17. The Evolution of Animals

Which of the following statements applies evolutionary thinking correctly and does not propagate a common misconception?

“Lekking” is a common mating behavior seen in organisms ranging from insects to birds. The males in a population gather in one area to display; this group is known as the “lek”. The females then evaluate the males and choose with which males they will mate. Which statement below best explains this behavior in terms of natural selection?

“Invasive species” are species that, when introduced to a new environment, immediately spread rapidly, outcompeting many native species. Which of the following statements describes why a particular introduced species might be so successful in a new environment?

Bt Delta endotoxin is a protein produced by bacteria that kills caterpillars. Scientists have engineered crops that produce this toxin in their leaves, meaning they do not need to spray their fields because the insecticide is being produced by the plant at all times. Over time, however, many species of insects are now showing resistance to these Bt-producing plants. Why do you think this is?