Populations and the
Environment
Chapter 5, 6.2 and 6.3
5.1 How Populations Grow
Population Density
Population density is a
measurement of the
number of individuals
living in a ...


Population dispersion
refers to how a population
is spread in an area.
Clumped
dispersion

Clumped

Uniform
dispersion
...
Population Growth




The size of a population is
always changing.
Four factors affect the size
of a population.



...


Population growth is based on
available resources.



Exponential growth is a rapid
population increase due to an
abun...
However,


Most populations are regulated by predators,
disease, and the availability of resources.




Because of this...




Logistic growth occurs when a population is
facing limited resources.
Carrying capacity is the maximum number of
ind...
5.2 Limits to Growth



Limiting factors – control the growth of a
population



Density-dependent factors
The rate at w...
Example: Limiting Growth


Density-independent limiting factors limit a
population’s growth regardless of the size and
density.





Hurricane...
1.During which time period is birth rate higher than death rate?
2.During which time period are birth rate and death rate ...
5.3 Human Population Growth


For most of human existence, the
population grew slowly because life was
harsh.


Food was...


Improved nutrition, sanitation, medicine, and
healthcare, dramatically reduced death rates.


birthrates in most parts...
6.2 Using Resources Wisely


How do we obtain what we need from local and
global environments without destroying those
en...
Soil Resources


Healthy soil supports both agriculture and
forestry.





Topsoil – rich in organic matter and nutrie...
Desertification Risk
Soil Use and Sustainablility





Leaving stems and roots of the previous
year’s crops
Crop rotation
Select Harvesting
Freshwater Resources




drinking water, industry, transportation, energy,
and waste disposal.
Some farmland relies heav...
Water Pollution
Many serious environmental problems
occur in our own backyard.
 Agriculture introduces large amounts of
c...
Water Quality and Sustainability




Protecting the water cycle
Clean up pollution
Conserve water
Atmospheric Resources


Air quality has a direct impact on health.




Pollution

Global temperature
Coal-burning power plants send smoke,
containing sulfur, into the atmosphere through
smokestacks.


Scientists now know t...
Decrease in the amount of ozone (O3) in the
atmosphere allows more UV radiation to reach
the earth’s surface.


This can ...
Hole in the ozone layer

Rubin, Ken. “Ask an Earth Scientist.”
Hawaii.Oct 2008. Web. 8 No
The earths average global temperature has been
steadily increasing for more than a century
(Global Warming)


Caused by t...


Earth’s resources must be used responsibly.






Careless use of resources makes them unavailable to
future generat...
Worldwide Ecological Footprints
Determine your ecological
footprint


Go to www.footprintnetwork.org/calculator to
determine how many planet Earths it wo...
6.3 Biodiversity


Biodiversity is one of Earth’s greatest natural
resources. When biodiversity is lost, significant
valu...
The loss of biodiversity has long-term effects.







loss of medical and technological advances
extinction of specie...


Habitat Fragmentation
Hunting and Demand for
Products


Introduced Species


Introduced species can disrupt stable relationships
in an ecosystem.

Burmese python in the Flori...
Conservation




Conservation methods can help protect and
restore ecosystems.
Sustainable development meets needs witho...


Sustainable practices







Timber industry
Fisheries

The Endangered Species Act
Environmental Protection Agency...
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Chapter 5 notes

  1. 1. Populations and the Environment Chapter 5, 6.2 and 6.3
  2. 2. 5.1 How Populations Grow Population Density Population density is a measurement of the number of individuals living in a defined space. Scientists can calculate population density.
  3. 3.  Population dispersion refers to how a population is spread in an area. Clumped dispersion Clumped Uniform dispersion Random Uniform Random dispersion
  4. 4. Population Growth   The size of a population is always changing. Four factors affect the size of a population.     Immigration Births rate Emigration Death rate
  5. 5.  Population growth is based on available resources.  Exponential growth is a rapid population increase due to an abundance of resources.
  6. 6. However,  Most populations are regulated by predators, disease, and the availability of resources.   Because of this population will not exceed the environmental carrying capacity As a population grows, limited resources become depleted and the growth of the population slows.
  7. 7.   Logistic growth occurs when a population is facing limited resources. Carrying capacity is the maximum number of individuals of a particular species that a particular environment can support.
  8. 8. 5.2 Limits to Growth  Limiting factors – control the growth of a population  Density-dependent factors The rate at which they become depleted depends upon the population density of the population that uses them.  Competition  Predation  Disease  Overcrowding  Herbivory 
  9. 9. Example: Limiting Growth
  10. 10.  Density-independent limiting factors limit a population’s growth regardless of the size and density.     Hurricanes Drought Floods Wildfires
  11. 11. 1.During which time period is birth rate higher than death rate? 2.During which time period are birth rate and death rate equal? 3.During which time period is death rate higher than birth rate?
  12. 12. 5.3 Human Population Growth  For most of human existence, the population grew slowly because life was harsh.  Food was hard to find. Predators and diseases were common and life-threatening.  These limiting factors kept human death rates very high.
  13. 13.  Improved nutrition, sanitation, medicine, and healthcare, dramatically reduced death rates.  birthrates in most parts of the world remained high.  The combination of lower death rates and high birthrates led to exponential growth.
  14. 14. 6.2 Using Resources Wisely  How do we obtain what we need from local and global environments without destroying those environments? Environmental Resources we affect:  Soil  Freshwater  Air
  15. 15. Soil Resources  Healthy soil supports both agriculture and forestry.    Topsoil – rich in organic matter and nutrients Loss of fertile soil can have dire consequences. Erosion – removal of soil by water or wind Desertification  Deforestation 
  16. 16. Desertification Risk
  17. 17. Soil Use and Sustainablility    Leaving stems and roots of the previous year’s crops Crop rotation Select Harvesting
  18. 18. Freshwater Resources   drinking water, industry, transportation, energy, and waste disposal. Some farmland relies heavily on irrigation
  19. 19. Water Pollution Many serious environmental problems occur in our own backyard.  Agriculture introduces large amounts of chemicals into the global ecosystem.  Including: pesticides, herbicides, and fertilizers  Many chemicals, such as DDT, have been banned in the US, but the effects of their use still circulate. Causes biological magnification 
  20. 20. Water Quality and Sustainability    Protecting the water cycle Clean up pollution Conserve water
  21. 21. Atmospheric Resources  Air quality has a direct impact on health.   Pollution Global temperature
  22. 22. Coal-burning power plants send smoke, containing sulfur, into the atmosphere through smokestacks.  Scientists now know that the sulfur can combine with water vapor to produce sulfuric acid, which will fall back to earth as acid rain. Acid rain causes forest damage, and dead lakes  Robl, Ernest H. Acid Rain Damage. Photograph 1990. Web. 21 Oct 2010.
  23. 23. Decrease in the amount of ozone (O3) in the atmosphere allows more UV radiation to reach the earth’s surface.  This can cause an increase in diseases related to UV exposure such as cancer and cataracts. The major cause is chlorofluorocarbons (CFCs) commonly used in refrigerators, air conditioners, and in aerosols. As a result CFCs have been banned in the US. 
  24. 24. Hole in the ozone layer Rubin, Ken. “Ask an Earth Scientist.” Hawaii.Oct 2008. Web. 8 No
  25. 25. The earths average global temperature has been steadily increasing for more than a century (Global Warming)  Caused by the greenhouse effect, in which greenhouse gasses trap the suns energy within the atmosphere. 
  26. 26.  Earth’s resources must be used responsibly.    Careless use of resources makes them unavailable to future generations. An ecological footprint is the amount of land needed to support a person. The land must produce and maintain enough     food and water shelter energy Room for waste
  27. 27. Worldwide Ecological Footprints
  28. 28. Determine your ecological footprint  Go to www.footprintnetwork.org/calculator to determine how many planet Earths it would take to support everyone if they lived like you.
  29. 29. 6.3 Biodiversity  Biodiversity is one of Earth’s greatest natural resources. When biodiversity is lost, significant value to the biosphere and to humanity may be lost along with it.
  30. 30. The loss of biodiversity has long-term effects.     loss of medical and technological advances extinction of species loss of ecosystem stability
  31. 31.  Habitat Fragmentation
  32. 32. Hunting and Demand for Products
  33. 33.  Introduced Species  Introduced species can disrupt stable relationships in an ecosystem. Burmese python in the Florida Everglades Kudzu
  34. 34. Conservation   Conservation methods can help protect and restore ecosystems. Sustainable development meets needs without hurting future generations.   resources meet current needs resources will still be available for future use
  35. 35.  Sustainable practices      Timber industry Fisheries The Endangered Species Act Environmental Protection Agency (EPA) National Park Service

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