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Community Ecology Screen Shot 2020-11-05 at 1.31.50 AM - Coggle Diagram
Community Ecology Screen Shot 2020-11-05 at 1.31.50 AM
Predator–Prey Interactions
Predator Selection Among Multiple Prey
optimal diet model
four
predictions
if the high-yield prey
become sufficiently scarce
then
the predator would be
more successful by broadening
its diet to include prey
1 more item...
some prey items will
always be eaten if
they are encountered
others will never be eaten
predators should prefer
whichever prey yields
most energy
per
unit of handling time
probability that a particular plant will be eaten
depends partially on
abundance of other plants
optimal foraging theory
examine the interactions
between
these factors
Why do animals select certain prey over
others?
three imp factor in
predator’s choice of prey
decision by the predator to
attack an individual
it has been encountered:
Rare species will be
consumed less than abundant ones
cryptic due to coloration
smaller size may escape detection.
probability that
attacked prey item
will be successfully eaten
Competition Between Species
exploitation competition
Multiple species compete
with each other
for a resource
interference competition,
interaction of two species
one organism restricts another organism’s
access to resources
Two competing species
coexist in a community
if each interferes with
itself
more than it interferes with the other
other can increase from low density
even in the
presence of the other
One Predator, One Prey
primary producer
attacked by
one species of
predator
a primary consumer
functional response
predator’s feeding rate
and
handling time.
prey-dependent
dN/dt = rN – aNP
N=number of individuals of prey species in the community
a=predator’s per capita attack rate
r=intrinsic rate of increase for the prey species
P=the number of predator individuals present.
zero growth isocline
paradox of enrichment
maximum sustained yield
Apparent Competition
prey species
share a predator
If all prey populations
are low
then the population of the predator
probably low also
the increase of one prey species
may cause the decrease
other
prey species
not result of competition
Diversity
Diversity and Scale
common observation
scale matters
earth
our community
contains
every species
species-area relationship
S = cAz
S=number of species
A =area
c and z
known for
various communities
species abundance distribution.
no. of species
in a region
various abundance classes
the rest
rare
few
extremely common
Diversity and Latitude
diversity
varies with
latitude
oldest theory
most widely taught
tropical region near equater
relatively benign
environment
scale
size of the area being studied
larger areas have
more diversity
than smaller areas
Beneficial Interactions Between Species
mutualistic relationship
benefits both
facilitation
one helps another
without any benifit
Nurse plant
the presence of some plants
creates conditions that allow
other plants to
become established
provide
shade
camouflage
protection
primary succession
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organisms become established
on newly created substrates
Metapopulations in Patchy Environments
source habitat
high quality patch
sink habitat
low quality patch
fugitive species
survives by
colonizing new patches
flourishing temporarily
then colonizing more patches
before it dies out in old ones
assisted disperal
metapopulation
consists of several local populations
interconnected by
migration and gene flow
between the patches
Interconnectedness of Species: Food Chains and Food Webs
food chain
set of organisms
some are primary producers
others are
primary consumers
still others are
secondary consumers
direct line of consumption
food web
food flows
through the community
in a weblike pattern
energy flow web
keystone species
a species that
dramatically affects the
structure of its community
having an impact out of proportion
its size or the
number of individuals present
three trophic level
primary producers
plants, algae, cyanobacteria
primary consumers
herbivores
secondary consumers
carnivores
Concepts
community ecology
focuses on
members of
single species
interbreeding
survival
their growth
and more
succession
occurs in
many communities
more-or-less
predictable sequences
changes
climax community
remains
more-or-less the same
for many years
habitat loss
habitat fragmentation
community restoration
undergo
more-or-less predictable
sequence of changes
succesion
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