Objective: Understand the Key Events in Darwin’s Life Do Now: 1. What characteristics made Darwin especially well suited for science? 2. What did Darwin see and do on his five-year voyage aboard the Beagle? 3. Why was the publication of On the Origin of Species a courageous act? Charles Darwin 1809 - 1882

Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits Charles Darwin 1809 - 1882

Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits 1. Variation Organisms of the same species are very similar. But they do have individual differences among traits, or variations. Variation is due to genetic differences among individuals from the same group

What Is the Source of Variation? Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits What Is the Source of Variation? Group the following processes as “source of variation” or “not source of variation”. Mitosis Meiosis Crossing over Cloning Sexual reproduction Mutations Replication Fertilization Meiotic cell division Mitotic cell division Asexual reproduction Different combination of genes Genetic recombination Fusion of eggs and sperm to produce zygotes Sorting and recombining of genes Source of Variation Not source of Variation

What Is the Source of Variation? Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits What Is the Source of Variation? Body cells Sex cells Harmful 99.999…% Beneficial 0.000…% Change in DNA Organism better adapted to environment Pass to offspring Mutations Random mistakes during replication Mutagens Radiation (Ultraviolet radiation, X-Rays Chemicals Causes More chances of surviving + New beneficial changes New species Exchange of DNA segments between non-sister chromatids Crossing over Meiosis gametes New combination of genes Independent assortment of chromosomes Random recombination of genes Sexual reproduction Egg (female) Combination of genes from two different individuals Fertilization + Zygote Sperm (male)

Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits 2. Overproduction Organisms produce more offspring than the environment can support. There is not enough food or living space for all of the offspring.

3. Struggle to Survive or Competition Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits 3. Struggle to Survive or Competition Overproduction leads to a struggle. All the organisms compete for food, water, and the other necessities of life. Only those organisms that are well suited to their surroundings survive and reproduce. The rest die.

Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits 4. Survival of the Fit Organisms with traits that make them well adapted, or suited to the environment, survive and reproduce. Darwin used the term natural selection to describe the survival of organisms with favorable traits.

5. Differential Reproduction Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits 5. Differential Reproduction These organisms which survived, they reproduced and passed on the favorable variation to the next generation

6. Accumulation of Traits Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits 6. Accumulation of Traits After many generations, the favorable trait accumulates in the population. This evolution process is known as natural selection.

Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits DO NOW: Describe the pictures. Do you agree or disagree with the vignettes? Explain.

Objective: Understand How the Mechanism of Natural Selection Explains Evolution Key Words: Genetic Variation, Competition, Overproduction, Survival of the Fit, Differential Reproduction, Accumulation of Traits