BIOL 322 Exam 3 (Ch. 16, 17, 20, and adaptations) Questions and Correct Answers

In order to test the Red Queen hypothesis in snails, Lively collected samples of 40-100 snails from different lakes and streams across New Zealand, assayed parasitic infections in these snails, and determined the frequency of males in each sample. Examine his results summarized in the following figure and choose the best explanation for these results. The proportion of males correlates with the frequency of sexual individuals, and it is an indication that sexual reproduction prevails in highly infected populations In one type of asexual reproduction, an unfertilized egg undergoes a division similar to mitosis, producing two daughter cells genetically identical to the mother. This type of asexual reproduction is known as: apomixis N. Barton and B. Charlesworth (1998) defined sexual reproduction as the process that involves the joining together of genetic material from two parents to produce an offspring that has genes from each parent. More specifically, such process, which involves meiosis and gamete fusion, is called: amphimixis Virtually all eukaryotes reproduce sexually either at some point in their life cycle or periodically across generations, while prokaryotes have other mechanisms to preserve genetic variability and exchange new mutations. This is sometimes referred to as a form of "sexual reproduction" in bacteria. Which of the following is not one of the mechanisms of genetic exchanges in prokaryotes? Syngamy Which of the following is a phylogenetic method that can distinguish between asexual and sexual lineages of eukaryotic organisms? analysis of nDNA- and mtDNA-based trees Which of the following statements is not true regarding asexual reproduction in animals? Asexual taxa are longer lived (last longer in evolutionary time). Anisogamy (different-size gametes) is a phenomenon found in many sexually reproducing species. Which of the following assumptions might contribute to the notion that natural selection favors anisogamy? all of the above: There is a trade-off between the size of gametes and the number of gametes; The larger the gamete, the less mobile it is; and The probability that a zygote survives increases with its size, and the size of the zygote is a function of the sizes of the fusing gametes