Changes Over Time: *Most species change over time. This slow, gradual change is called Evolution ____________________. Evidence shows the first living creatures were single-celled organisms living in the oceans 3 billion years ago. *Many species have become extinct. Extinct species were once living, but no longer exist.
Jean Baptist Lamarck In the 1800s scientists were studying and discovering __Fossils . A fossil is the remains of an organism that lived long ago. Jean Baptist Lamarck proposed one of the first theories of evolution. He thought organisms developed traits by using or not using parts of their body. Example: Giraffes Incorrect!
Charles Darwin In 1831 an Englishman named Charles Darwin took a trip on the HMS Beagle. He was to map the coast of South America. He stopped on the Galapagos Islands where he began a study that would turn scientific study in a new direction. Darwin discovered the various Galapagos Islands had different species of animals. He noticed 13 species of finches. Each finch had a different beak, specialized to find food on its island.
Charles Darwin Charles Darwin spend 20 years thinking about his discoveries. *In 1859, Darwin wrote the book, “The Origin of Species” to explain his theories on evolution.
*Four Points to Darwin’s Theory: *Overproduction *Competition *Variations or Adaptations *Survival of the Fittest
Genetic Variations: Darwin did not know HOW genetic traits were passed on. *A gene pool is the combined genetic information of all members of a population. By studying the gene pool of a population, scientists can see how variations in traits are passed to offspring.
*Events That Can CauseEvolution: *Natural Selection *Evolution can only occur when *Mutation an event causes changes in the gene pool.*Genetic Drift
Natural Selection *Natural Selection is the way that organisms best suited to an environment survive
Mutation *Mutation: If a mutation is harmful the organism may die before passing on the gene. If the mutation is helpful, the organisms live and pass the gene on.
Genetic Drift Genetic Drift is changes within a gene pool that occurs due to random events, or when individuals leave or join the population.
3 Types of Evolution: Divergent Convergent Coevolution Evolution Evolution Different Types of Evolution
Your turn…Create a graphic organizer to Compare the 3 types of evolution: Divergent Convergent Coevolution Use Internet research and/or your textbook Pg398 to help you.