DARWIN’S CASE FOR EVOLUTION

STRUGGLE 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

ADAPTATION

Characteristic to increase fitness

Successful adaptations allow one to be better able to survive and reproduce inheritable

EVIDENCE FOR EVOLUTION

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.

PALEONTOLOGY 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.

FOSSIL EVIDENCE PHYSICAL REMAINS

http://darwiniana.org/horses.htm

45 second movie

BIOGEOGRAPHY

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 andMuskrat

Coypu

Capybara

Coypu andCapybara

Pinta IslandIntermediate shell

Pinta

Isabela IslandDome-shaped shell

Hood IslandSaddle-backed shellHoodFloreana

Santa Fe

Santa Cruz

James

Marchena

Fernandina

Isabela

Tower

GIANT TORTOISES OF THE GALÁPAGOS ISLANDS

DRY LANDSCAPE

LUSHVegetation

MORPHOLOGY

Study of the form and structure of living organisms

Some organs are present in many organisms with similarities

Turtle AlligatorBird Mammals

Typical primitive fish

4.  HOMOLOGOUS BODY STRUCTURESCOMMON GENES

Structures which have different mature forms but develop from similar embryonic tissues

MORPHOLOGY

Homologous structuresCharacteristics which are

shared by related speciesDifferent mature structure, but

similar in developmentEvidence of a common

ancestor, and descent with modification

VESTIGIAL ORGANS

Organs that are remnants of earlier stages in life

Example: Human appendix

EMBRYOLOGY

Comparing development, especially vertebrates (animals with backbones)

Similar development common ancestor

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

GUESS THE EMBRYO: HTTP://WWW.PBS.ORG/WGBH/NOVA/EVOLUTION/GUESS-EMBRYO.HTML

Click Launch Interactive and work through the program