D ARWIN ’ S C ASE F OR E VOLUTION

S TRUGGLE FOR EXISTENCE High birth rates and shortage of life’s needs Food and living space Fitness – ability to survive and reproduce in your environment Survival of the fittest

A DAPTATION Characteristic to increase fitness Successful adaptations allow one to be better able to survive and reproduce inheritable

E VIDENCE FOR E VOLUTION Darwin argued that living things have been evolving on Earth for millions of years. Evidence for this process could be found in the fossil record, the geographical distribution of living species, homologous structures of living organisms, and similarities in early development.

P ALEONTOLOGY Study of the fossil record as a picture of life’s changes Comparison of the different layers of rock Darwin learned through his studies that fossils formed in different layers of rock were evidence of gradual change over time. Different layers even provided evidence of how a specific species changed over time.

F OSSIL E VIDENCE PHYSICAL REMAINS 45 second movie

B IOGEOGRAPHY The distribution of animals and plants in an area

Under different pressures, once similar organisms could wind up different over long periods of time and many generations. Beaver NORTH AMERICA Muskrat Capybara SOUTH AMERICA Coypu Beaver Muskrat Beaver and Muskrat Coypu Capybara Coypu and Capybara

Pinta Island Intermediate shell Pinta Isabela Island Dome-shaped shell Hood Island Saddle-backed shell Hood Floreana Santa Fe Santa Cruz James Marchena Fernandina Isabela Tower G IANT T ORTOISES OF THE G ALÁPAGOS I SLANDS DRY LANDSCAPE LUSH Vegetation

M ORPHOLOGY Study of the form and structure of living organisms Some organs are present in many organisms with similarities

Turtle Alligator Bird Mammals Typical primitive fish 4. H OMOLOGOUS B ODY S TRUCTURES COMMON GENES Structures which have different mature forms but develop from similar embryonic tissues

M ORPHOLOGY Homologous structures Characteristics which are shared by related species Different mature structure, but similar in development Evidence of a common ancestor, and descent with modification

V ESTIGIAL O RGANS Organs that are remnants of earlier stages in life Example: Human appendix

E MBRYOLOGY Comparing development, especially vertebrates (animals with backbones) Similar development  common ancestor

S IMILAR EMBRYONIC DEVELOPMENT * EARLY STAGES OF DEVELOPMENT, CHICKENS, TURTLES, AND RATS LOOK SIMILAR * SHARE A COMMON ANCESTRY ( AND COMMON DEVELOPMENTAL GENES )

G UESS THE E MBRYO : HTTP :// WWW. PBS. ORG / WGBH / NOVA / EVOLUTION / GUESS - EMBRYO. HTML Click Launch Interactive and work through the program