120 likes | 369 Views
The History of Evolution. Darwin. Lamarck. Cuvier. lion. Species. Species : group of organisms that can interbreed and produce fertile offspring Different species rarely breed Interspecies (between different species) breeding often results in sterile offspring Ex: Horse x Donkey = Mule
E N D
The History of Evolution Darwin Lamarck Cuvier
lion Species • Species: group of organisms that can interbreed and produce fertile offspring • Different species rarely breed • Interspecies (between different species) breeding often results in sterile offspring • Ex: Horse x Donkey = Mule • Ex: Lion x Tiger = Liger • When new species? No longer able to reproduce successfully tiger liger
horse donkey mule
Jean Baptiste de Lamarck • Acquired Inheritance: Early idea where organisms could acquire and pass on traits after birth. • Early Belief: Giraffes got long neck by stretching • Problem: Traits acquired after fertilization cannot be passed to offspring.
Geologic Change • Early belief: • Earth ~6,000 years old • Rejected by Buffon & Lyell • Life remained unchanged • “New” Observations • Rock layers (strata) contained differing fossils • Deeper fossils (older) less complex • Environments changes as continents drift • Environmental changes thought to affect characteristics of organisms • Uniformitarianism: geologic processes that shape earth are uniform and constantly happening
Charles Darwin • Observed: • Organisms have variations based upon 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)
Finches are another example. • Finches with strong, thick beaks live in areas with a lot of large, hard shell nuts. • Finches with delicate beaks live in areas where small insects and fruits are readily available.
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 Adaptation & Variation
Butterflies won't lay eggs on plants with fake egg spots
Can you find the geckos?
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 observations did Darwin make regarding the Galapagos’ tortoises and their environment? • What is natural selection?