Evolution by Natural Selection

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Evolution by Natural Selection. No Genetic Change Through Time (no evolution). Scientists believed that all organisms were exactly how they have always been. Then Lamarck came to town. Jean Baptiste Lamarck French biologist Explained evolution! Wrong  Acquired Traits. - PowerPoint PPT Presentation

Text of Evolution by Natural Selection

Natural Selection

Evolution byNatural Selection

1No Genetic Change Through Time (no evolution)Scientists believed that all organisms were exactly how they have always been.

Then Lamarck came to townJean Baptiste LamarckFrench biologist

Explained evolution! Wrong

Acquired Traits.

Artistic ability, Math ability, etc.

Darwins LifeCharles DarwinWanted to be a doctorCouldnt stand the sight of blood

Married his cousin

Sea voyagesVoyage of BeagleNaturalist

On the HMS Beagle5 year journeyObserved flora/fauna everywhere he wentCataloguedComparedDeveloped his theory based on observations and evidence.Wrote several booksMost famous was On the Origin of Species

P.S. Mr. Chaneys Favorite Book by Darwin is . . . Drum roll please . . .

The Formation of Vegetable Mould Through the Action of Worms.

Darwins TheoryDescent with Modification.All species arise from pre-existing species

Generations pass, and species may change if the population has:

Genetic VariationAn Overproduction of offspringA Struggle to SurviveDifferential Reproduction*********Darwinian Fitness *********

So no one else figured this out until Darwin?!?!Who has greater Darwinian Fitness?

Evidence for Evolution: FossilsFossil RecordRocks form in layers

Organisms in deeper, older rock, are older

Different organisms lived at different times

Todays organisms are different from those of the past

Pennyslvanias State Fossil! The Trilobite

Example of Fossil that supports evolution

MegatheriumBig Birds


Fossils in adjacent layers are more alike than fossils from far apart layers

Evidence of Evolution: Transitional Species

Fossils of in-between organismsUsed as a timeline!Speaking of trilobites . . . . Heres a Pakicetus! (not a good transition!)Pakicetus14Vestigial Traits

Vestige- a mark, trace, or sign15Archaeopteryx

Bird? Or Reptile?Vestigial Traits

Diptera-Vestigial WingsSnake spursVestigial Wings in DrosophilaXanthopan morganii praedictaPredicted MothDarwin predicted its existence before it had been observed.Ridiculed by other scientistsOrchids have specific pollinators

Lets Process!1. How does the presence of vestigial traits support the theory of evolution by natural selection?

2. Why is variation necessary for natural selection to occur

3. If a natural disaster wiped out all the small seeds in an area with a population of birds with varying beak size, how might the population be affected?Darwinian Fitness

Who has GREATER fitness from the perspective of Darwin, and the theory of natural selection?