Homework 7 Genetics 453 due March 2

1. In a swamp you find two types of orchids, one that seems to grow only on the dry meadows (and has red flowers) and another one that happily grows in the swampy meadow (and has yellow flowers). In the zone between these two meadows you can find only few plants, and the ones you find look intermediate and have orange flowers (you do not find any more redish or more yellowish flowering plants). What is going on here?

2. What effect has migration between small populations that have reached different adaptive peaks. Can you explain under the assumption that

   1. the populations are reproductively isolated,
   2. there is no reproductive isolation.

3. Icefishes in Antarctica have lost their hemoglobin. They can survive without it because of the fact that cold water can transport just enough oxygen so that they survive, they also have antifreezing proteins. There exist many icefish species but only a few others. The icefish developed many different adaptations and fill many of the possible ecological niches. Describe the future (rather longterm) of these icefish species under the following viewpoints:

   1. of a gradualist
      1. environment stays the same and is stable
      2. environment changes (e.g. warms up)
   2. of a punctuated-equilibrist.
      1. environment stays the same and is stable
      2. environment changes (e.g. warms up)