Bio Lec 1: Evolution

Front 1

Three key observations about life:

Back 1

Organisms suited to their environments

Shared characteristics (unity)

Rich diversity

Front 2

Natural selection depends of the :

Back 2

differential success, in terms of surviving and reproducing, of variants

Front 3

Species -

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a group of individuals that can exchange genetic material through interbreeding, or share alleles through reproduction.

Front 4

Gene pool -

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all the alleles present in all individuals in a species.

Front 5

Populations -

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an interbreeding group of organisms of the same species living in the same geographical area

Front 6

what is Mutation and name 5 types:

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generates new variation

Somatic
Germ-line
Deleterious
Neutral
Advantageous
adaptations

Front 7

Somatic

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Mutation occurring in the somatic cells as opposed to the germ cells.

-in a chromosome not a sex cell

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Germ-line

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mutation in a sex cell

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Deleterious

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Deleterious mutation is a type of mutation effect that affects the phenotype and in turn reduces the fitness of an organism.

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Neutral

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doesnt affect usually passed on

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Advantageous

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positive advantage, passed on

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Recombination-

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shuffles mutationsto create new combinationsof mutations -both of whichresult in new alleles beingformed.

Front 13

Allele Frequencies

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The frequency of an allele is simply the number of that particular allele present in a population divided by the total number of alleles

Front 14

How are genotype frequencies determined?

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Observable traits

Gel electrophoresis

DNA sequencing

Front 15

Observable traits:

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Easy to determine -count the number of individuals displaying the variant forms of a trait.

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Observable traits:
But this method fails to consider:

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Traits that are encoded by more than one gene

The effects of the environment in which the population is found

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Evolution

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A change in allele or genotype frequency in a population over time
So evolution is a change in the genetic makeup of a population over time
NOTE: populations evolve, not individuals
There are many mechanisms that can cause allele or genotype frequencies to change (next lecture)

Front 18

Hardy-Weinberg Equilibrium 5 conditions:

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There can be no differences in the survival and reproductive success of individuals (selection)

Populations must not be added to or subtracted from by migration.

There can be no mutation.

The population must be sufficiently large to prevent sampling errors.

Individuals must mate at random