1. Final Exam Review: Genetics & Evolution

2. OFFSPRING ARE CREATED EITHER SEXUALLY OR ASEXUALLY.
Asexual reproduction requires only 1 parent. Organisms that reproduce this way will create offspring that have DNA identical to that parent.
Sexual reproduction requires 2 parents and creates offspring that are different from the parents who created them. This is because the traits they inherit are a combination of both parents. Sexual reproduction creates offspring that are unique (different from their parents.)

3. Punnett Squares
Punnett squares allow us to predict what traits an offspring might inherit.
Punnett squares predict the possible genotypes of the offspring.
Genotype is the 2 genes an offspring inherits for a particular trait.
Genotypes can be:
Pure or homozygous (TT or tt)
Hybrid or heterozygous (Tt)

4. Cross a heterozygous brown haired parent with a homozygous blond parent
B= brown
b= blonde
Bb x bb B b Bb bb b
brown
blond Bb bb
brown
blond
50%
WHAT % OF THE OFFSPRING COULD HAVE BLOND HAIR?

5. Phenotypes
Phenotype is what trait is expressed from a certain genotype.
In other words, what you see.
Example: If T represents tall, the genotype TT or Tt will have the phenotype tall.
Only the pure recessive genotype tt will create the phenotype short.

6. Incomplete Dominance
When neither gene dominates the other, the trait is inherited by incomplete dominance.
The genotype of the offspring will be a blend of the 2 traits.
Example: Red flowers and white flowers show incomplete dominance. Red flowers would have the genotype RR and white would have WW. A blend between white and red would be RW or pink.

7. EVOLUTION
Evolution is a change in a species over time (usually a great deal of time).
Genetic variations (adaptations) occur over time.
If these variations are favorable to the organism, the organism will survive to reproduce. Its offspring will inherit that variation.
The organism will create stronger, better adapted offspring and the species will continue to survive.
This called survival of the fittest or natural selection.

8. Natural Selection
In order for natural selection to happen several things must be in place:
Overpopulation (too many organisms born than can survive)
Competition for the resources needed for survival
Survival of the fittest where the favorable variation survives.
These adaptations are passed on to the offspring through the inheritance of genes. When an organism acquires a trait (example: loses a limb, gets a scar, etc.) the offspring will NOT inherit that trait.