EVOLUTION

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Evolutionary biology:-
Study life form on earth
Origin of earth:-
# found 4.5 billion year back
# earth surface covered by water vapour, methane,  carbon dioxide, ammonia
# radiation broke hydrogen and oxygen of water
# cooling waste leads rain and water bodies
Theories of origin of life:-
1) theory of special creation:-
Acc. This god created life
2) cosmozoic theory:-
Acc. This life comes from outer surface
3) theory of spontaneous generation:-
Life comes form decaying and rooting matter
4) theory of chemical evolution:-
By oparin & Haldane, stated life originated from pre-existing non-living organic molecule
Miller experiment:-
Closed flask containing CH4, H2, NH3 and waste vapor and electric discharge was created
,they found presence of amino acid after repeating this experiment many time
Evidence of evolution:-
1) paleontological evidence:-
Study of fossil called paleontology
2) morpological and conparitive anatomical evidence:-
Phylogenetic history can be revealed by comparative study of external and internal structure
Homologous organ:-
Organ have same structural design and origin but different function
Due to different need, some structure developed differently called divergent evolution
Analogous organ:-
organ which are anatomically different but functionally similar called analogous organ
Due to same function, different structure evolve similarity called convergent evolution
3) Biochemical evidence:-
Similarity in protein and gene
4) Biogeographical evidence:-
Species restricted to a region developed unique feature
Adaptive radiation:-
Different species starting from a common point in a geographical area radiate other geographical area
1) Darwin finches:-
Observed various variety of finches in same island
2) marsupial of Australia:-
Within Australian continent, many marsupial or pouched animal are seen
3) placental animal in Australia:-
Which appear similar to corresponding marsupial
THEORIES OF EVOLUTION
1) lamarck's theory:-
Acc. Lamarck, evolution of life form occurred due to use and disuse of lamarck
2) Darwin Theory:-
Adaptability is inherited and fitness is the end result of ability to adapt and get selected by nature
Two main keys of this natural selection :-
a) Industrial melanism:-
      White papermoth could be easily picked up by predator in dark sky, so they adapt dark color to match the environment and survived
b) chemical resistance :-
Excessive use of pesticide and insecticide resulted in resistance of microbes as in lesser time
3) mutation theory of evolution:-
Evolution is cause by sudden change in large diffrence in population
Hardy-Weinberg principle:-
Allelic frequencies in population are stable and remain constant from generation to generation
Factor affecting:-
1) gene migration
2) genetic drift
3) mutation
4) genetic recombination
5) natural selection
       a) stablisation
       b) directional change
       c) disruption