1. intraspecific: same species
Competition: the active demand for a limiting resource
shared by two or more individuals or species
intraspecific: same species
interspecific: different species
Competition does NOT occur in just sharing a resource
that is not limiting.
interference competition: direct sharing, physical contact
exploitative competition: indirect sharing, no physical contact
scramble competition: effects of competition equal to all
contest competition: effects greater in some than others
Ultimate effect is decreased reproductive output, lower fitness

3. Fig (EFB)
Effects on mass

4. Fig. 11.7
Effects on fecundity

5. Asymmetric
competition

6. Avoiding Intraspecific Competition Dispersal
Movement away from natal environment
--allows individuals to reach maximum growth
potential, little or no intraspecific
competition
--how a species with growing populations
expands its range to new areas

7. Costs Associated with Dispersal
1. greater risks, higher mortality
--naïve
--unfamiliar habitat, cover
--where to find food
2. low birth rates (fecundity), at first
costs balanced with benefits
--selection by fitness levels of dispersers
vs. non-dispersers

8. Helping Behavior in Birds
young remain in natal territory for
one or more years
become ‘helpers’ at parent’s new nest
gain experience at raising offspring
increase survivorship for breeding
> 220 spp. of birds have helpers

9. Avoiding Intraspecific Competition Dispersal 2. Territoriality
Active defense of a resource or space by an individual
or group of individuals

10. Carolina Wren Some territories can be all inclusive, held year-round,
to provide food, shelter, nesting space
Carolina Wren