Wednesday, October 15, 2014

Coexistence of Similar Species

Thought

Again trying to force in the theory of evolution by finding 'excuses' for the coexistence of similar species, like what was done with presence of different species.

Digest

  • Communities support a variety of species performing apparently rather similar roles
  • Antarctic seals have undergone radiative evolution
    • Weddell seal:
      • feeds primarily on fish
      • has unspecialized dentition
    • Crab-eater seal:
      • feeds almost exclusively on krill
      • its teeth are suited to filtering these from the sea water
    • Ross seal:
      • feeds mainly on pelagic squid
      • has small, sharp teeth 
    • Leopard seal:
      • feeds on a wide variety of foods, including other seals and, in some seasons, penguins
      • has large, cusped, grasping teeth
  • Apparently very similar coexisting species may differ in subtle ways:
    • morphology
    • physiology
    • responses to their environment
    • role they play within the community of which they are part
  • The ecological niches of such species are said to be differentiated from one another
Weddell seal
Weddell seal

Question

I don't buy it, the idea of explaining the evolution of similar species to be a result of granular differences within the same geographical environment.