c5: population ecology
Migrationcengage chapter 5: population ecology
Five main types of species interactions:
- interspecific competition
- predation
- parasitism
- mutualism
- commensalism
Interspecific competition: two species, niches overlap, compete for resources (e.g. humans and many animals)
Resource partitioning: one resource is shared by species, but in progressdifferent ways:
Predation: predator-prey (one always dies, the other survives)
See also predator prey growth cycles
Predator strategies:
speed (e.g. cheetah)
teamwork (e.g. lions)
camouflage (e.g. praying mantis)
chemical warfare (e.g. spiders)
Prey survival strategies:
speed (gazelle)
senses (sight, sound, smell)
physical (shells, spines, thorns)
camouflage (arctic hare)
chemical warfare (octopus)
mimicry (looking like something else)
Coevolution: predator gets better, prey gets better, predator gets better...
- bats use sound to find moths (echolocation)
- moths evolve to hear the sounds, evade
- bats change the frequency
- moths evolve to create their own sounds, blocking the bats
- bats evolve to listen for the moth sounds
Parasitism: One lives off of energy and nutrients from the host "it is bad manners for the parasite to kill the host"
Mutualism: both benefit (birds eating bugs on cattle)
Commensalism: one benefits, the other does not care (orchids in trees)
Ecological succession:
Primary succession: from bare rock, no organic materials
Secondary succession: building blocks for live are there, have been removed (e.g. forest fire)
Resistance: "ecological intertia or persistence"
Resilience: ability to recover
Ecosystems have one or the other, not both:
Tropical rain forest: high diversity, high resistance, but when cleared cannot recover
Grasslands: low diversity, low resistance, but high resilience, organics are in the roots in a fire
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