EVOLUTION, DARWINNatural Selection

S.W.B.A.T.: Determine that what Darwin viewed in nature about the traits of living things helps organisms even today survive and adapt to their

surroundings.

What Did Darwin’s Travels Reveal

• The diversity of living species was far greater than anyone had previously known

• These observations led him to develop the Theory of Evolution

How did tortoises and birds differ among the islands of the

Galapagos?

• Each island

had its own type

of tortoises

and birds that

were clearly

different from

other islands

GALAPAGOSvideo of the island

Natural Selection

• The traits that help an organism survive in a particular environment are “selected” in natural selection

Evolution is when organisms change over time

So, modern organisms descended from ancient ones

Evidence of EvolutionReview

• Fossil Record provides evidence that living things have evolved

• Fossils show the history of life on earth and how different groups of organisms have changed over time

Primate Fossils

Primate Bone Structure

Primate Brain Capacity

Vestigial OrgansEvidence of Evolution

• Organ that serves no useful function

• Present day organisms evolved from ancestors in which these organs were useful

Biochemical Evidence• All living organisms are made of the same

20 common amino acids

• All living organisms have DNA as the code of life with the same 4 bases: adenine, thymine, cytosine, guanine

Homologous StructureEvidence of Evolution

• Body parts that are similar in structure in different organisms and seem to have developed from the zygote the same way

• Homologs may have different uses in different species

Similar EmbryosEvidence of Evolution

• In their early stages of development, chickens, turtles and rats look similar, providing evidence that they shared a common ancestry.

Natural Selection Videohttp://science.discovery.com/videos/100-greatest-discoveries-shorts-natural-selection.html

http://www.youtube.com/watch?v=vfmOaAz371M&NR=1&feature=endscreen

Origin of Species Video