Download Common Student Misconceptions About Evolution by Natural

Common Student Misconceptions About Evolution by Natural Selection
The main four we will be addressing in this lab
1.
Selection is between the “normal” phenotype and a “genetic mutant” individual (rather than
continuous variation, and phenotype and genotype are conflated into one thing)
 We will be trying to replace the idea of a mutant individual with the idea of variation
within a population in part I of the lab.
2. Fit organisms survive/thrive, while the rest die (yes/no as opposed to more or less, and uniform
for each type rather than just a difference on average). Another version of this: fit individuals
pass on their genes, while the rest don’t.
 We will be trying to replace this dichotomy with a relative, quantitative measure of the
strength of selection (the selection differential, S) in part II of the lab.
3. All individuals pass their traits directly to their offspring through genetic inheritance (no
possibility of traits being influenced by both genes and environment, plus they tend to forget
about sexual reproduction)
 We will be trying to replace individual inheritance with a population-level measure of
parent-offspring resemblance (heritability, h2, the proportion of variation in offspring
traits that can be explained by their parents’ traits) in part III of the lab.
4. Evolution has occurred when the bad phenotype dies out and everyone has the new mutation
(rather than being a small or gradual change).
 We will try to replace this extreme-change view with a more precise definition of
evolution as a change in proportions or mean value across generations (the response to
selection, R) at the end of the lab.
Secondary misconceptions you may encounter and can address during the lab
1. Evolution happens only when there is environmental change, such as a drought or pollution
(rather than selection and evolution being common and continually occurring processes).
2. Evolution causes species to be stronger/be more successful/become a new species (benefit to
the species argument, failure to distinguish evolution from speciation).
3. Evolution replaces worse traits with better traits (a progressive view of evolution rather than
traits being adaptive in a specific environment).
4. Evolution = natural selection (rather than evolution being caused by many different forces such
as migration, mutation, or drift; failure to distinguish processes occurring in different
generations -natural selection in one generation, evolutionary response to it in the next)
5. Better adapted populations/species replace more poorly adapted populations/species (rather
than selection acting on individuals within a single population).
6. Beneficial mutations occur in response to the new environment (rather than mutation being
random and continually being generated).
7. Natural selection is when individuals compete over food/are “selected” by predators (failure to
generalize from specific examples like industrial melanism, Darwin’s finches).
8. Fit individuals are strong, while unfit individuals are weak (selection as a physical struggle rather
than just a difference in number of offspring).
9. Individuals adapt (populations adapt, not individuals)
10. Organisms adapt to selective pressures like antibiotics by building up tolerance to them over
time (confusion of physiological adaptation with evolutionary adaptation)
11. Organisms adapt to selective pressures by figuring out/learning how to respond to them
(confusion of learning with adaptation)