Evolution and Natural Selection

Natural Selection does not produce perfection, just “good enough”. TRUE Natural selection is not all-powerful; it does not produce perfection If 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 TRUE Natural selection is a process rather than a guiding hand Natural 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 FALSE The genetic variation that occurs in a population because of mutation is random Selection 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 FALSE Chance and randomness do factor into evolution Important 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 evolution FALSE Natural 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 FALSE Populations, not individual organisms, evolve Evolutionary change is based on changes in the genetic makeup of populations over time

Evolution only occurs slowly and gradually TRUE AND FALSE Evolution occurs slowly and gradually, but it can also occur rapidly Over 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 FALSE Humans 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 FALSE Genetic drift has a larger effect on small populations, but the process occurs in all populations Genetic 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