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1. The quote means that there were many other species before humans existed. It is hard to imagine but in the calendar, which represents earth’s history, it is clearly demonstrated. The calendar consists of twelve months and we are in the last month on the last day. That means for about 800 million years if not more, life still existed without humans. After the earth formed, rocks formed, chemical evidence of life, which soon produced fossil cells was also formed. Eukaryotes, algae, first animals with limbs and shells, first animals with vertebrae, land plants, land animals and dinosaurs all appeared before us. They were also extinct before us as well. Most people think that dinosaurs were a very long time ago and they do not even realize that before dinosaurs, there was still much more life on Earth. It is amazing to know that we may not be around forever either. In another 800 million years, new life forms may not even be able to relate to us, like we cannot relate to fossil cells that much.
2. Convergent evolution is the way that natural selection has made use of the different mutations available in each population to accomplish the same adaption. The evidence that lactose tolerance arose by convergent evolution is the University of Maryland tested forty-three ethnic groups in East Africa and found three separate mutations. They were all different from the European one, which kept the lactase gene switched on in adulthood. One of the mutations, found in peoples of Kenya and Tanzania, may have arisen about three thousand years ago. The lactose tolerance has evolved independently four times is an instance of convergent evolution. Natural selection has used the different mutations available in European and East African populations to make each develop lactose tolerance.