Humans and the Biosphere/Populations
Humans and the biosphere Can result in species extinction
Can result in · Biodiversity = The sum total of all endangered species organisms in the biosphere. The splitting of ecosystems by developing Habitat fragmentation lands Threats to biodiversity
Biological Over hunting magnification = Human activities concentrations of a harmful substance increase at higher trophic levels in a food chain or Pollution Example: DDT food web. Invasive species A pesticide
Resulted in a A foreign species, without sever drop in the Reproduces rapidly any natural predators, bald eagle population introduce into an and negatively affects the environment. ecosystem.
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Renewable resources= Humans and can be replenished (ex. the biosphere trees, grass, water) Sustainable development = A way of using natural resources without depleting them and of providing for human needs Non-renewable resources= without causing long term cannot be replenished (oil, coal environmental harm. natural gas)
Topsoil=the nutrient rich upper Land resource layer of soil Resources threats Erosion=the wearing away of the surface soil by water Forest resource and wind threats
Fishery resource Desertification=Land turns into Due to farming, threats Deforestation=loss of the forest barren desert overgrazing, drought
Overfishing=harvesting Leads to erosion fish faster than they are able to reproduce
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Pollutant = harmful material that can enter Humans and the biosphere through the land, air or water. the biosphere
Air resource Smog = mixture of pollutants that occur threats as a gray-brown haze in the atmosphere.
Acid rain=Nitrogen and Sulfur combine with Freshwater water vapor to form nitric resource threats and sulfuric acid
Pollution
The fish and shellfish Sewage and fertilizer die runoff increase the nitrogen and phosphorus in lakes, river and oceans All of the oxygen is used up by the bacteria Can lead to Eutrophication The algae die Promotes the overgrowth and aerobic bacteria of algae decompose the algae
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Humans and The burning of the biosphere Global warming-An increase fossil fuels and the in the average temperature cutting down and burning of the biosphere of forests has led to an increase in carbon dioxide in the atmosphere
Ozone layer The increase in carbon dioxide has resulted in more heat being trapped Ozone gas in the High levels of UV upper atmosphere in the atmosphere due radiation can damage to the greenhouse effect protects life from life on earth ultraviolet radiation
As a result Chlorofluorocarbons (CFCs) CFCs were used as a the global temperature damage the ozone layer. propellant in aerosol cans and has increased as a refrigerant in refrigerators
High levels of CFCs has led to a hole in the ozone layer · Melting polar ice above the arctic · Sea levels may rise and flood coastal areas. · More droughts during the summer. · Organisms may not be able to survive Today most uses of CFCs are the climate change. banned
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· Geographic distribution = Populations Characteristics of Area inhabited by a population. · Population density = number Birth a population of individuals per unit area. · Growth rate Deaths
Factors that number of affect population individuals Logistic growth=Growth of a growth Growth patterns population slows or stops Immigration = the movement of individuals into an area.
· Birthrate decreases Emigration=the Exponential growth=individuals · Death rate increases movement of in a population reproduce at a Follows a period of · Birth rate and death rate equal each individuals constant rate exponential growth other out of an area · Rate of immigration decreases · Rate of emigration increases
Carrying capacity=The largest number of individuals that an environment can support
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Competition for Populations resources Factors which Density-dependent become limiting limiting factors when the population density Predator-prey reaches a certain level relationships
Limits to population growth Parasites and disease
Density-independent Unusual weather limiting factors Factors which affect the Human population population regardless growth of the population size natural disasters
Human activities Demography=the scientific study of human populations
People begin to have Advances in nutrition, fewer children. This is medicine and sanitation called the demographic lowers the death rate transition
The birth rate falls The population increases and population growth slows rapidly at this time
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