirty wash water enter the water systems
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Terracing
Contour Plowing
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II. Renewable and nonrenewable resources

• Renewable resources (rnr)- can regenerate (if
  living) or be recycled (if part of biogeochemical
  cycles)
• Ex trees, water

B. Nonrenewable resources- cannot be
replenished by natural processes, are in limited
amounts, once they are gone they are gone!!
Ex. Fossil fuels such as coal and oil, gold,
silver, copper
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C. Renewable or nonrenewable?

• Depends on if the loss is large enough to change
  an
• ecosystem forever ex coral reefs

2. ex single treerenewable resource, but an
entire pop. of trees may change the entire
ecosystem
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III. Biodiversity-sum total of the genetically
based variety of all organisms in the biosphere
Three types of diversity in ecosystems
A. Ecosystem diversity-variety of habitats,
communities, and ecological processes in the
living world.
B. Species diversity is the of different
species in biosphere increases moving towards
equator.
C. Genetic diversity is the sum total of all the
different forms of genetic information carried by
all organisms living on Earth today.
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IV. Importance of Biodiversity
A. Plants and some animals produce compounds
that are beneficial
B. food, industry, medical- painkillers,
antibiotics, antidepressants cancer/heart
drugs/ high blood pressure ex rosy
periwinkle and digitalis
Rosy periwinkle ?
digitalis? Foxglove
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V. Threats to Biodiversity
1. Loss of habitat- degradation (damage by
pollution) fragmentation (split into pieces)
2. Hunting- food, fur,pets (birds), poaching
3. Introduced species- may become invasive
species (lack predators from homeland)
wipe-out native pops. Ex zebra mussels,leafy
spurge, goats
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Leafy spurge
Zebra mussel
Zebra mussels can attach to native mussels,
killing them. Zebra mussels filter plankton from
the surrounding water. This filtering can
increase water clarity, which might cause more
aquatic vegetation to grow at deeper depths and
more dense stands. If a lake has high numbers of
mussels over large areas, this filter feeding
could impact the food chain, reducing food for
larval fish.
This plant is an invasive, deep-rooted perennial
herb that is native to Eurasia plant spreads
through explosive seed release and vigorous
lateral root growth, forming large, patches that
can dominate rangeland, pastures, prairies and
other areas in the Great Plains region of North
America, killing native plant species.
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4. Pollution ? DDT-softened shells of birds
eggs - osprey, brown pelican, eagle
population threatened
a. Rachel Carson- 1962 Silent Spring- book
about dangers of biological magnification
b. Biological magnification
concentration of harmful substances
increase at higher trophic levels DDT banned
US- 1970s
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VI. Conservation- management of resources,
habitats, and wildlife
1. US Endangered Species Act-1973-illegal to harm
endangered or threatened species
2. Expand National Parks or green space in
cities
3. Habitat corridors-strips of land that allow
migration
4. Reintroduction programs- breed animals, then
release back into wild
5. Identify global hot spots-(organisms are in
danger of extinction due to human activity) work
on protecting those habitats often endemic
species (found no where else in the world!!)
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5-1

• Population density is the number of individuals
• A. that are born each year.
• B. per unit area.
• C. that immigrate.
• D. that emigrate.

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5-1

• When the birthrate of a population exceeds its
  death rate, the population
• A. decreases.
• B. increases.
• C. stays the same.
• D. increases then decreases.

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5-1

• An S-shaped curve on a graph of population growth
  is characteristic of
• A. exponential growth.
• B. logistic growth.
• C. carrying capacity.
• D. delayed growth.

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5-1

• Exponential growth in a population slows down or
  stops as
• A. resources become limited.
• B. rate of immigration increases.
• C. rate of emigration decreases.
• D. birth rate increases.

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5-1

• Exponential growth rate means that each new
  generation of a population
• A. adds the same number of new individuals as the
  previous generation did.
• B. increases at the same rate as the previous
  generation
• C. is the same size as the generation before.
• D. increases by a varying amount.

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5-2

• A limiting factor that affects all populations in
  similar ways regardless of their size might be
• A. drought.
• B. disease.
• C. predation.
• D. crowding.

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5-2

• Which of the following would be a limiting factor
  directly affecting the panda population of China?
• A. programs that educate people about endangered
  species
• B. capture of some pandas for placement in zoos
• C. laws protecting habitat destruction
• D. a disease that kills bamboo plants

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5-2

• Density-dependent factors operate most strongly
  when a population is
• A. large and dense.
• B. large but sparse.
• C. small and sparse.
• D. small, but growing.

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5-2

• Within a limited area, if the population of a
  predator increases, the population of its prey is
  likely to
• A. increase.
• B. decrease.
• C. remain about the same.
• D. become extinct.

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5-2

• Which of the following is a density-independent
  factor affecting populations?
• A. predation
• B. disease
• C. a destructive hurricane
• D. parasites

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5-3

• The size of the human population began to
  increase exponentially after the
• A. bubonic plague.
• B. development of plowing and irrigation.
• C. Industrial Revolution.
• D. development of the first cities.

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5-3

• Which of the following is NOT a potential
  limiting factor of human population growth?
• A. famine
• B. medicine
• C. war
• D. disease

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5-3

• After the demographic transition is complete, a
  population
• A. grows rapidly.
• B. grows slowly.
• C. begins a period of rapid decline.
• D. stays about the same size as time passes.

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5-3

• An age-structure diagram shows a breakdown of a
  population by
• A. location and age group.
• B. age group and gender.
• C. birthrate and death rate.
• D. age group and emigration rate.

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5-3

• Since the mid-1960s, the average annual growth
  rate of the human population has
• A. remained about the same.
• B. failed to show a consistent pattern.
• C. increased.
• D. decreased.