Evolution

Myths and Misconceptions

Individuals Evolve

• WRONG– Why is this wrong?

• Change can only be measured in a population when the particular adaptation becomes more common.

– EX: peppered moths

• Just because one individual has a new adaptation does not mean that they have evolved

– Adaptation may not be useful

– Adaptation does not give reproductive advantage

– Adaptation may not be heritable

• CORRECT: POPULATIONS Evolve

Evolution Produces Perfection

• WRONG– Why is this wrong?– No organism is perfectly adapted– Every adaptation has a cost and a benefit

• EX: Turtle shell

• CORRECT: Organisms are not perfectly adapted.

Evolution can produce brand new adaptations from nothing.

• WRONG– Why is this wrong?

• Evolution and natural selection can only work on genes that are present in the population; it cann not produce new adaptations

• Evolution “tinkers”. It remodels old adaptations which are beneficial in changing environments

– EX: human limbs and vestigial organs

• Correct: Evolution is best described as descent with modification. In other words, evolution remodels old adaptations.

More Evolved Equals Better

• WRONG– Why is this wrong?

• Any living species is alive because it has survived in it’s environment and reproduced

• “Recently” evolved species are not “better” because they are “newer”

• EX: Bacteria vs. Humans—Who will be more successful?

• CORRECT: New species are NOT better than older species.

Evolution has a Purpose for Every Organism

• WRONG– Why is this wrong?

• How evolution acts upon an organism depends on the environment AT THE TIME

• Useful adaptations in one environment can be useless in another– EX: Polar bears, white rabbits, albinos, Darwin’s finches

• An organism’s phenotype is determined randomly (due to laws of segregation and independent assortment and crossing over.

– Natural selection selects phenotypes that give organisms a reproductive advantage. If the environment changes, the adaptation may be useless.

• CORRECT: Evolution is situational. Organisms do not have adaptations because they “need” them.

What is the Misconception?

• Humans are better adapted to survive on Earth because we are very complex organisms.

• The ancestors of birds grew feathers because they wanted to fly.

• If a cow produces more and more nutritious milk than others in the herd, it has evolved.

• Humans represent the best adaptations that evolution has produced.

• Human adaptations will work in any environment.