Download Competition, lecture 10a (extra)

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Lecture Topic:
Basic ecological principles of
competition and the associated affects
on marine community structure
A Biological Community is “all of the populations of organisms living together (and
potentially interacting) within the ecosystem.”
Community:

(a)
(b)
(c)
Within a community you have interactions
among the species themselves that can
lead to:
Predation
Symbiosis
COMPETITION
What is competition?
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

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
“A contest among organisms in the demand for a
necessary resource that is in short supply.”
a. Interspecific
b. Intraspecific
c. Predator-Prey
d. Within a plant community
EXAMPLE #1:
Zonation and
Interspecific“Competition”
in a Barnacle community
“Rocky Intertidal” (LIS)
The 2 barnacles occupy different niches, Upper limits of Balanus set by water,
while lower limits of Chthamalus set by Competition.
(If you remove Balanus, then Chthamalus will move lower but it typically
cannot because it gets out-competed).
EXAMPLE #2:
Predator-Prey “Competition”
between a mussel and sea star
Predator-Prey Dynamics can influence a community, leading to diversity
Pisaster: A “keystone predator”
EXAMPLE #3:
ZONATION and “Competition”
IN THE (TIDAL WETLAND)
PLANT COMMUNITY
High Marsh
Low Marsh
Shoal/Mud Flat
<-- Iva frutescens (Marsh Elder)
<-- Distichlis spicata (Spike Grass)
(low vigor) S. alterniflora (I
Phragmites
Juncus ->
Again…DIVERSITY!!!
IM cont.
Transition Zone: Upland (Phragmites) to
Intertidal Marsh (S. alterniflora) to Wetland
There can even be
“zonation”
between
a plant and
animal
species.
Species Diversity is EVERYWHERE…
Now get out there and see what you can find!