Bio 1215- Chapter 17
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Bio 1215- Chapter 17
all organisms within a particular area
Interspecific interactions include what 7 things?
the sum of a species use of the biotic and abiotic resources in its environment
(how and where it makes its living)
what is the
competitive exclusion principle
2 species cannot occupy the same ecological niche
how does competition allow the competitive exclusion principle to exist? (4)
a superior competitor
may drive other species to extinction
limit a species to a more limited niche than it might otherwise occupy
species with similar niches
may come to subdivide the niche
may push sympatric populations of 2 species to become diff
species with similar niches may come to subdivide the niche
what is character displacement? what is an example?
direct competition may push sympatric populations of 2 species to become different
ex. diff bird beaks reflect diff seed sizes
what is predation? what can it drive?
one species kills the other and eats it
can drive evolutionary "arms race"
how have predators evolved? (4)
good sensory systems
how have prey evolved? (6)
how may defenses of predator and prey advertised?
describe the 2 different types of mimicry.
several dangerous species resemble each other
a harmless species resembles dangerous one
when plant or algae is partially consumed
what are some plant adaptations to herbivory?
spines or hairs, cuticle, thick bark fro grittiness
what are some herbivore adaptations to herbivory?
ability to detect plant (smell, colour, shape)
ability to overcome host defences
parasite harms the host (doesn't kill right away)
Describe the 2 types of parasites. what are some examples?
found on outside of the host ex. leeches, lice
feed inside of host ex. flukes, tapeworms
what is the lifecycle of flukes? (6)
fluke eggs (in bird feces) land in water
snails eat feces
flukes exit snails into water
flukes frill into fish
fish eaten by birds
fluke eggs in bird feces
what is the fluke lifecycle consequence to crabs? (5)
infected snails grow slow and reproduce less= less snails
less algae eaten by snails=more algae
more cover for remaining snails
harder for crabs to find snails= less crabs
what is diseases? what can it cause?
mostly due to microscopic pathogens
: viruses, bacteria, fungi, protists
can cause decline of susceptible host species
what is mutualism? what is an example?
evolved interactions that favour both species
flowering plants and pollinators
what is commensalism?
one species benefits; other neither gains nor loses
Most of the preceding interactions have been shaped through ____________.
what is species diversity? what are the 2 components?
variety of diff kinds of organisms
(# of species) and
relative abundance of each species
Energy and nutrients flow through __________ or _________.
Are there limits to food chain lengths? why?
limited length because energy transfer between trophic levels is usually <20% efficient therefore not enough energy to support many trophic levels
what are the 4 community characteristics?
the role of one or two key species (species with large impact)
response to disturbance
what is a dominant species?
are most abundant or have greatest biomass
influence with other species, can survive there
what are keystone species?
need to be abundant but act to maintain diversity
what are ecosystem engineers? what is an example?
ecosystem engineers cause physical changes that affect community structure
beavers building dams and termites
what is ecological succession?
gradual, predictable change in community structure after a disturbance
what is primary and secondary succession?
primary succession= gradual, predictable change in community structure after a disturbance that
begins from bare rock
secondary succession= gradual, predictable change in community structure after a disturbance
that begins from intact soil
why does succession occur?
each stage creates conditions that favour the next stage or inhibits members of current stage
Is a finals Climax community ever reached?
yes to an extent
community diversity is affected by _____________________.
There is greater diversity in ________ habitats. why? (2)
more energy and maybe a more stability
more species in bigger communities
what does they island equilibrium model predict?
predicts that species number is related to "island" size and distance to a "mainland"
More species on an island, lower __________________________. why?
lower the arrival rate of new species
most of these species are already on the island
more extinctions (of new arrivals) because more competitive exclusion
what are the implications for conservation? (3)
immigration and extinction rates
effect of island size
effect of distance from mainland
what are the 2 hypothesis that suggest why certain communities exist and not others?
plant species there simply have similar ecological requirements
community is an association of ecologically-linked species interact in some way