1. Mendel and Natural Selection

2. Mendel and Natural Selection
What do you think Natural Selection is?
Who is Gregor Mendel?
What is Asexual Reproduction?
What is Sexual Reproduction?

3. Mendel and His Peas Gregor Mendel
Gregor Mendel, born in 1822, is named the “Father of Genetics”.

4. Mendel and His Peas Gregor Mendel
Mendel began doing experiments with garden peas. He studied the shape of the seeds, how tall the plants grew to be, as well as the color of the flowers produced.

5. Mendel and His Peas Gregor Mendel
Mendel crossed flowers that were true-breeding for each characteristic.
He crossed a purple flowered plant with a white flowered plant.

6. Mendel and His Peas Gregor Mendel
Purple Parent
Gregor Mendel
He created a first-generation of plants that all had purple flowers.
Where did the white color go??
White Parent

7. Mendel and His Peas Gregor Mendel
Mendel noticed in the first generation, all of the white flowers seemed to disappear. He called this a recessive trait. The white color faded into the background at first. It then showed back up as he pollinated the flowers again.

8. Mendel and His Peas
Mendel took two of his four first generation purple flowered plants and crossed them together.
He then got three purple plants, and one white flowered plant.
Purple Parent
Purple Parent

9. Mendel and His Peas Gregor Mendel
The color (purple) that seemed to mask over the recessive color was named the dominant trait.

10. Mendel and His Peas Gregor Mendel
Mendel was responsible for figuring out that each plant carried two sets of instructions for each characteristic (one from the “mom” and one from the “dad”).
Like many scientists, his work was not accepted until after his death.

11. Let’s Review
- 1 -
1. If you crossed a true-breeding black rabbit with a true-breeding white rabbit, all of the offspring would be black. Which trait is dominant in rabbits: black fur or white fur?
2. Which trait is recessive?

12. Answer
Black Rabbit
The trait for black fur is dominant over the trait for white fur. The white fur trait is recessive.
White Rabbit

13. Mendel and His Peas
What Do You Think?
What is the difference between sexual reproduction and asexual reproduction?

14. Mendel and His Peas Sexual Reproduction Asexual Reproduction
Two parents needed
One parent needed
New organism shares traits of both parents.
New organism is an exact copy of parent.
Most multi-celled organism reproduce this way.
Most single-celled organism reproduce this way.

15. Let’s Review!
- 1 -
Which kind of reproduction results in offspring that are different from the parents- sexual or asexual reproduction?
Explain why.

16. Answer
Sexual reproduction results in offspring that are different from the parents. In sexual reproduction, two parent cells join together to form a new individual who has his or her own combination of genes.

17. Mendel and Natural Selection
Vocabulary
Heredity- the passing of traits from parent to offspring.
Self-pollinate- A plant is often able to pollinate by itself because it contains both the male and female reproductive structures. This only requires 1 parent.
True-breeding- all of the offspring will have the same trait as the parent when self-pollinated.

18. Mendel and Natural Selection
Vocabulary
First-generation- the very first set of offspring from two parents.
Dominant trait- the trait observed when at least one dominant allele for a characteristic is inherited.
Recessive trait- a trait that is apparent only when two recessive alleles for the same characteristic are inherited.

19. Mendel and Natural Selection
Vocabulary
Genes- a segment of DNA that carries hereditary instructions and is passed from parent to offspring.
Alleles- multiple forms of the same gene.
Genotype- an organisms inherited combination of alleles.
Phenotype- an organisms inherited appearance.

20. Mendel and Natural Selection
Websites!