Bio Chp 35
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What is an ecosystem?
community of organisms + the physical enviornment with which they interact
What is biotic? what is abiotic?
- Biotic = living
- abiotic = nonliving
What are some major abiotic facors to an ecosystem?
Temperature and precipitation are the twop two affectors of ecosystems
- Resources: Nutrients
- Condidtions: temperature
what is biogeochemical cycling?
the movement of water and nutrients between the biotic and abiotic world
"nature's form of recycling"
How does carbon get returned back to the environment?
- CO2 is released during respiration
- CO2 is released during composition
What is the carbon cycle?
- 1. photosynthesis
- 2. respiration
- 3. dead organisms
- 4. fossil fuels
- 5. burning of fossil fuels
What are the 2 main roles of carbon?
- makes up portion of atmosphere
- It feeds everyone
- impacts global temperature
What is the nitrogen cycle?
- 1. nitrogen fixation
- 2. assimilation into plants
- 3. decomposition by bacteria and fungi
- 4. nitrifying bacteria
- 5. denitrifying bacteria
Some harmful effects of Nitrogen
: industrial process for nitrogen fixation that converts N gas into formas plants can use
-Humans are n-fixers
: they are #1 n-fixers in the world
- -nutrient pollution: runoff from agricultural lands.
- excess nitrogen results in "dead zones" where life is unable to grow
evaporation, precipitation, H2
Where is water stored?
Glaciers and polar ice
How much freshwater is there?
- 2.5% of all water on Earth
- 25% of that freshwater is groundwater
What is a wetland?
an ecosystem that is wet for at least part of the year. It also can be under a permanent cover of water
examples: swamps or marshes
What is the imporance of wetlands?
- very productive and imporant habitats for migratory birds
- filtering systemof the world
"kidney's of the earth"
Why is there water scarcity?
- inefficient use of water (bad agricultural practices)
- humans are using a larger proportion of water (more people)
What are the two laws of energy?
- The law of conservation: energy never gained or lost, only transformed
- The law of entropy: energy always flows from more-ordered to less-ordered state
what is the least orderly state of energy?
What are trophic levels?
different feeding levels.
- There are two types: producers & consumers.
- Producers: plants and other photosynthesizers
- Consumers: all other organisms
Why do trophic levels get smaller?
- -not all members consumed
- -some energy is lost throughout the process
- -for each jump in trophic level, the amount of available energy drops 90%
What are detritivores?
consumes dead or "cast off" organic matter. Detritivores break down inorganic componenets that can then be recycled.
what is the energy-flow model?
Measures energy as it is used by and transferred among different members of an ecosystem
Why are large, predatory animals rare?
- very little solar energy assimilated by plants is avaible to the higher trophic levels
- not enough energy to have a big population
What is the atmosphere?
layer of gases surrounding the Earth.
- Composed of:
what is the troposphere?
lowest atmospheric layer, contains most of the gases
- 99% nitrogen and oxygen
- small amount of CO2
other trace gasses: argon, methane, etc.
What is the stratophere?
higher up, contains ozone layer (O3)
What is the ozone layer?
a layer of gasses that screens out 99% of the sun's UV radiation.
How can the ozone layer be depleted?
by the use of human-made compounds
- Chlorofluorocarbons (freon) : found in refigerators
CFC's converted the ozone layer into O2
What is the Earth's tilt impact on climate?
since the earth is tilted at 23.5 degrees there are different types of climates found throughout the world.
- Changes in:
What are circulation cells?
Patches of moving air that are greatly affected by the differences of warming.
- rains where it rises
- dry where it descends
What is climate?
average weather condition in a given area.
(helps dicate what the biotic world looks like)
how certain are scientists about global warming?
at least 90%
What are a biomes?
large terrestrial regions of the earth that have similar climates and hence similar vegetative formations.
What are the six different biomes?
- Temperate deciduous forest
- Temperate grassland
- Tropical rain forest
What is the greenhouse effect?
where gasses such as CO2 and methane trap heat that comes to the Earth from the sun. Thus warming the Earth much the same as a greenhouse
What are the primary drivers of global warming?
- Burning of fossil fuels
What is the projected range of temperature due to global warming?
an increase by 1.8 degrees C to 4.0 degrees C
What are the effects of global warming
- Glacial melt
- sea level rise
- more "extreme" conditions
- habitat loss - species loss
- ocean acidification
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