TM04 Essay Example | Topics and Well Written Essays - 750 words

TM04 - Essay Example [31 words] (c) Why might carrying out the same analysis using species rather than families be likely to be less accurate as an assessment of changing diversity if there were a small number of fossils? Explain what working assumption is made when family diversity changes are used to infer patterns of species change. (3 or 4 sentences) Carrying out the same analysis using species rather than families might be less accurate. There are certain to be more new growths of species besides families. The assumption made when family diversity changes are made to infer patterns of species change is that family diversity changes take as long as species changes, but changes in families take longer time to complete. (e) Given the time period considered in (d) compared to (a), estimate the difference in the rate of the species generation (in percentage per million years) at the end of the Cambrian compared to the period from the end of the Permian to the present day, assuming that the rate of extinction is the same. [62 words] The difference in the rate of species generation per million years would be 10.6 percent; this is based on the fact that the Cambrian period was 570 million years ago, the Permian period was 248 million years ago, and if you divide the difference of the two by the difference between the two percentages given, you get 10.6 percent per million years. (a) Molecular clock evidence suggests that a newly discovered group of animal first emerged about 1.2 billion years ago. This is significantly earlier than the fossil evidence. Describe one possible reason for this discrepancy. (1 to 2 sentences) (c) The evolution of the Ediacarans has been linked to the Snowball Earth episodes. Outline one mechanism linked to ocean temperature that could have influenced animal evolution. (2 to 3 sentences) [27 words] â€Å"When one organism actually lives inside the other its called endosymbiosis. The endosymbiotic theory describes