1. 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

2. 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

3. 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

4. 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

5. 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)

6. 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.

7. 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.

8. 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.

9. 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

10. 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.

11. 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.

12. 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