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Types of selection

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Types of selection

  1. 1. Types of Selection<br />(Stabilizing, Directional, Disruptive)<br />
  2. 2. Natural Selection<br />Animals adapting to environment<br />Advantaged animals survive and reproduce<br />
  3. 3. Stabilizing Selection<br />Most Common<br />Average survives<br />
  4. 4. Stabilizing Selection<br />Examples:<br />Short flowers die: No sunlight<br />Medium flowers live: Perfect conditions<br />Tall Flowers die: Wind damage<br />Lightweight babies have higher mortality rate: weaker<br />Average weight babies survive more often: healthy<br />Heavyweight babies have higher mortality rate: when being born <br />
  5. 5. Directional Selection<br />One extreme trait is favoured<br />
  6. 6. Directional Selection<br />Examples…<br />A long time ago…<br />Short neck giraffes died: could not reach leaves on tree<br />Medium neck giraffes died: could not reach leaves on tree<br />Long neck giraffes prospered: leaves were reachable<br />A long time ago…<br />Small horses died: very disadvantageous<br />Medium horses died: disadvantageous<br />Large horses prospered: advantageous<br />
  7. 7. Disruptive Selection<br />Opposite extreme traits are favoured<br />Average trait is eliminated<br />
  8. 8. Disruptive Selection<br />Examples…<br />In an environment with black and white rocks…<br />White rabbit lives: Camouflaged<br />Grey rabbit dies: Seen by predator<br />Black rabbit lives: Camouflaged<br />In an environment with deep and shallow flowers…<br />Short beak hummingbird lives: can get pollen from flower<br />Medium beak hummingbird dies: cannot get pollen from flower<br />Long beak hummingbird lives: can get pollen from flower<br />
  9. 9. Video on Types of Selection<br />
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  11. 11. Works Cited<br />

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