ch 8 Mechanisms of Evolution Key concepts

Recall the importance and strength of a scientific theory

A hypothesis that has been repeatedly tested and not yet falsified

Differentiate evolution from natural selection

Evolution is change over time or descent with modification whereas natural selection is differential reproductive success

Discuss early thoughts of evolution (antiquity - Darwin’s time)

Began with Aristotle with the ladder of nature (very generalized, hierachy of abiotic to biotic facts, not accurate)
Next with Linnaeus, known as the father of taxonomy order
Next with James Hutton, proposed idea of gradualism through major geological changes
Next with Charles Lyell, father of modern geology, expanded knowledge of Hutton’s idea known as uniformitarianism
Next with Lamarck, known as lamarckism, stupid thinking
Ending with Charles Darwin and Alfred Wallace, developed evolution theory, and natural selection mechanism.

Aristotle, Linnaeus, Hutton, Lyell

Began with Aristotle with the ladder of nature (very generalized, hierachy of abiotic to biotic facts, not accurate)
Next with Linnaeus, known as the father of taxonomy order
Next with James Hutton, proposed idea of gradualism through major geological changes
Next with Charles Lyell, father of modern geology, expanded knowledge of Hutton’s idea known as uniformitarianism

Outline on the origin of speices

2 hypothesis: evolution is descent with modification and natural selection is differential reproductive success

3 observations: mostly all populations are fairly stable, organism produce more offspring than needed to replace them, environmental resources for life are limited.

2 inferences: differential reproductive success among individuals are selective and lead to adaptations. therefore 2. adaptations accumulate over time as way to best fit environment

Define natural selection and explain its importance to evolution/theory

Natural selection is differential reproductive success, it’s important to evolution because it sets the basis of organisms that have the best traits survive and reproduce in their current environment which can lead to adaptations.

List and discuss the 4 postulates of natural selection

1. phenotypic variation

2. heritability

3. competition

4. fitness (reproduction & survival) not random

Phenotypic variation, give examples, interpret data/graphs

Individuals within populations are variable; ex of birds having different beaks affected by environment, interpret slope 1 = all geno, 0 = pheno

Heritable phenotypic variation - be able to calculate heritability

H2 = Vg/Vp
Vp = Vg + Ve

H2 - heritability
Vg - genotype variation
Vp - population variation
Ve - environmental variation

if H2 was 0 = no genetic variation, all environment dependent
if H2 was 1 = no environmental variation, all genetic dependent

Survival and/or reproductive success variation

Is matin success nonrandom

Discuss the concepts of N.S. and clarify their meanings

Explain what was missing from Darwin’s theory

Genetic and phenotypic variation

Differentiate micro from macro evolution and provide examples of each

Micro - happens within changes of allele frequencies
Macro - morphology changes (huge)

Explain and give examples of evidence of evolution

Micro - soapberry bugs, beak size changes because of the invasive goldenrain tree leaves being smaller than their original tree leaves.
Macro - phylogenetic trees

Vestigial structure, fossil record, homology vs analogy

Vestigial structure - structures originated from ancestor that is no longer used as the same function present day. Example: human’s wisdom teeth, we no longer chew tough, raw food now that cooking has greatly evolved.

Fossil record - show period time frame of organisms that also show a possible side branch that is extinct

Homology - structures that derive from a common ancestor that may be modified for different functions. Example: divergent evolution; mammals forelimbs

Analogous - structures that are not derived from a common ancestor that is found in two different organisms. Example: convergent evolution; birds and butterflies fly, but dont share common ancestor

Differentiate divergent vs convergent evolution

Divergent is when 2 or more organisms derive from a single common ancestor
Convergent is anatomically different, functional similar, obtained by evironmental stress and need, not common ancestor