theory of evolution there is diversity in living things even within a species we don't all look...
TRANSCRIPT
Theory of Evolution There is diversity in living things even within
a species We don't all look alike We don't all behave alike
Those traits can be passed on from parent to offspring
Darwin didn't know how. Mendel did = Genes
There is a struggle to survive Many organism mass produce offspring and few
make it. There is high infant mortality for humans as well in
some places
Theory of Evolution Organisms that are best suited to their environment
have a survival advantage Doesn't necessarily mean the strongest At times it might be good to be small and quiet (early
mammals) Survival of the fittest
Those with a survival advantage will produce more offspring and pass their traits on to those offspring, thus the population will begin to have those particular traits
Natural selection Already known from "unnatural selection" breeding
techniques Large boar with large sow = large piglet.
Fundamental Genetics
In a classic experiment Mendel studied the inheritance of seed color. Dichotomous traits
peas can be brown or white True breeding lines
plants bred to produce only white or only brown peas
Bred white pea plants with a brown pea plants
offspring had all brown peas
Then he bred the offspring with one another 75% brown and 25% white
Implications we do not necessarily inherit the traits of our parents Traits can be passed on across generations
Phenotype Organisms observable traits
Genotype Genetic material that can be passed on
You may have Brown hair and so might your spouse Brown hair phenotype
But it is possible to have a red haired child Red hair Genotype
Mendelian theory
1) There are two kinds of inherited factors for each dichotomous trait For Seed color
A brown seed factor controls brown A white seed factor controls white
Now we call these factors genes
2) Each organism has two genes for each of its dichotomous traits
Each pea plant has either Two brown seed genes Two white seed genes Or one of each
These pairs of genes that control the same trait are called alleles
Homozygous two identical genes for a trait
Heterozygous two different genes for a trait
Dominant vs Recessive Genes
3) One of the two kinds of genes for each trait dominates the other in heterozygous organisms Brown seed is dominant over white
seed if heterozygous it will have brown seeds The only way to have white seeds is to be
homozygous for white seeds
4) Each organism randomly inherits one of it’s father’s two genes and one of it’s mother’s two genes.