As I’ve said in my response to previous chapters, changes in a population’s gene frequencies can produce rapid change in the short term, yet that alone is not sufficient to drive the large-scale changes that evolution proposes to explain the history of life. But if it is a genuine evolutionary change, Dawkins says he would expect natural selection to result in changes in gene frequencies in the population. Nevertheless, I am inclined to take seriously the possibility that it is a true evolutionary trend. It could be that the difference between large-tusked and small-tusked elephants is a non-genetic difference. It could be that we are observing strong natural selection, which is highly likely to result in changes in gene frequencies in the population, but such genetic effects have not so far been demonstrated. We must be cautious before concluding too much. We must seriously entertain the possibility that it is a true evolutionary trend, in which case it is a remarkably rapid one. Dawkins is hesitant to definitively interpret it as an evolutionary change, since as he says, it could be due to other environmental factors. Between 19, average tusk weight declined from approximately 54 pounds down to 38 pounds. coli experiments.ĭata from the Uganda Game Department (published in 1962) shows a declining trend in tusk weight in Ugandan elephants. He includes the famous Lenski long-term E. Dawkins presents several cases of change within a short time (just a few decades). In chapter 5, Dawkins continues with a point that he began in chapters 2 and 3: we can see evolution in action even on a short time-scale if such changes can occur on such a short time-scale, then an ancient earth gives evolution the time it needs to work its wonders.
0 kommentar(er)
