Evolution Charles Darwin In 1831 Darwin set sail

Evolution!

Charles Darwin • In 1831, Darwin set sail for a voyage around the world. • Makes hundreds of observations and collects evidence. • Comes up with hypothesis about the way life changes over time: Evolution.

Darwin’s Observations • Plants and animals are well suited to wherever they live. • Similar habitats separated by oceans had very different animals. • Collected fossils (preserved animal remains) that looked like living creatures. • Galapagos Islands.

Evidence of Evolution #1: Natural Selection • Survival of the fittest: Strongest and best survive. • Organisms compete for resources. • Key factor is how well organism is suited for its environment: Like having fur or a beak that can crush seeds. • Fur would be an adaptation, which is an inherited characteristic that increases a organisms chance for survival.

• The birds look the same, but have different beaks. Why?

• What adaptations make this polar best suited to her environment?

Evidence of Evolution #2: Fossil Record • Fossils are remains of ancient life. • Different layers of rock formed at different times during Earth’s history. • By comparing older fossils to newer fossils, gradual change over time can be seen.

Evidence of Evolution #3: Geographic Distribution • Similar animals in different locations. • Came from common ancestor.

Evidence of Evolution #4: Homologous Body Structures • Structures that have different mature (fully grown) forms but develop from the same embryonic tissues are said to be Homologous Body Structures.

Evidence of Evolution #5: Similarities in Embryology • Early stages, or embryos, of many animals with backbones are similar.

Terminology • Natural Selection – Nature picks who lives and who dies. The strongest or most fit survive. • Artificial Selection – We pick who survives. • Adaptation – Inherited characteristic that increased chance for survival.