APES Inter-Species Competition & Niche Overlap - Shope

(See worksheet.)

• results…
o competitive exclusion… one species must:
- migrate
- change (feeding or behavior)
- decline in population
- become extinct
o resource partitioning

• two types of competition
o interference
- one species limits resources access to other species
- territorialist
o exploitive
- one species is better at using a resource

• partitioning
o difference species use different parts of a resource
o ex.: birds in a tree

• variations in population
o stabilizing selection
- ex.: birds feed on largest and smallest spiders… thus stabilizing that population
o directional selection
- small-billed woodpeckers die off because their beaks are too short to reach
o disruptive selection
- “diversifying”
- selection against the average
- takes out middle values
- ex.: one hump to two humps (one high, one low)