21. Evolution

Which statement below best restates one of the key observations central to the concept of Natural Selection?

In a population of crickets, all crickets make a “chirp” to attract mates at the same rate. Chirping also attracts predators, however. In one season, more than 50% of the crickets are eaten as prey as a result of chirping. In this simplified example, using only the information given, do you think this population will evolve by natural selection and why?

Herbicides, chemicals administered by farmers to kill weeds, have been hugely beneficial in increasing the efficiency of modern agriculture. Many of the herbicides used today, however, are less effective than when they were originally introduced because weed populations have evolved resistance. Knowing this, which of the following statements is likely true?

Which of the following statements correctly explains a way in which evolution by natural selection and Lamarck's ideas about evolution are different?