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Chapter 26 Community Ecology (Community # (climax community (spruce-fir…
Chapter 26 Community Ecology
Community
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a group of species that occur together at the same time and place
population biology focuses on the members of a single species, their growth, interbreeding, survival, etc
must have boundaries in both time and space
entire forest is a a community
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spatially defined by any factor that keeps the trees from growing
boundaries in time
they come into being and then cease to exist
climax community
spruce-fir forests that cover thousands of miles
alter the environment so that they are the only species that benefits
fire/landslide occurs and the aspen is the pioneer but changes the land so that it is suited perfect for the spruce-fir trees
succession
more or less predictable sequence of changes
community restoration
reintroducing wolves into yellowstone
and encouraging the migration of bears and mountain lions into big bend from the rio grand
habitat loss and habitat fragmentation
due to farming, building, and mining
diversity
measured by quantifying species richness
a species count is made called a checklist
diversity of growth forms may be the focus such as the presence, absence, and relative abundance of
shrubs
trees
herbs
annuals
perennials
study the feeding methods of herbivores and plant organs
Diversity and scale
scale
scale matters
larger areas are more diverse than smaller ones
a larger area will have more diverse populations than a smaller one
species area relationship
the relationship between are and species richness is
expressed by the formula S=cA^2
S is number of species
A is the Area
c and z are constants that must be discovered by studying individual communities
species abundance distribution
we can plot the number of species in each abundance class
species abundance distributions do nit describe most communities accurately
high latitudes have lower diversity than equilateral ones
evolutionary history is a fundamental contributor to the differences and diversity between tropical and high latitude areas
Predator-Prey Interactions
one predator, one prey
plant vs herbivore
primary producer attacked by primary consumer
useful because it helps us understand how human predators should harvest or various prey, such as fish, deer, lumber
two fundamental aspects of predator-prey relationships are he predators deeding rate and its handling time
feeding rate rate refers to how quickly a predator dins a new prey individual and handling time refers to the amount of time needed to consume the prey
make up the predators functional response
feeding rate will be faster If there are more prey individuals available so a predators functional response is dependent on prey density
prey-dependent
if the predator population is sparser than that of the line the prey population will increase if predator population decreases
the kine indication population stability is called zero growth isocline
Predator selection among multiple prey
Predators choice of prey
attacking the individual once encountering
will the prey be successfully eaten
particular prey encountered
interference competition
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competition between species
competing for the same resources
exploration competition
organisms eating the same resources
makes it harder for other organisms
optimal foraging theory
the interaction between choice of prey factors
figuring out why herbivores only certain types of plants
apparent competition
there are decreases in the other species
all prey low
then predator count will be low
plants are competing
Apparent Competition
metapopulations in patchy environments
sink habitat
a low quality patch environment
fugitive species
colonizes more patches
florist temporarily
survives by colonizing new patches
source habitat
an ideal, high quality patch
assisted dispersal
animals are captured
both are relocated
seeds are moved in plants
multiple localized populations
migration also plays a factor
connected by gene flow
theres migration between these patches
within a patch you'll have both animals and plants obviously
animals traveling by flying, walking or swimming, this transports seeds or spores from patch to patch
global warming
empty patches
no surpluses or spare, or they are unneeded
Beneficial interactions between species
mutualism
both of the organisms benefit
pollinators and the plants they pollinate are an example
primary succession
organism becomes established
Newley Created substrates
volcanos form substrates
lava flow and ash fields that are sterile as they cool
or glaciers that scrape away substrate
need pioneer species like moss and lichens to rebuild
or species with slender roots
nurse plants
alter a small area of habitat immediately below themselves such that it is more favorable to the survival seedlings of other plants as compared to other nearby areas not below nurse plants
facilitation
one organism helps another without any benefit
organism facilitates the presence of another
