Download Community Ecology

COMMUNITY
ECOLOGY
Chapter 37.1 – 37.6
What you need to know!
• The community level of organization
• The role of competitive exclusion in interspecific competition
• The impact of keystone species on community structure.
• The symbiotic relationships of parasitism, mutualism, and
commensalism
Community
• All the organisms of various species that live close enough to
interact
4 characteristics:
1. Species diversity: variety of species
a) Species richness = total number of species
b) Species abundance = the amount of each species
i.e.
Community 1: 25 A
25 B
25 C
25 D
Community 2: 97 A
1B
1C
1D
2. Dominant Species: typically most abundant species
3. Response to disturbance: ecological succession
4. Trophic structure: energy, feeding relationships, nutrient cycles
Interspecific Competition
• Competition between species for resources that share the same
habitat
• Predators competing for prey
• Plants competing for soil
• Habitat: where the organism lives
• Niche: what the organism does in its habitat
• Competitive exclusion principle: no two species can occupy the
same niche in the same habitat at the same time
• https://www.youtube.com/watch?v=KyPstXBKALY
• Resource partitioning is when organisms live in different regions of
the same habitat so they cancoexist (realized niche)
Predator and Prey
• Keystone species exert strong control of an ecosystem
• Keystone predators tend to reduce the population of the strongest
prey species
• This provides an opportunity for lesser species to find niches within the
habitat
• https://www.youtube.com/watch?v=ysa5OBhXz-Q
Unique adaptation:
• Camouflage developed as a result of predation
• Chemical defenses are common among dangerous prey
• Batesian mimicry is when something harmless looks like something
harmful
• Müllerian mimicry is when two harmful species look similar
Symbiosis
• Close relationships that develop through coevolution (evolving
together)
3 types
1. Mutualism: both species benefit
2. Commensalism: one species benefits
3. Parasitism: one species benefits the other is harmed
Which one?
• http://www.naturefootage.com/video_clips/NZ47_018
• http://video.nationalgeographic.com/video/player/animals/bugsanimals/ants-and-termites/ant_caterpillarsymbiosis.html