Biology CH 43.

• Adding nutrients to stimulate plant growth should increase biomass at higher levels is a concept of bottom-up control
• Altering biomass at trophic levels will change community structure is a concept of bottom-up control
• Influences occurs from lower to higher trophic levels is a bottom-up control
• Predation that occurs control community structure is a top-down control
• Higher trophic levels have direct and indirect effects on the lower levels is a concept of top-down control
• top-down control: Predation can have negative or positive indirect effects on the producers of an ecosystem
• The variety of species in an ecosystem is the species diversity.
• Ecosystem diversity represents the variety of ecosystems in a region or on Earth
• The number and relative frequency of alleles in a population is the population's genetic diversity.
• Extinction Vortex is an decrease in genetic variance which leads to a decrease in "population adaptive potential", and eventual extinction.
• Biological Manipulation the deliberate alteration of an ecosystem by adding or removing species, especially predators.
• Biological Magnification is the process of accumulation of certain chemicals in living organisms to a concentration higher than that occurring in the inorganic, non-living environment.
• Habitat fragmentation is fragmented or broken habitat or ecosystem.