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Community Ecology - Coggle Diagram
Community Ecology
Metapopulations in Patchy Environments
makes four assumptions
A region of the environment
composed of
discrete patches where
species can live
Some patches are occupied by species
whereas
suitable patches are
not.
Populations within individual patches
probability of going extinct within
that patch
Empty patches will become colonized
migration from occupied patches.
The high-quality patch is a source
habitat
low quality patch is sink habitat
Population sizes always vary
with time due to predators, competition, and
disturbance
Empty patches are
not surplus
fugitive species
survives by
flourishing temporarily
colonizing more patches
before it dies out
colonizing new patches
assisted
dispersal
animals are captured in one area
released into the new area
Beneficial Interactions Between Species
Many pioneers associations with nitrogen-fixing
bacteria
primary succession
Facilitation plays a role in succession
facilitation,
one organism
helps another without benefit
mutualism
two organisms interact to benefit both
Eg: pollinators
Diversity
Diversity and Scale
species-area
relationship
Alpha diversity
growth forms that occur at a local
Beta diversity
differences between small sites within a larger
region.
Gamma diversity
number of species within a region
Larger areas
have more variation
have more types of organisms
higher diversity in larger areas
more diverse than smaller ones
species abundance distribution.
Predator–Prey Interactions
Predator Selection Among Multiple Prey
Three factors important in a predator’s choice of prey
the decision by the predator to attack
an individual once it has been encountered
probability that an attacked prey item will be successfully eaten
probability that a particular prey individual will be encountered
Competition Between Species
interference competition
organism restricts another organism’s
access to resources
exploitation competition,
organisms
consume a shared resource
Apparent Competition
the prey species share a predator.
prey populations are
low,
means
population of the predator is probably low
plants are not competing using a resource
One Predator, One Prey
Lotka-
Volterra model.
net rate of change in prey numbers as
dN/dt = rN – aNP
the predator population will be stable when the density of prey equals
equation for the net rate of change of predator number
P/dt = faNP – qP
helps to understant harvesting process of prey
Diversity and Latitude
varies in latitude
provide idea of process of community ecology
tropical regions have relatively benign environment
Interconnectedness of Species: Food Chains and Food Webs
three trophic levels
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primary consumers
herbivores
secondary consumers
carnivores
primary
producers
plants, algae, cyanobacteria
study of species interaction across trophic level
direct line of consumption- food chain
network of numerous
interrelationships - food web
keystone species
Species - Area relationship
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Relationship between area and species
S=cAsquare
Fixed efforts harvesting
Fixed quota harvesting
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Have maximum sustained yelid
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