Lecture 22 Flashcards
what is the definition of ecology
the study of the interactions of organisms with each other and with their physical environment
what are the trophic levels
primary producers, primary consumers, secondary consumers
what is the pyramid for trophic levels
energy, biomass, and numbers
what is the definition of energy in the trophic levels
approximately one-tenth of the energy incorporated in one trophic level is incorporated into the next (some lost as HEAT)
what is the definition of biomass in the trophic levels
the total organic matter
how is the energy flow complicated
many species fall into more than one trophic level; many are specialized and able to utilize only one or a few species as a source of food; others utilize many species, switching among them as they prey vary in abundance
what is competition
an interaction in which two or more organisms are utilizing a required resource available in limited supply; drives natural selection
how is competition important for growth rate
helps plants compete for light, water, and minerals
what is the principle of competitive exclusion
holds that one or the other species must eventually be eliminated when they have similar requirements
what does competition favor
specialization
what is competition affected by
herbivory and environmental stressors
what is the definition of mutualism
a biological interaction in which the growth, survival, and reproduction of both interacting species are enhanced
what is coevolution
species mutually evolving to exploit the benefits of cooperation
what are the type of plant defenses
against herbivory, against pathogens, incredibly complex
what type of plant defenses against herbivory do they have
produce toxic chemicals, spines and thorns, tough leathery leaves
what type of plant defenses against pathogens do they have
phytoalexins
how are plant defenses incredibly complex
monarchs gain defense, sex attractants in insects
what is succession
the change in a community over time, the predictable process of recovery after disturbance of an ecosystem, used in restoration ecology
what are biomes
type of vegetation that is reasonably homogeneous over large terrestrial areas
what are biomes determined by
climate: temp and precipitation ; importance of elevation and latitude
what are characteristics of rainforests
constant temp, consistent rain, nutrients ample, high diversity, no fires but evolved to withstand winds
what do plants compete for in rainforests
light
what are characteristics of savannas and deciduous tropical forests
seasons that receive less rain, fires common
what are characteristics of deserts
high temps, precipitation is low, perennial plants adapt by: storing water, going dormant, or gaining access to deeper water, some plants have annual growth patterns
what is a transition zone
not enough rain to form a grassland but more than the desert
what are characteristics of grasslands
not enough rainfall to support major tree growth, grasses regrow from basal meristems, fire important, can be overgrazed and covered to deserts
what are characteristics of temperate deciduous forests
warm summers, cold winters, 75-250cm annual precipitation
what are characteristics of temperate mixed and coniferous forests
colder winters and more reliable snow cover
what are characteristics of alpine tundra
cold high elevations
what are characteristics of mediterranean scrub
cool wet winters, hot dry summers, fire is a factor
what are characteristics of taiga and boreal forest
mostly short and extremely cold days and very short growing season with long days, acidic low nutrient soils, low diversity, low precipitation but surplus of moisture because of low evapotranspiration, permafrost
what are characteristics of the arctic tundra
1/5 of land surface, cold damp soils, low productivity, treeless biome, relatively small number of plant and animal species, alpine tundra
