Transcript Slide 1 - bYTEBoss

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