Human Ecology• The relationship between humans and their  environment
Characteristics of Populations
•   Location•   Density•   Growth Rate• What causes a population’s size to change?    –   Number of births    –   Number o...
Population Growth                    • Under ideal conditions                      populations grow                      e...
Population Growth                    • In the natural world,                      populations show “logistic              ...
Limiting Factors!!!• Density Independent          • Density Dependent  Limits                         limits  – Limits tha...
What about human populations?                  • World wide human                      population growth =                ...
Biodiversity
Biodiversity               • The variety of                species in an area
high biodiversityMarine                                        coral reef= lots of light                                 b...
high biodiversityTropical rainforest                lots of rain, lots of sunlight, always warm                many plants...
mid biodiversityGrasslands   dry season/wet season, always warm             frequent fires in dry season             many ...
low biodiversityDesert         very dry, hot in day & cold at night         very few plants & only small animals:         ...
low biodiversityTundra         cold year round, dry, permafrost         only lichens & mosses & mostly migrating animals
Why is Biodiversity Important?• Stability• Food source - removing organisms from the food  chain will cause problems for i...
What happens when biodiversity is threatened?• Threatened species   – Population whose #’s are declining rapidly   – sea o...
Humans and the Ecosystem
• Disrupting ecosystems can threaten biodiversity.     • Hunting & gathering     • Agriculture     • Animal domestication ...
What happens?1. Urbanization – movement to cities   – Outcome     • Increased runoff causing flooding & erosion     • Use ...
What happens?2. Deforestation  – Human destruction of    forests  – building of malls,    homes, farming  – Outcome      •...
3. Overfarming  – When plants are harvested soil    becomes less fertile  – Outcome    • Abandoned fields    • Erosion of ...
4. Overgrazing  – Herds of cattle &    sheep overgraze    grasslands  – Outcome     • Land has no cover &      topsoil is ...
5. Misuse of Pesticides  – Contaminate air, water    & soil  – Kill many organisms    that aren’t pests  – “Safe” pesticid...
6. Biomagnification  – Process where chemical becomes highly concentrated in    the bodies of upper level consumers  – How...
7. Invasive species  – Introduction of organisms that    are not native (natural) to an    area      • E.g. Purple loosest...
Pollution You Stink
• Adding anything to the environment or affecting the environment in a way that makes it less fit for living
1. Land Pollution• Tons of solid waste (refuse) are  produced everyday• Sanitary Landfill• Incineration
2. Water Pollution• Organic wastes  – fertilizer runoff, sewage, waste from factories  – Waste acts as food for algae, alg...
Water Pollution• Inorganic chemicals  – Poisonous wastes dumped into waterways    from cities, farms & industry  – Biologi...
Water Pollution• Thermal Pollution.  – Warm water can’t hold as    much oxygen as cool    water. Organisms will    suffoca...
3. Air Pollution• Burning Fossil Fuels  – Burning of coal & gas  – Cars, factories, electrical plants  – Release CO2, sulf...
Air Pollution• Acid Rain  – Occurs when sulfur &    nitrogen combine with water  – Forms in the rain, snow, & sleet  – Low...
Air Pollution• Smog  –   Produced from auto exhaust & industrial processes  –   Results in toxins that can be inhaled  –  ...
Air Pollution• Climate Change  – Change in the climate    (temp, precipitation,    wind) last for an    extended period of...
Air Pollution• Greenhouse effect  Greenhouse effect   – Occurs when sunlight passes     through atmosphere gases       • C...
Air Pollution• Ozone Depletion (not global warming)   – The ozone layer is made of ozone gas (O3) and is found     between...
• Ozone Depletion  – CFCs (chlorofluorocarbons) cause ozone to break down     • Found in aerosols, refrigerators, & air co...
Natural Resources
Restoring the Environment – What can we do?• Nonrenewable natural        • Renewable natural  resource                    ...
Natural Resources• Conserving both renewable & nonrenewable natural  resources is important  – Sustainable use – use natur...
2. Conserving Soil• Soil is renewable, but the process is very slow,  therefore it is important to conserve• Cover crops  ...
Conserving Soil - HOW???•   Crop rotation•   Fertilizer•   Strip cropping•   Terracing•   Contour Farming•   Windbreaks
3. Conserving Forests - WHY and HOW???                        • Sustained-yield tree farming                            – ...
4. Restoring the Environment - Conserving Wildlife • Cities & suburbs destroy natural habitats • Protection    –   Hunting...
Controlling Pests Biologically•   More specific than chemical pesticides•   Fewer adverse environmental effects•   How ?  ...
Controlling Pests Biologically• Crop rotation   – Remove favored food source…• Pheromones   – Lure insect to trap & kill• ...
5. Controlling Pollution•   Emission Controls for cars•   Ban aerosol sprays•   Control Industrial waste    – Gas treated ...
Restoring the Environment• Individual Actions   – People can choose:      • Not to pollute      • Not to burn garbage     ...
Restoring the Environment• Societal Actions   – Cities, States, &     governments can:      • Pass laws against        pol...
Human ecology2012
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  • http://www.fws.gov/Endangered/wildlife.html#Species http://www.endangeredspeciesinternational.org/overview1.html
  • Transcript of "Human ecology2012"

    1. 1. Human Ecology• The relationship between humans and their environment
    2. 2. Characteristics of Populations
    3. 3. • Location• Density• Growth Rate• What causes a population’s size to change? – Number of births – Number of deaths – Number of individuals that move in or out of population
    4. 4. Population Growth • Under ideal conditions populations grow exponentially – As population grows larger, it grows faster
    5. 5. Population Growth • In the natural world, populations show “logistic growth” – Populations growth slows or stops after a period of exponential growth – Population reaches a carrying capacity
    6. 6. Limiting Factors!!!• Density Independent • Density Dependent Limits limits – Limits that affect a – Limits that increase as population regardless of population size population size increases – temperature, storms, – disease, parasites, flood competition, predators
    7. 7. What about human populations? • World wide human population growth = exponential! • Why? – Humans can eliminate competition, increase food production, control disease, etc.
    8. 8. Biodiversity
    9. 9. Biodiversity • The variety of species in an area
    10. 10. high biodiversityMarine coral reef= lots of light benthos= deep ocean intertidal= lots of nutrients
    11. 11. high biodiversityTropical rainforest lots of rain, lots of sunlight, always warm many plants & animals
    12. 12. mid biodiversityGrasslands dry season/wet season, always warm frequent fires in dry season many herbivores
    13. 13. low biodiversityDesert very dry, hot in day & cold at night very few plants & only small animals: reptiles, insects, rodents, birds
    14. 14. low biodiversityTundra cold year round, dry, permafrost only lichens & mosses & mostly migrating animals
    15. 15. Why is Biodiversity Important?• Stability• Food source - removing organisms from the food chain will cause problems for its predator• Pharmaceutical drug development – Taxol – from Pacific Yew tree, breast cancer treatment – Periwinkle – flower used to treat leukemia – Willow bark – natural source for aspirin – Penicillium – mold that makes the antibiotic penicillin• Provides the world with beauty
    16. 16. What happens when biodiversity is threatened?• Threatened species – Population whose #’s are declining rapidly – sea otter, sea turtles• Endangered species – Population with very low numbers – ~ 1214 animals & ~750 plants – manatees, elephants• Extinction – ~ 905 species are extinct
    17. 17. Humans and the Ecosystem
    18. 18. • Disrupting ecosystems can threaten biodiversity. • Hunting & gathering • Agriculture • Animal domestication • Urbanization
    19. 19. What happens?1. Urbanization – movement to cities – Outcome • Increased runoff causing flooding & erosion • Use of nonrenewable natural resources
    20. 20. What happens?2. Deforestation – Human destruction of forests – building of malls, homes, farming – Outcome • Loss of biodiversity • Soil erosion – loss of topsoil
    21. 21. 3. Overfarming – When plants are harvested soil becomes less fertile – Outcome • Abandoned fields • Erosion of topsoil
    22. 22. 4. Overgrazing – Herds of cattle & sheep overgraze grasslands – Outcome • Land has no cover & topsoil is eroded
    23. 23. 5. Misuse of Pesticides – Contaminate air, water & soil – Kill many organisms that aren’t pests – “Safe” pesticides have been found to be dangerous • DDT
    24. 24. 6. Biomagnification – Process where chemical becomes highly concentrated in the bodies of upper level consumers – How does this happen? – E.g. DDT became concentrated in bald eagles causing thin-shelled eggs that did not survive
    25. 25. 7. Invasive species – Introduction of organisms that are not native (natural) to an area • E.g. Purple loosestrife • E.g. Zebra mussels • E.g. Japanese beetles – Outcompete native species & take over • No predators • Able to use available resources better
    26. 26. Pollution You Stink
    27. 27. • Adding anything to the environment or affecting the environment in a way that makes it less fit for living
    28. 28. 1. Land Pollution• Tons of solid waste (refuse) are produced everyday• Sanitary Landfill• Incineration
    29. 29. 2. Water Pollution• Organic wastes – fertilizer runoff, sewage, waste from factories – Waste acts as food for algae, algae become overpopulated and lead to death of other organisms – Causes “eutrophication” • accelerated aging process/ succession
    30. 30. Water Pollution• Inorganic chemicals – Poisonous wastes dumped into waterways from cities, farms & industry – Biological Magnification • Mercury poisoning in Japan
    31. 31. Water Pollution• Thermal Pollution. – Warm water can’t hold as much oxygen as cool water. Organisms will suffocate & die
    32. 32. 3. Air Pollution• Burning Fossil Fuels – Burning of coal & gas – Cars, factories, electrical plants – Release CO2, sulfur, & nitrogen into the atmosphere – Cause health problems, acid rain, etc.
    33. 33. Air Pollution• Acid Rain – Occurs when sulfur & nitrogen combine with water – Forms in the rain, snow, & sleet – Lowers the pH of the water – Kills many producers Did you know that non- polluted rain is slightly acidic? The CO2 in the air forms carbonic acid when it rains…
    34. 34. Air Pollution• Smog – Produced from auto exhaust & industrial processes – Results in toxins that can be inhaled – Occurs when pollutants combine with sunlight
    35. 35. Air Pollution• Climate Change – Change in the climate (temp, precipitation, wind) last for an extended period of time. – Can occur naturally – Human activity & pollution can add to the effect
    36. 36. Air Pollution• Greenhouse effect Greenhouse effect – Occurs when sunlight passes through atmosphere gases • CO 2 , methane, H 2 O vapor – Gases trap & absorbs the sunlight resulting in an overall warming effect – Pollution can increase this effect The greenhouse effect is a natural and good process. Without it, the earth would be 30ºC cooler…
    37. 37. Air Pollution• Ozone Depletion (not global warming) – The ozone layer is made of ozone gas (O3) and is found between 20-50km above the Earth’s surface. – Absorbs harmful ultraviolet (UV) radiation from sunlight
    38. 38. • Ozone Depletion – CFCs (chlorofluorocarbons) cause ozone to break down • Found in aerosols, refrigerators, & air conditioners – Ozone holes form • UV light can enter atmosphere • Kills producers • Cause cancer Remember, ozone depletion does not cause the Earth’s temperature to increase!!!!
    39. 39. Natural Resources
    40. 40. Restoring the Environment – What can we do?• Nonrenewable natural • Renewable natural resource resources – coal, oil, natural gas, – air, water, soil, sunlight, metals, minerals living things – Can be taken from earth – Resources that are only once naturally replaced – Human activity can disrupt the natural events that replace the resources
    41. 41. Natural Resources• Conserving both renewable & nonrenewable natural resources is important – Sustainable use – use natural resources at a rate that does not deplete them.1. Recycling – Newspaper, glass, metal, plastic
    42. 42. 2. Conserving Soil• Soil is renewable, but the process is very slow, therefore it is important to conserve• Cover crops – Crops planted to cover a field to prevents erosion • Can also plant in between rows
    43. 43. Conserving Soil - HOW???• Crop rotation• Fertilizer• Strip cropping• Terracing• Contour Farming• Windbreaks
    44. 44. 3. Conserving Forests - WHY and HOW??? • Sustained-yield tree farming – Cutting down trees only in certain areas so surrounding areas are untouched. • Reforestation – Replace lost trees by planting new ones WHY???? • Forests provide wood, paper. • Soil holds large amts of water, prevent erosion. • Destruction takes a long time to replace
    45. 45. 4. Restoring the Environment - Conserving Wildlife • Cities & suburbs destroy natural habitats • Protection – Hunting/fishing laws – Game & bird preserves – Fish hatcheries breed fish & are restocked in heavily fished lakes – Pesticide & herbicide restrictions
    46. 46. Controlling Pests Biologically• More specific than chemical pesticides• Fewer adverse environmental effects• How ? – Import natural enemies • E.g. Ladybugs control aphids – Bacteria or virus that infect insect larvae • Gypsy moth caterpillars, mosquito larvae
    47. 47. Controlling Pests Biologically• Crop rotation – Remove favored food source…• Pheromones – Lure insect to trap & kill• Sterilization & release of male insects – Males become sterile by exposure to radiation – E.g. the screwworm fly only gets to mate once, so she is out of luck if she mates with a sterile males
    48. 48. 5. Controlling Pollution• Emission Controls for cars• Ban aerosol sprays• Control Industrial waste – Gas treated before released – Ban on dumping waste in water & land• Sewage treatment plants – Use bacteria to treat water before released• Reclaim strip mined land• Special sites for toxic waste
    49. 49. Restoring the Environment• Individual Actions – People can choose: • Not to pollute • Not to burn garbage • Change products that they use • Drive energy efficient cars – Car pool, use public transportation • Reduce, Reuse, Recycle
    50. 50. Restoring the Environment• Societal Actions – Cities, States, & governments can: • Pass laws against pollution • Fine or jail polluters • Hold public meetings & hearings about pollution • Give incentives - $$

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