Habitat selection - PowerPoint PPT Presentation

1 / 14
About This Presentation
Title:

Habitat selection

Description:

Arctic tern. The evolution of habitat selection: The Least tern ... Allows a population to 'explore the fitness surface. Habitat selection: the Lesser tern ... – PowerPoint PPT presentation

Number of Views:667
Avg rating:3.0/5.0
Slides: 15
Provided by: Kevin6
Category:

less

Transcript and Presenter's Notes

Title: Habitat selection


1
Habitat selection
2
Habitat selection
3
Habitat selection
4
Habitat selection
5
Habitat selection
6
Habitat selection
7
Hive location as a group decision process
  • Hive selection is a balance between spacing and
    site quality
  • Spacing force dependent on resource scarcity
    (northern vs. southern)
  • Site quality force dependent on cavity and
    opening dimensions

8
  • Habitat selection sex specific disruption in
    beldings ground squirrel
  • Key points here are
  • Resource defense
  • Competitive release
  • Avoidance of in-breading depression

9
The effect of in-breading on reproductive success
Differential dispersion insures out-breading
10
Migration how could it have evolved?
Arctic tern
11
The evolution of habitat selection The Least
tern
12
  • Adaptive landscapes Evolving from one state to
    another
  • Sewall Wright developed the concept of the
    adaptive landscape as a means to describe changes
    in fitness resulting from changing evolutionary
    pressures over evolutionary time.
  • This is a heuristic that characterizes the
    complex summation of evolutionary forces.
  • Can be used to describe population-level changes
    in gene/allele distributions for polygenetic
    traits as a function in there changing fitness
    values
  • Can be used to describe the ecological forces
    (that act on gene/allele distributions for
    polygenetic traits) on phenotypes
  • Concepts
  • Directional selection The systematic culling of
    a population from one side of a distribution and
    survival of the portion of a population on
    another.
  • Stable Equilibrium a set of traits existing in a
    population over evolutionary time because changes
    in those traits are detrimental.
  • Unstable Equilibrium a condition where one or
    multiple selective pressures emerge and enhance
    the likelihood of divergence (speciation).
  • Local optimum a region of the landscape that is
    adaptive and isolated from other adaptive peaks.
  • Genetic Drift under conditions of no selective
    pressure random mutations change
    genotypes/phenotypes in random directions. Allows
    a population to explore the fitness surface

13
(No Transcript)
14
Habitat selection the Lesser tern
Write a Comment
User Comments (0)
About PowerShow.com