biosphere/ecology Flashcards
what is climate determined by
- temp
- precipitation
- light
- wind
what are the biological hierarchies of ecology
- organismal
- population
- community
- ecosystem
- landscape
- global
what is a biome
major ecosystem type, classified according to predominant vegetation/environment
what are meromictic lakes
deep lakes that do NOT display water mixing (surface <–> bottom)
what are thermoclimes
vertical gradients in temp that prevent water mixing (cold bottom water, upper warm water)
what are turnovers in temperate holomictic lakes
moves oxygenated surface to bottom and nutrient-rich bottom water to surface
how does species distribution occur
depends on evolutionary history and biotic/abiotic factors
what is species richness
of species in a biological community
3 hypotheses that can explain latitudinal gradient in species richness
1) tropical latitudes receive more solar energy
–> longer growing season
2) fewer seasonal changes
–> facilitates competition and biodiversity
3) during ice age, temperate communities were vulnerable to glaciations
–> stayed undisturbed for longer
what are generalists
species that thrives in wide variety of environmental conditions
what are specialists
species that survive in narrow range of environmental conditions
what is dispersal
movement of individuals away from area of origin/ centers of high pop density
how to species living along an environmental gradient respond to climate change
- natural range limited by physiological factors
- natural range shifted north
- shrinkage of natural range
- adaptation to new conditions
define niche
all biotic/abiotic resources used by a species
–> realized niche<fundamental niche
what is competition
when 2 individuals of diff species compete for a resource
what is competitive exclusion
when populations of 2 similar species compete for the same resource, one will use the resource more efficiently
–> eliminates other population
what is resource partitioning
differentiation of ecological niches
–> decreases competition, allows species to coexist
what are trophic relationships
study of the structure of feeding relationships among organisms in an ecosystem
what can populations of intermediate trophic levels be controlled by
- amt of food in lower trophic levels (bottom-up control)
- presence of predators (top-down control)
what are keystone species
has large influence on species richness of community relative to its abundance
what is commensalism
occurs when one individual from one species obtains a benefit while individual from other species is neither hlped/harmed
