The History of Evolution Darwin Lamarck Cuvier

Species lion tiger liger Species: group of organisms that can interbreed and produce fertile offspring Different species rarely breed Interspecies breeding often results in sterile offspring Ex: Horse x Donkey = Mule Ex: Lion x Tiger = Liger When new species? no longer able to reproduce sucessfully tiger liger

horse donkey mule

Jean Baptiste de Lamarck Acquired Inheritance: Early theory where organisms could acquire traits after birth Problem: Traits acquired after fertilization cannot be passed to offspring Example: Giraffes & Long Necks Long necks are result of stretching to reach leaves Extra length was passed on to offspring

Geologic Change Early belief: Earth ~6,000 years old Life remained unchanged “New” Observations Rock layers (strata) contained differing fossils Deeper fossils less complex Environments changes as continents drift Uniformitarianism: geologic processes that shape earth are uniform

Charles Darwin Observed: Organisms vary based upon their environment Similarities between extinct fossils & modern life Marine fossils atop mountains Natural Selection: Process where organisms with favorable traits survive and reproduce Major concept in biology published in The Origin of Species (1859)

Adaptation & Variation Variation: Inherited traits that make an individual different from others Green, flat wings of the insect above Adaptation: Variation increases the chance of survival Ability to blend with environment

Butterflies won't lay eggs on plants with fake egg spots

Can you find the geckos?

Gross....bird poop...or is it???

Review When are two organisms considered a different species? Even though incorrect, why is Lamarck’s theory still relevant? How can the general age of rocks (and fossils) be determined? How does a variation and adaptation differ? What is natural selection?