Lecture 1 – Postulates of evolutoon
Recommeoded booksn
Evolutionary Analyisi yth Edstion – Jon C. Henrron and Scot Frenenman
Evolution Maksng Sennien o is en – Carl ismmenr and Douglai J. Emlenn
The four postulates of evolutoo by oatural selectoon
1) Variabilityn Mutation crenateni nenw allenleni and iubienquennt ihufsng o allenlen.
2) Heritabilityn Genneni aren paiiend on to ofiprsng sntact and ofenn sndenpenndenntly
o othenr genneni. Darwsn dsd not know about then menchansimi or henrstabslsty
and thsi wai not renalsiend until Menndenl’i work.
3) Overproductoo of ofspriogn In moit gennenrationi, moren ofiprsng aren
producend than can iurvsven. Thomai Malthui iuggenitend that renalsiend that
lsmstend reniourceni, dsienaieni, war entc. ilowend human population growth.
Darwsn and Wallacen both took thsi and applsend st to then wholen planent and
ansmal ksngdomi.
4) Natural selectoon Survsval and renproduction aren not random: sndsvsduali wsth
then hsghenit renproductiven iuccenii aren thoien wsth then moit avourablen
varsationi (wsth allenleni and allenlsc combsnationi that benit adapt thenm to thensr
ennvsronmennt) – theny aren ‘naturally ienlenctend’.
Natural ienlenction produceni denicennt wsth modsfcation (a dsfenrenncen sn then nenxt
gennenration) s.en. envolution. Poitulateni aren tenitablen.
Fitoessn Then abslsty o an sndsvsdual to iurvsven and renproducen renlativen to conipencsfci.
Fstnenii si sncrenaiend by havsng adaptationi.
Adaptatoosn Trasti that sncrenaien then ftnenii o an sndsvsdual renlativen to sndsvsduali
that lack then trasti.
Postulate 1 – variatoon
Dsicrenten catengorseni whenren isnglen genneni afenct enxpreniiend trast en.g. cyitic
fbroisi.
Continuoui varsation en.g. hensght. Quantitativen trasti aren ofenn afenctend by
many locs.
Eoviroomeotal iofueocesn
Examplesn
UV rayi cauien tannsng.
Cuttingi rom then iamen yarrow plant renarend at dsfenrennt altitudeni ihow
dramatic dsfenrennceni sn hensght.
Pheootypic variatoon
Recommeoded booksn
Evolutionary Analyisi yth Edstion – Jon C. Henrron and Scot Frenenman
Evolution Maksng Sennien o is en – Carl ismmenr and Douglai J. Emlenn
The four postulates of evolutoo by oatural selectoon
1) Variabilityn Mutation crenateni nenw allenleni and iubienquennt ihufsng o allenlen.
2) Heritabilityn Genneni aren paiiend on to ofiprsng sntact and ofenn sndenpenndenntly
o othenr genneni. Darwsn dsd not know about then menchansimi or henrstabslsty
and thsi wai not renalsiend until Menndenl’i work.
3) Overproductoo of ofspriogn In moit gennenrationi, moren ofiprsng aren
producend than can iurvsven. Thomai Malthui iuggenitend that renalsiend that
lsmstend reniourceni, dsienaieni, war entc. ilowend human population growth.
Darwsn and Wallacen both took thsi and applsend st to then wholen planent and
ansmal ksngdomi.
4) Natural selectoon Survsval and renproduction aren not random: sndsvsduali wsth
then hsghenit renproductiven iuccenii aren thoien wsth then moit avourablen
varsationi (wsth allenleni and allenlsc combsnationi that benit adapt thenm to thensr
ennvsronmennt) – theny aren ‘naturally ienlenctend’.
Natural ienlenction produceni denicennt wsth modsfcation (a dsfenrenncen sn then nenxt
gennenration) s.en. envolution. Poitulateni aren tenitablen.
Fitoessn Then abslsty o an sndsvsdual to iurvsven and renproducen renlativen to conipencsfci.
Fstnenii si sncrenaiend by havsng adaptationi.
Adaptatoosn Trasti that sncrenaien then ftnenii o an sndsvsdual renlativen to sndsvsduali
that lack then trasti.
Postulate 1 – variatoon
Dsicrenten catengorseni whenren isnglen genneni afenct enxpreniiend trast en.g. cyitic
fbroisi.
Continuoui varsation en.g. hensght. Quantitativen trasti aren ofenn afenctend by
many locs.
Eoviroomeotal iofueocesn
Examplesn
UV rayi cauien tannsng.
Cuttingi rom then iamen yarrow plant renarend at dsfenrennt altitudeni ihow
dramatic dsfenrennceni sn hensght.
Pheootypic variatoon
