Evolution and Natural Selection

Natural Selection does not produce perfection, just “good enough”.

TRUENatural selection is not all-powerful; it

does not produce perfectionIf your genes are “good enough,” you’ll

get some offspring into the next generation—you don’t have to be perfect

Natural Selection has no goals; it’s not striving to produce “progress” or a balanced ecosystem

TRUENatural selection is a process rather than a

guiding handNatural selection is the simple result of

variation, differential reproduction, and heredity

It is mindless and mechanistic. It has no goals; it’s not striving to produce “progress” or a balanced ecosystem.

Natural Selection is a random process

FALSEThe genetic variation that occurs in a

population because of mutation is randomSelection acts on that variation in a very

non-random way: genetic variants that aid survival and reproduction are much more likely to become common than variants that don't

Evolutionary theory implies that life evolved (and continues to evolve) randomly, or by chance

TRUE AND FALSEChance and randomness do factor into

evolutionImportant mechanisms of evolution are non-

random and these make the overall process non-random --- selection

Process of mutation, which generates genetic variation, is random, but selection is non-random

Evolution results in progress; organisms are always getting

better through evolutionFALSENatural selection does result in the

evolution of improved abilities to survive and reproduce

Mutation, migration, and genetic drift may cause populations to evolve in ways that are actually harmful overall or make them less suitable for their environments

Evolution produces a tree, not a ladder

Individual organisms can evolve during a single lifespan

FALSEPopulations, not individual organisms,

evolveEvolutionary change is based on changes

in the genetic makeup of populations over time

Evolution only occurs slowly and gradually

TRUE AND FALSEEvolution occurs slowly and gradually, but it

can also occur rapidlyOver the past 50 years, we've observed

squirrels evolve new breeding times in response to climate change, a fish species evolve resistance to toxins dumped into the Hudson River, and a host of microbes evolve resistance to new drugs we've developed

Because evolution is slow, humans cannot influence it

FALSEHumans often cause major changes in the

environment, we are frequently the instigators of evolution in other organisms.

Pesticide and bacterial resistence

Genetic drift only occurs in small populations

FALSEGenetic drift has a larger effect on small populations,

but the process occurs in all populationsGenetic drift occurs because, due to chance, the

individuals that reproduce may not exactly represent the genetic makeup of the whole population

In large populations, the changes in gene frequency from generation to generation tend to be small, while in smaller populations, those shifts may be much larger