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40 Cards in this Set

  • Front
  • Back
Species richness
the number of species that a community contains
Relative abundance
the number of animals within each species in a community
a group of populations in the same habitat at the same time
Individualistic hypothesis (Gleason)
plants live where they do because of abiotic factors regardless of other plants
Interactive hypothesis (Clements)
a community is a group of linked species that work as a unit
Rivet model
similar to Clements' interactive plant theory, except for with animals. Species are closely linked
Redundancy model
most species aren’t closely linked, as suggested by Gleason for plants. One animal will take the niche of another if necessary.
Intraspecific Interactions
interactions between the species of a community
Intraspecific Competition
competition over resources (food, mates, territory)
Competitive exclusion principle
two species so similar that they complete for the same limiting resource cannot coexist in the same place
Ecological niche
sum total of a species use of biotic and abiotic resources (how an organism fits into it’s ecosystem)
Resource Partitioning
if two species have the same niche the less competitive one will either be driven from the area or will evolve through natural selection to use a different set of resources
Character displacement
the tendency for characteristic to be more divergent in sympatric population of two species than in allopatric populations of the same two species. The evolution of one species so as to avoid competition between the two.
good for one bad for the other (includes herbivory and parasitism)
Predator Adaptations
acute sense to locate prey (claws, teeth, poison, speed)
Plant Defenses
chemical toxins, thorns (because a plant can’t run)
Passive Defenses
toxins hiding
Active Defenses
running, defending, warning calls
Adaptive coloration (4)
adaptive (camouflage, aposematic coloration) and mimicry (batesian and mullerian)
blending, color changing
Aposempatic coloration
bright colors to scare others
Batesian mimicry
a harmless species mimics a harmful one
Mullerian mimicry
some toxic animals have the same colors (like bees)
live in host, deadly
feed on eternal surface (mosquito)
lay eggs on host
beneficial to both species. They often adapt together if suffer together.
beneficial to one and has no affect on the other
Trophic structures
feeding relationship between organisms
Food chain
transfer of food energy from its source in plants through herbivores to carnivores and eventually to decomposers, each link makes a trophic levels. Each food chain only has four of five links because of inefficient energy transfer. Recovery from disturbances may be harder at the top.
Dominant Species
highest abundance of biomass (control over other species’ distribution)
Keynotes species
exert control on the community by their niche rather than umber. May help to protect diversity or balance.
storms, fires, floods, drought, overgrazing, human activities. May upset community balance.
Ecological succession
how the composition of a community changes after a disturbance or on new land
Primary succession
beings in a virtually lifeless area without soil
Secondary succession
begins in an existing community that has been cleared by a disturbance that leaves soil
how many species in a community
species richness, how many of different species in a community
Species richness on islands
depends on the size and distance from mainland
Why do tropical habitats support more species than polar or temperate habitats? (5)
1. longer growing season 2. tropical communities are generally older than polar ones 3. biological time is faster in tropics 4. fewer major disturbance sin tropics 5. Solar energy input is higher in tropics as is water availability