Evolution Answers

(a) A gene called "PRNP" produces the prion protein. In humans there are two alleles for the gene, known as "Met" and "Val". People who are homozygous for the Met allele can contract "variant CJD", the fatal human form of mad cow disease associated with the consumption of infected beef. In Denmark, a survey of 352 individuals found that 131 were homozygous for Met, 168 were heterozygous, and 53 were homozygous for Val. Is the PRNP gene in Hardy- Weinberg equilibrium?

(b) Based on your answer in the last question what effect is the "Met" allele having on the fitness(in the Darwinian sense) of Danes who have it? Explain your answer

What are the significances of colouration?

I have been able to jot down some points but I need some more. The points are:

* Colouration increases the survival value of a species by providing protection (protective colouration), provinding food (alluring colouration) and by helping in reproduction (sexual colouration).
* When different species have same colouration it leads to convergent evolution. e.g. Many wasp, caterpillar moth, grasshopper and arrow poison frogs have black and yellow stripes.
* Animals with darker skin have more melanin and are less vulnerable to skin cancer.