Introduction to Theory of Evolution

• 1. Chapter 25: EvolutionBiology: Mrs. Neistadt

2. Changes Over Time: *Most species change over time. Thisslow, gradual change is calledEvolution____________________. Evidence shows the first living creatureswere single-celled organisms living in theoceans 3 billion years ago. *Many species have become extinct.Extinct species were once living, but nolonger exist. 3. Jean Baptist Lamarck In the 1800s scientists were studying anddiscovering __Fossils . A fossil is the remains of an organism thatlived long ago. Jean Baptist Lamarck proposed one of thefirst theories of evolution. He thought organisms developed traits byusing or not using parts of their body. Example: Giraffes Incorrect! 4. Charles Darwin In 1831 an Englishman named Charles Darwin tooka trip on the HMS Beagle. He was to map the coast of South America. He stopped on the Galapagos Islands where hebegan a study that would turn scientific study in anew direction. Darwin discovered the various Galapagos Islandshad different species of animals. He noticed 13 species of finches. Each finch had adifferent beak, specialized to find food on itsisland. 5. Charles Darwin Charles Darwin spend 20 years thinkingabout his discoveries. *In 1859, Darwin wrote the book, TheOrigin of Species to explain his theorieson evolution. 6. *Four Points to Darwins Theory:*Overproduction *Competition *Variations or Adaptations *Survival of the Fittest 7. Charles Darwin 8. Genetic Variations: Darwin did not know HOW genetic traitswere passed on. *A gene pool is the combined geneticinformation of all members of apopulation. By studying the gene pool of apopulation, scientists can see howvariations in traits are passed to offspring. 9. *Events That Can CauseEvolution:*NaturalSelection*Evolution can only occur when *Mutation an event causeschanges in thegene pool.*Genetic Drift 10. Natural Selection *Natural Selection is the way thatorganisms best suited to an environmentsurvive 11. Mutation *Mutation: If a mutation is harmful theorganism may die before passing on thegene. If the mutation is helpful, theorganisms live and pass the gene on. 12. Genetic Drift Genetic Drift is changes within a gene poolthat occurs due to random events, orwhen individuals leave or join thepopulation. 13. 3 Types of Evolution:DivergentConvergentCoevolutionEvolution EvolutionDifferentTypes ofEvolution 14. Your turnCreate a graphic organizer to Compare the 3 types of evolution:DivergentConvergentCoevolutionUse Internet research and/or your textbook Pg398 to help you.