Download Community Interactions

Community Interactions
Community = all biotica within a
defined area
Interactions
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*Predation
*Competition
Mutualism
Commensalism
Herbivory
Parasitism
*considered to be defining interactions within
ecosystems; research growing in other areas
Predation
• Predator/prey
• Often cyclic
Predation
• Predators have many adaptations for locating
and killing prey
• Can you name 3 of each?
• Prey also have many adaptations to avoid
being eaten
• Name 5
Competition
• Species compete for same niche
Interspecific
– Species competition keeps both populations in
check
– Hard to determine in wild, as would have to
eliminate one species to see how other
population reacts
– Easier in lab
Competition
Competitive exclusion
• The lesser adapted species is eventually
eliminated from niche
• Exotic / invasive species posing huge new
threats in this realm
Resource partitioning
– Resolves competition through
niche differentiation
– One species will adapt to a
certain range, or hunting time,
for example, to reduce full-on
competition
Competition
Competition
http://www.ib.bioninja.com.au/options/option-g-ecology-and-conser/g1community-ecology.html
Competition
Character displacement
– Species evolve slightly
different eating habits,
beak shape, etc, to
differentiate within
habitat
– Allopatric populations
(geographically
separate) can be seen
to have more similar
characteristics than
sympatric (overlapping)
populations
Herbivory
• Herbivores eating producers
Parasitism
• Ecto – external
• Endo – internal
• Parasitoidism – lay eggs for young to feed
Disease
• Interaction because disease is caused by living
pathogens
• Related to parasitism
• Pathogens:
– Fungi
– Bacteria
– Viruses (sort of, but not really alive)
– Protists
– Prions (proteins)
Mutualism
Win-win
Commensalism
• Win/eh
• debated