The success of viruses like HIV lies in their ability to eveolve within the host's body. The HIV virus evades

attacks by the body's immune sysytem by mutating a rapid rate, producing geneation after generation of progeny viruses that change before the body can mount a concerted attack, until eventually the viruses overcome the body's defenses. Thus, the viruses present at a late stage of infection are different from those that initially infected the body, though descended from them. Discuss this as an example of evolutin in micrcosm. Which viral lineages tend to survive?

You're asking us to write your paper for you!

Well - here are a few things to think about.

There are a number of factors that confer survival advantage to HIV:

o Rapid mutation caused by the viral reverse transcriptase
o Tropism for the immune cell receptors by which means the virus enters human cells
o Viral latency - where the human cells are not killed immediately but may continue to function with the viral DNA incorporated into the cellular DNA

In the theory of evolution, the process of natural selection involves the survival of organisms with advantageous mutations and the failure or death of genetic lines with disadvantageous mutations.

Now - how about you doing a little bit of research and writing your own paper.

Some good links to start with are listed below.