Populations are the Units of Evolution

Individual organisms evolve during their lifetimes is one common misconception. defintion of population is a group of individuals of the same species living in the same place at the same time. Favored insects with alleles for pesticide resistance, these insects left more offspring, and the population changed or evolved is natural selection. Certain isolation is common for populations confined to widely seperated islands or in different lakes due to interbreeding and little exchange of genes between them. Biologist uses a gene pool in studying evolution at a population level. Gene pool is the total collection of genes in one population at any one time.

  
http://www.google.com/imgres?hl=en&client=firefox-a&hs=mNM&sa=X&tbo=d&rls=org.mozilla:en-US:official&biw=1440&bih=754&tbm=isch&tbnid=Wc7rEg-95q5azM:&imgrefurl=http://www.oldsaybrook.k12.ct.us/groups/scherberclass/wiki/cbef8/CP_BIOLOGY_CLASS_AND_LAB_20122013.html&docid=j7TQcmDNFa4rpM&imgurl=http://www.oldsaybrook.k12.ct.us/groups/scherberclass/wiki/f5dfb/images/2e56c.jpg&w=560&h=420&ei=i6a_UNipNYTe8ATXmoDgDQ&zoom=1&iact=hc&vpx=277&vpy=133&dur=386&hovh=165&hovw=220&tx=151&ty=124&sig=105512698409091355603&page=1&tbnh=135&tbnw=180&start=0&ndsp=32&ved=1t:429,r:2,s:0,i:93



 
http://www.google.com/imgres?hl=en&client=firefox-a&hs=mNM&sa=X&tbo=d&rls=org.mozilla:en-US:official&biw=1440&bih=754&tbm=isch&tbnid=nM7R0q3M3gM_0M:&imgrefurl=http://www.mansfield.ohio-state.edu/~sabedon/campbl22.htm&docid=gWB_orusLwxrYM&imgurl=http://www.mansfield.ohio-state.edu/~sabedon/campbl22_files/image003.jpg&w=304&h=103&ei=i6a_UNipNYTe8ATXmoDgDQ&zoom=1&iact=hc&vpx=205&vpy=193&dur=85&hovh=82&hovw=243&tx=152&ty=69&sig=105512698409091355603&page=3&tbnh=82&tbnw=243&start=70&ndsp=36&ved=1t:429,r:99,s:0,i:390