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?

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?

Which of the following statements about homologs are true?

I) Phylogenetic trees of different taxa can be made using orthologs but not paralogs.

II) A gene family is a group of paralogs within a genome.

III) Orthologs are homologs that are found in different species.

The different genes that code for the photoreceptive proteins that function in the vertebrate eye are all believed to be paralogs. Which statement below is most consistent with this idea? 

What is one challenge to trying to date a speciation event using a molecular clock?