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22 Cards in this Set

  • Front
  • Back
What is an ecosystem? What two process occur within them?
All of the organisms that live in a particular place, plus their abiotic environment. Energy enters ecosystem, and chemicals move through ecosystems in biogeochemical cycles.
Describe the water cycle.
Water evaporates from bodies of water and transpires out of plants. It later precipitates out of the atmosphere. Some percolates in the soil and enters the groundwater.
What is groundwater? What is the upper portion of groundwater called? Why is groundwater important?
Water which occurs in aquifers underground. The water table. It is an important source of fresh water.
Where are some key locations of carbon?
The atmosphere, water, marine sediment, fossil fuels, and within organisms.
Describe the carbon cycle.
CO2 is respired and used in photosynthesis. It can also dissolve into water. Dead plants and animals can deposit carbon into fossil fuels, which can be burned, releasing CO2.
What three proteins catalyze the cleavage of atmospheric nitrogen (N2)?
Ferredoxin, Nitrogen reductase, and Nitrogenase.
What is amonification? What is denitrification?
The process of releasing excess nitrogen in the form of ammonium (NH4+) by prokaryotes and fungi. The conversion of soil nitrates into atmospheric N2 or N2O.
Describe the nitrogen cycle.
Atmospheric nitrogen is broken down by nitrogen fixing bacteria. Organisms consume the nitrogen and later deposit it. The deposited nitrogen is converted to nitrates and either is refixed or denitrified and released into the atmosphere.
Is the reservoir of nutrients in most biogeochemical cycles the atmosphere or rocks? Which nutrients are the exceptions?
Rocks. Water, carbon, oxygen, and nitrogen.
What is typically the limiting nutrient to plant growth? What is the second one?
Nitrogen. Phosphorus.
What is superphosphate?
Ca(H2PO4)2. It is used to add phosphorus to soil, but is generally used too much.
Describe the phosphorus cycle.
Phosphorus from rocks dissolves in water or soil, and is absorbed by plants and then animals. Decomposers return phosphorus to the soil and water.
What is a trophic level? What are the different trophic levels?
A category of animals within an ecosystem based on what they eat. Primary producers (autotrophs, plants), Primary consumers (heterotrophs, herbivores), Secondary consumers (carnivores), and Detrivores (scavengers and decomposers).
What is a food chain? What is a more accurate depiction of how biomass moves through an ecosystem?
A linear chain of trophic levels that feed on each other. A food web.
What is primary production/productivity? What is gross primary productivity? What is net primary productivity?
The amount of energy produced by the plants in a community. The total organic matter produced by plants, including that used for plant respiration. The total organic matter available to heterotrophs.
What is biomass?
The total mass of all organisms living in an ecosystem.
What is secondary productivity?
The rate of biomass production by heterotrophs.
What is trophic cascade? What are the two kinds?
The phenomenon of a trophic level having effects on other levels above and below it (i.e. carnivores influence plants by eating herbivores). Top-down and Bottom-up.
How does species richness seem to affect ecosystems?
Higher species richness tends to make ecosystems more stable.
What are some factors that affect species richness?
Ecosystem productivity, spatial heterogeneity, climate, and evolutionary age.
What is the species diversity cline?
The tendency to have more and more species richness the closer to the tropics an ecosystem is.
What is the species-area relationship?
Species richness appears to be greater on island of greater size.