Transcript Evidence for Evolution

Evidence for Evolution
by
Natural Selection
Hunting for
evolution clues…
Elementary, my
dear, Darwin!
Regents Biology
2006-2007
Evidence supporting evolution
 __________________________

change over time
 __________________________

comparing body structures
 homology & vestigial structures
 embryology & development
 ______________________

protein & DNA sequence
 ______________________

human caused evolution
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1. Fossil record
 __________________________________

new layers cover older ones
 creates a record over time

___________________________________
___________________________________
 over a long period of time
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Fossils tell a story…
the Earth is old
Life is old
Life on Earth has changed
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Evolution of birds
Today’s organisms
descended from
ancestral species
Fossil of Archaeopteryx
 lived about 150 mya
 links reptiles & birds
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We found the fossil — no joke!
Land Mammal
?
?
?
Complete series
of transitional
fossils
Someone’s idea of a joke!
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ButBiology
the joke’s
on them!!
Ocean Mammal
?
Evolution from sea to land
 2006 fossil discovery of early tetrapod

4 limbs
 Missing link from sea to land animals
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3. Anatomical record
Animals with different
structures on the surface
But when you look under
the skin…
It tells an evolutionary story
of common ancestors
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Compare the bones
 __________________________________

limbs that perform __________________
are built from the ___________________
How could these
very different animals
have the
same bones?
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Homologous structures
 ____________________________________
 homo- = same
 -logous = information
 Forelimbs of human, cats, whales, & bats

______________________________
 on the inside
______________________________
 ______________________________

 on the outside

______________________________
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But don’t be fooled by these…
 _________________________

look similar
 on the outside
same function
 different structure & development

How is a bird
like a bug?
 on the inside
different origin
 __________________________

Solving a similar problem with a similar solution
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Analogous structures
 Dolphins: aquatic mammal
 Fish: aquatic vertebrate
both adapted to
life in the sea
 not closely related

Watch the tail!
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Convergent evolution
 3 groups with wings

Does this mean they have a
recent common ancestor?
They just
came up
with the
sameNO!
answer!
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Flight evolved 3
separate times —
evolving similar
solutions to similar
“problems”
Convergent evolution led to mimicry
 Why do these pairs look so similar?
Monarch male
Viceroy male
poisonous
edible
Which is the moth
vs.
the
bee?
fly vs. the bee?
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fly
bee
moth
bee
Vestigial organs
 Hind leg bones on whale fossils
Why would whales
have pelvis & leg
bones if they were
always sea creatures?
Because they
used to
walk on land!
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Comparative embryology
 Development of embryo tells an
evolutionary story

similar structures during development
all vertebrate embryos have a “gill
pouch” at one stage of development
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3. Molecular record
 Comparing DNA & protein structure

everyone uses the same genetic code!
 DNA
Human
Macaque
Dog Bird
Frog
Lamprey
8
32 45
67
125
 compare common genes
 compare common proteins
number of amino acids different
from human hemoglobin
0 10 20 30 40 50 60 70 80 90 100 110 120
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Building “family” trees
Closely related species are branches on the tree —
coming from a common ancestor
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4. Artificial selection
 How do we know natural selection can
change a population?
we can recreate a similar process
 __________________________________
“descendants” of wild mustard

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Selective Breeding
Humans create the
change over time
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“descendants”
of the wolf
Artificial Selection
…and the
examples
keep coming!
I liked
breeding
pigeons!
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Artificial Selection gone bad!
 Unexpected
consequences of
artificial selection
Antibiotic resistance
Antibiotic resistance
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Insecticide resistance
 Spray the field, but…

____________________
____________________
 _________________
____________________
____________________
 ____________________
 ____________________
____________________

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Any Questions??
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2006-2007