Gradualism
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Gradualism suggests that change is gradual with the accumulation of unique morphological adaptation. Punctuated Equilibrium suggests that rapid change occurs, with a new species “erupting” from the ancestral lineage and then staying the same thereafter.
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Gradualism suggests that change is gradual with the accumulation of unique morphological adaptation. Punctuated Equilibrium suggests that rapid change occurs, with a new species “erupting” from the ancestral lineage and then staying the same thereafter. - PowerPoint PPT Presentation
Transcript of Gradualism
Gradualism suggests that change is gradual with the accumulation of unique morphological adaptation.
Punctuated Equilibrium suggests that rapid change occurs, with a new species “erupting” from the ancestral lineage and then staying the same
thereafter.
Gra
du
alis
m The evolution of new species by gradual accumulation
of small genetic changes over long periods of time
Slow and steady change in an organism
Over a short period of time it is hard to notice
Gra
du
alis
m Current living zebras (top), extinct quaggas (bottom)
Gra
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Gra
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Pu
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qu
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m Stable periods of no change (genetic equilibrium)
interrupted by rapid changes involving many different lines of descent
Rare, rapid events of branching speciation
Pu
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uat
ed E
qu
ilib
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m Horseshoe crabs have changed little
since their first appearance in the fossil record.
They are in a state of equilibrium
Pu
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ed E
qu
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riu
m
Pu
nct
uat
ed E
qu
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riu
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Pu
nct
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ed E
qu
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riu
m
Gra
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m
vs
Pu
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uat
ed
Similar to gradualism
Similar to punctuated evolution
