Chapter 15.1/2 Notes Pg. 84 Section 1: Darwin’s Theory of Natural Selection Section 2: Evidence of Evolution E.Q. - Identify and explain how the evidences of evolution can be used To show common ancestry.

Darwin on the HMS Beagle Evolution  Darwin was hired as naturalist  His job was to collect biological and geological specimens during the ship’s travel. Chapter 15  Populations from the mainland changed after reaching the Galápagos.

The Galápagos Islands Evolution  Darwin began to collect finches and other animals on the four islands.  He noticed that the different islands seemed to have their own, slightly different varieties of animals Darwin’s Theory of Natural Selection Chapter 15

Darwin Continued His Studies Evolution  Darwin hypothesized that new species could appear gradually through small changes in ancestral species Darwin’s Theory of Natural Selection Chapter 15

Evolution  A process by which organisms with favorable variations reproduce at higher rates than those without such variations. Darwin proposes Natural Selection Chapter 15 In simple terms “ survival of the fittest”

The Origin of Species Evolution  Darwin published On the Origin of Species by Means of Natural Selection in Darwin’s Theory of Natural Selection Chapter 15

6 Evidences of Evolution 1.Fossil Record (biogeography) 2.Vestigial Structures 3.Homologous Structures 4.Analogous Structures 5.Embryology 6.Comparative Biochemistry* *also called macromolecules

15.2 Evidence of Evolution Evolution  The fossil record Glyptodont  Fossils provide a record of species that lived long ago.  Fossils show that ancient species share similarities with species that now live on Earth. Armadillo Chapter 15

Evolution Vestigial Structures  Structures that are in an organism that serve no known function. ex=appendix of humans 15.2 Evidence of Evolution Chapter 15  Vestigial structures might have been used by ancestors. Hind limb of a whale

15.2 Evidence of Evolution  Anatomically similar structures inherited from a common ancestor are called homologous structures.

Evolution  Analogous structures can be used for the same purpose and can be superficially similar in construction, but are not inherited from a common ancestor. ex: wings 15.2 Evidence of Evolution Chapter 15

Evolution  Vertebrate embryos exhibit homologous structures during certain phases of development but become totally different structures in the adult forms. Comparative Embryology 15.2 Evidence of Evolution Chapter 15

Evolution  Amino acids are used to show similarities.  Similar species = similar amino acid sequences Comparative Biochemistry (macromolecules) 15.2 Evidence of Evolution Chapter 15

Evolution  Derived traits are newly evolved features, such as feathers, that do not appear in the fossils of common ancestors.  Ancestral traits are more primitive features, such as teeth and tails, that do appear in ancestral forms. Derived vs. Ancestral traits Chapter 15

Evolution Types of Adaptation  An adaptation is a trait that increases an organism’s reproductive success. (a trait that helps it survive)  Fitness is a measure of the relative contribution an individual trait makes to the next generation. (how well does it survive/reproduce) 15.2 Evidence of Evolution Chapter 15 Webbed feet = adaptation

Evolution Camouflage  Allows organisms to become almost invisible to predators Leafy sea dragon Orchid Praying Mantis 15.2 Evidence of Evolution Chapter 15

Evolution Mimicry  One species evolves to resemble another species. Western coral snake California kingsnake 15.2 Evidence of Evolution Chapter 15

Notes REView ?’s Answer each with clear explanations. 1.What islands did Darwin stop at? What did he see? What idea did he propose? 2.Explain natural selection in your own words. (provide example) 3.List/describe all six different types of evidence used to show common ancestry. ** explain each and provide example of each 4. Explain what an adaptation is and give two human adaptations as examples.