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BSC 108: FINAL EXAM REVIEW
Food Chain |
The sequence of food transfer from trophic level to trophic level.
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Food Web |
The feeding relationship in an ecosystem. They are usually woven into elaborate chains.
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What % of energy is passed up each subsequent trophic level? |
10%
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Biogeochemical cycle |
In ecology and Earth science, a biogeochemical cycle or nutrient cycle is a pathway by which a chemical element or molecule moves through both biotic and abiotic components of Earth.
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3 main points of biogeochemical cycle |
1. Each circuit has an abiotic reservoir.
2. A portion of chemical cycling can rely completely on geological processes. 3. Some chemical require processing before they are available as inorganic nutrients.
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Major abiotic and biotic reservoirs for Carbon |
abiotic- atomosphere
biotic- animals
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Major abiotic and biotic reservoirs for Nitrogen |
abiotic- soil
biotic- bacteria, plants
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Major abiotic and biotic reservoirs for Phosphorous |
abiotic- rock
biotic- plants, detritivores
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Biomes |
the major types of ecosystems that cover large geographic regions of the Earth.
Terrestrial: Tropical forest, savanna, desert, polar ice, chaparral, temperate grassland, temperate deciduous forest, coniferous forest, and tundra (arctic and alpine) Aquatic: photic zone, aphotic zone, and benthic zone (standing bodies of water, rivers and streams, wetlands) Marine: Oceans, Estuaries
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Photic zone |
includes the shallow water near shore and the upper stratum of water away from shore. (light is available for photosynthesis)
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Aphotic zone |
Deeper water, where light levels are too low to support photosynthesis
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Benthic zone |
bottom of all aquatic biomes
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Rivers and streams |
bodies of water flowing in one direction.
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Oceans |
cover 75% of the planet's surface
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Estuaries |
areas where a freshwater stream or river merges with the ocean.
one of the most biologically productive environments on Earth.
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Marine life is distributed according to: |
1. Depth of the water.
2. Degree of light penetration. 3. Distance from shore. 4. Open water vs. bottom.
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Oceanic zones |
Intertidal- the area where land meets water
Photic- top of water that enough light penetrates for photosynthesis. Aphotic- water where light does not penetrate at levels for photosynthesis Benthic- oecan bottom/seafloor Pelagic- open ocean
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Monoculture |
a population of a single kind of organism
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Introduced species |
Introduced species are those that humans intentionally or accidentally move from the species' native locations to new geographic regions.
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What species has the greatest impact on communities worldwide? |
HUMANS
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How have humans impacted the biosphere? |
Human distrubance of biological communities is almost always destructive.
Human disturbance usually reduces species diversity in communites.
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How have humans impacted chemical cycles? |
Human activities often intrude in biogeochemical cycles by removing nutrients from one location and adding them to another.
C- increasing burning of fossil fuels is steadily raising the level of CO2 in the atmosphere. N- sewage treatment facilities and fertilizers add large amounts of nitrogen to aquatic systems, causing heavy growth of algae. P- sewage treatment facilities and fertilizers also add large amounts of phosphates to aquatic systems, causing eutrophication.
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Eutrophication |
Eutrophication is an increase in the concentration of chemical nutrients (P) in an ecosystem to an extent that increases the primary productivity of the ecosystem, so much so that it hurts the ecosystem.
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How have humans affected the release of toxic chemicals into ecosystems? |
Humans have added to ecosystems new toxic materials, which often cannot be degraded by microorganisms.
Toxic substances are acquired by orgs from the environment along with nutrients and water. May be metabolized, but can also accumulate in specific tissues.
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Biological magnification |
a process in which toxins become more concentrated in successive trophic level of a food web.
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What is the evidence supporting global climate change? |
Since the Industrial Revolution, the concentration of CO2 in the atmosphere has been increasing due to the burning of fossil fuels and wood and to deforestation.
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The greenhouse effect |
retains solar heat in atmosphere
produced by CO2 and water vapor in the atmosphere.
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Ozone layer
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The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O3).
It absorbs UV radiation, preventing much of it from contacting organisms in the biosphere.
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Ozone depletion |
Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4% per decade in the total volume of ozone in Earth's stratosphere (ozone layer) since 1975, and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions during the same period.
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Biodiversity crisis |
a precipitous decline in Earth's great variety of life due to the effect of human activity on communities and ecosystems.
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3 main components of biodiversity |
1. The diversity of ecosystems.
2. The variety of species that make up the biological community of any ecosystem. 3. The genetic variation within each species.
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Endemic species |
Endemic species are unique to a particular geographic location, such as a specific island, habitat type, nation, or other defined zone.
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Conservation biology |
conservation biology is a goal-oriented science that seeks to counter the loss of biodiversity.
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Biodiversity hot spot |
a relatively small area with an exceptional concentration of species.
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Endangered species |
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters.
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Threatened species |
Threatened species are any species which are vulnerable to extinction in the near future.
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Population fragmentation |
the splitting and consequent isolation of portions of populations by habitat degradation.
This is one of the most harmful effects of habitat loss due to human activities.
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Source habitat |
one of good quality where a subpopulation's reproductive success exceeds it death rate.
These habitats can produce enough individuals that some disperse to other areas.
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Sink habitat |
one of poor quality where the subpopulation's death rate exceeds it reproductive success.
Dispersal of individuals to sink habitats b/c of habitat loss can sometimes threaten the survival of subpopulations in source habitats.
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Landscape ecology |
Landscape ecology is the application of ecological principles to the study of land-use patterns
" " is the science of studying and improving the relationship between spatial pattern and ecological processes on a multitude of landscape scales and organizational levels.
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How do edges and corridors affect communities? |
Edges between ecosystems are prominent features of landscapes and can be natural or caused by humans.
They can have both pos and neg effects on biodiversity.
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Movement corridor |
a narrow strip or series of small clumps of quality habitat connecting otherwise isolated patches.
Corridors can promote dispersal and help sustain populations. These are especially imp to species that migrate between different habitats seasonally.
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Sustainable development |
balances human needs with the health of the biosphere.
The goal of sustainable development is the long-term prosperity of human societies and the ecosystems that support them.
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