The Process of Microevolution

Selection: Directional, Stabilizing, and Disruptive Selection

Microevolution vs. MacroevolutionMicroevolution: change in allele frequencyMacroevolution: formation of new species

Microevolution

The environment selects the best traits in the form of alleles that are advantageous for the given conditionsi.e. the ability to digest a new food, or a new skin pigment may allow an organism to blend in with its environmentGenotype = genetic make-up, what alleles an organism hasPhenotype = appearance, what it looks like

Examples of Microevolution

Case 1: English Pepper MothCase 2: Mystery Predator

The common denominator in each of these cases is the change in the alleles of a given gene or set of genes

If there is a change in the frequency of the allele(s), then there will be a change in the genotype and phenotype of the population

Before industrial revolution After industrial revolution

English Peppered Moth

M and M’s in the wild

The “M and M” Predator

• Showing effects of different M & M colors surviving over time

Your turn!Be the chocolate predator…

• Empty M and M bag on table.

• Place colors on matching dots.

• Place colors that don’t match (green) wherever you have space.

• Now, EAT your M and M prey that don’t match (easiest to find)

M and M Population-Before Predation

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Type of M and M

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1st Bag Blue 1st Bag Red 1st Bag Yellow 1st Bag Green 1st Bag Orange 1st Bag Brow n

M and M's After Predation

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Color of M and M

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Blue After Red After Yellow After Green After Orange After Brow n After

M and M Population-After Predation

Microevolution effects on populations over time

Life history patterns = how species reproduce

How successful each of the variations in species will be at reproducing

Which M and M’s color will likely have a frequency change?

Poor M & Ms!