a) What is natural selection? b) Discuss three examples of natural selection in action.

a)  What  is  natural  selection? (Theory  put  forward  by  Charles  Darwin  that  explains  that)  Nature  selects  for  individuals  that are  well  adapted  to  a  particular  environment;  and  against  those  that  are  less  adapted;  2  mks

 b)  Discuss  three  examples  of  natural  selection  in  action Melanic  forms  of  peppered  moths;  in  Europe,  there  are  two  forms  of  peppered  moths;  white and  black;  before  industrialization,  the  tree  trunks  were  white;  therefore  the  white  peppered moths  were  white;  hence  were  camouflaged;  the  black  varieties  were  easily  noticed  and  fed upon  by  predatory  birds;  the  white  form  therefore  reproduced  and  increased  in  number; during  industrialization,  the  smoke  from  industries  coated  tree  trunks  black;  the  black  variety became  camouflaged;  reproduced  and  increased  in  population;  the  white  variety  were  easily noticed  and  fed  upon  by  predators;  they  reduced  in  population;  Resistance  against  drugs  and antibiotics;  where  microorganisms  are  continually  exposed  to  a  certain  drug;  their  cells synthesise  specific  proteins;  which  counter  the  drug;  this  ability  to  synthesize  the  protein  is passed  onto  the  offspring;  Resistance  to  pesticides  by  insects;  insects  such  as  mosquitoes when  continually  exposed  to  a  particular  pesticide;  synthesize  a  specific  protein  which  make them  resistant  to  the  pesticide;  this  is  then  inherited  by  their  offspring;  Max.  18  mks

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