Evolution and Natural Selection By: Mr. Kauffman

Outline Evolution Early Ideas Charles Darwin Darwin’s Observations Darwin’s Finches Natural Selection Factors That Lead To Evolution Evidence Of Evolution What If You Don’t Evolve Threatened vs. Endangered vs. Extinct Causes Of Extinction

Evolution Evolution: change in inherited characteristics of a species over time What does that mean? A living thing develops new traits that can be passed from parents to their offspring Takes a very long time What is a species? A group of organisms with similar characteristics and the ability to produce offspring Example: golden retrievers and german shepherds are the same species (dog) Non-example: dogs and cats are different species

What are 3 similarities and 3 differences you see within this species?

Early Ideas Theory of Acquired Characteristics 1809 – idea developed by Jean Baptiste de Lamarck Said that organisms can develop characteristics during their lives and pass those characteristics on to their offspring Example: giraffes grew longer necks by stretching to reach food, then their babies were born with longer necks

Early Ideas Why was the Theory of Acquired Characteristics wrong? + ≠ Only genetic traits (DNA) can be passed on to offspring Traits developed during a lifetime can’t be passed on to offspring Proof: parents who build up a lot of muscle by working out won’t have really strong babies + ≠

Charles Darwin A British naturalist who sailed around the world in 1831 Explored the Galapagos Islands 20 isolated islands 600 miles off the coast of South America

Darwin’s Voyage

Galapagos Islands

Darwin’s Observations Observed many unique organisms on the Galapagos Islands He noticed that the organisms on the Islands looked similar to the ones from South America Darwin stated that the organisms on the Galapagos Islands must have evolved from the ones from South America Some organisms traveled to the Islands They then got stuck on the Islands Eventually they developed new characteristics to survive on the Islands

Galapagos Islands

Galapagos Wildlife

Galapagos Tortoises

Galapagos Tortoises 15

Darwin’s Finches Darwin found 13 different species of finches (birds) All are virtually identical except for: Beak size and shape Food they eat All 13 also looked very similar to 1 species found on South America Darwin stated that the 13 different species on the Galapagos Islands all evolved from the 1 species on South America

Galapagos Finches

Galapagos Finches

Natural Selection Darwin’s theory for how organisms evolve is called Natural Selection Based on his observations from the Galapagos Islands What does the theory of Natural Selection mean? Organisms with traits well suited to an environment are more likely to survive and pass on those traits to their offspring

Natural Selection What is the key determining factor in natural selection? Environment Organisms must adapt to their environment in order to survive Good adaptations: Poisons/toxins Camouflage Thick fur Ability to conserve water

What Traits Would Be Beneficial? 1.

What Traits Would Be Beneficial? 2.

What Traits Would Be Beneficial? 3.

Natural Selection Adaptation: any variation in an organism that makes it better suited to survive in its environment The variations are caused by mutations in DNA Mutations are random mistakes in DNA Most have no effect = organism stays the same Some can be harmful = organism dies quickly Some can be beneficial = organism has better chances to survive

Mutations