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Evidence for Evolution
Evidence Supporting EvolutionEvidence Supporting Evolution
Fossil recordFossil record• shows change over timeshows change over time
Anatomical recordAnatomical record• comparing body structurescomparing body structures
homology & vestigial structureshomology & vestigial structures embryology & developmentembryology & development
Molecular recordMolecular record• comparing protein & DNA sequencescomparing protein & DNA sequences
Artificial selectionArtificial selection• human caused evolutionhuman caused evolution
Fossil RecordFossil Record Layers of rock contain fossils Layers of rock contain fossils
• new layers cover older onesnew layers cover older ones creates a record over timecreates a record over time
• fossils show a series of organisms have lived fossils show a series of organisms have lived on Earth on Earth
over a long period of timeover a long period of time
Fossils Tell A StoryFossils Tell A Story
the Earth is oldthe Earth is old
Life is oldLife is old
Life on Earth has changedLife on Earth has changed
Fossil of Fossil of ArchaeopteryxArchaeopteryx lived about 150 myalived about 150 mya links reptiles & birdslinks reptiles & birds
Today’s organisms Today’s organisms descended from descended from
ancestral speciesancestral species
Today’s organisms Today’s organisms descended from descended from
ancestral speciesancestral species
Evolution of BirdsEvolution of Birds
Land Mammal
?
???
Where are the
intermediate
fossils?Where are the
intermediate
fossils?
Ocean Mammal
Someone’s idea of a joke!
But the joke’s on them!!
Complete seriesof transitional
fossils
We found the fossil — no joke!
Evolution from Sea to LandEvolution from Sea to Land 2006 fossil discovery of early tetrapod2006 fossil discovery of early tetrapod
• 4 limbs4 limbs Missing link from sea to land animalsMissing link from sea to land animals
Anatomical RecordAnatomical Record
On the outside, animals may look different. , But when you look under the skin…
It tells an evolutionary story of common ancestors
Anatomical RecordAnatomical Record
The same bones under the skinThe same bones under the skin• limbs that perform limbs that perform different functionsdifferent functions are built are built
from the from the same bonessame bones
How could these different
organisms have the same bones?
Homologous StructuresHomologous Structures Structures that come from the same Structures that come from the same
originorigin homo- = samehomo- = same -logous = information-logous = information
Forelimbs of human, cats, whales, & bats Forelimbs of human, cats, whales, & bats • same structuresame structure
on the insideon the inside
• same development in embryo same development in embryo • different functionsdifferent functions
on the outsideon the outside
• evidence of common ancestorevidence of common ancestor
But Don’t Be Fooled By These…But Don’t Be Fooled By These…
Analogous structuresAnalogous structures• look similarlook similar
on the outsideon the outside
• same functionsame function• different structure & developmentdifferent structure & development
on the insideon the inside
• different origindifferent origin• no evolutionary relationshipno evolutionary relationship
How is a bird like a bug?
Analogous StructuresAnalogous Structures Dolphins: Dolphins: aquatic mammalaquatic mammal Fish: Fish: aquatic vertebrateaquatic vertebrate
• both adapted to both adapted to life in the sealife in the sea
• not closely relatednot closely related
Watch the tail!
Convergent evolutionConvergent evolution 3 groups with wings3 groups with wings
• Does this mean they have a Does this mean they have a recent common ancestor?recent common ancestor?
Flight evolved 3 separate times — evolving similar solutions to similar “problems”
Flight evolved 3 separate times — evolving similar solutions to similar “problems”
NO!
They justcame up with the
same answer!
Convergent evolution led to Convergent evolution led to mimicrymimicry Why do these pairs look so similar?Why do these pairs look so similar?
Monarch malepoisonous
Viceroy maleedible
fly bee moth bee
Which is the fly vs. the bee?Which is the moth vs. the bee?
Vestigial organsVestigial organs
Hind leg bones on whale fossilsHind leg bones on whale fossils
Why would whales have pelvis & leg bones if they were always sea creatures?
Why would whales have pelvis & leg bones if they were always sea creatures?
Because they used to
walk on land!
Comparative embryologyComparative embryology Development of embryo tells an Development of embryo tells an
evolutionary story evolutionary story • similar structures during developmentsimilar structures during development
all vertebrate embryos have a “gill pouch” at one stage of development all vertebrate embryos have a “gill pouch” at one stage of development
3. Molecular record3. Molecular record
100 20 30 40 50 60 70 80 90 100 110 120
LampreyFrogBirdDogMacaqueHuman
328 45 67 125
Comparing DNA & protein structureComparing DNA & protein structure• everyone uses the same genetic code! everyone uses the same genetic code!
DNADNA
compare common genes compare common proteins
compare common genes compare common proteins
number of amino acids different from human hemoglobinnumber of amino acids different from human hemoglobin
Building “family” treesBuilding “family” treesClosely related species are branches on the tree — Closely related species are branches on the tree — coming from a common ancestorcoming from a common ancestorClosely related species are branches on the tree — Closely related species are branches on the tree — coming from a common ancestorcoming from a common ancestor
How do we know natural selection can How do we know natural selection can change a population?change a population?• we can recreate a similar processwe can recreate a similar process• ““evolution by human selection”evolution by human selection”
4. Artificial selection4. Artificial selection
“descendants” of wild mustard“descendants” of wild mustard
Selective BreedingSelective BreedingHumans create the change over timeHumans create the change over time
“descendants” of the wolf“descendants” of the wolf
Artificial Selection gone bad!Artificial Selection gone bad!
Unexpected Unexpected consequences of consequences of artificial selectionartificial selectionPesticide resistancePesticide resistance
Antibiotic resistanceAntibiotic resistance
Insecticide resistance Insecticide resistance
Spray the field, but…Spray the field, but…• insecticide didn’t insecticide didn’t
kill all individualskill all individuals variationvariation
• resistant survivors resistant survivors reproducereproduce
• resistance is inheritedresistance is inherited• insecticide becomes less & insecticide becomes less &
less effectiveless effective
Any Questions??Any Questions??
Niche Placental Mammals Australian Marsupials
BurrowerMole
Anteater
Mouse
Lemur
Flyingsquirrel
Ocelot
Wolf Tasmanian “wolf”
Tasmanian cat
Sugar glider
Spotted cuscus
Numbat
Marsupial mole
Marsupial mouse
Anteater
Nocturnalinsectivore
Climber
Glider
Stalkingpredator
Chasingpredator
Parallel EvolutionParallel Evolution
marsupial mammal
placental mammal
filling similar roles in nature, filling similar roles in nature, so have similar adaptationsso have similar adaptationsfilling similar roles in nature, filling similar roles in nature, so have similar adaptationsso have similar adaptations
not closely relatednot closely related
Vestigial organsVestigial organs Structures on modern animals that have no Structures on modern animals that have no
functionfunction• remains of structures that were functional in remains of structures that were functional in
ancestorsancestors
• evidence of change over timeevidence of change over time some snakes & whales have pelvis bones & leg some snakes & whales have pelvis bones & leg
bones of walking ancestorsbones of walking ancestors eyes on blind eyes on blind
cave fishcave fish human tail bonehuman tail bone