Explain the different evidences of evolution. 20 marks

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Comparative anatomy / taxonomy;
  • Members of a phylum / group show similarities ; organisms have structures / organs performing the same function ; e.g. digestive system ; nervous system same function etc (any correct example 1mk)
  • The pentactyl limb / any correct example; these are called homologous organs / structures; homologous (same origin but have different function;  Analogous structures / different structures performing the same function e.g. wings of insects, bat and birds; Analogous – different origin but performing same function;

Fossil records / Paleontology; 
  • remains of organisms preserved in naturally occurring materials for many years; show morphological changes of organisms over a long period of time; e.g. skull of man ( leg of horse)
Comparative embryology; 

  • embryos of vertebrates have similar morphology; suggesting the organisms have a common origin / ancestry ;
Geographical distribution; 

  • continents present are thought to have been a large landmass; joined together; as a result of continental drift; isolation; occurred bringing about different patterns of evolution; e.g. Ilamas in the amazons resemble the camel / any other correct example e.g. kangaroo in Australia Jaguar in S. America; camel in Africa;
Comparative serology / physiology ; 

  • antigen – antibody reactions / RH factor/ blood groups / haemoglobin structure reveal some phylogenetic relationship among organisms  / common ancestry.

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