Viruses+Article+ZW

1. "if we are unlucky..." the author writes we will see evolution in action. What does she mean? Why would it by unlucky to see the avian virus evolve. It would be bad to see an evolution in the avian virus because we are still trying to figure out this form of it. Mutation could cause pandemic.

2. Define parasite. Parasites are tiny parcels of genes that are mailed from one organism to the next.

3. Define gene. Genes are units that transfer characteristics from one organism to the next by generation or heredity.

4. She compares viruses to tiny parcels. Why? How are these parcels mailed? “Tiny parcels of genes that are mailed from one organism to another, either directly, through sneezes, feces, semen and the like, or indirectly, through carriers like insects. But these tiny parcels can mean big trouble: viruses reliably feature on nature's roster of top killers.”

5. 20 million people died of the Spanish Flu during World War II. Yet the author claims to know that this flu virus was particularly deadly not that it was a normal virus but because of the war and wartime "deprivation" people were more likely to get sick and die. What two pieces of evidence indicate this was a very deadly virus unlike the normal flu virus. “For one thing, it was particularly deadly in young, healthy adults. For another, in a remarkable feat of genetic engineering, a team of biologists recently reconstructed the 1918 virus and used it to infect mice. The results are sobering. The 1918 virus is far, far more lethal in mice than are other human flu viruses.”

6. What is H5N1? H5N1 is the avian flu virus.

7. Since H5N1 has killed mostly birds, why are we worried about it? We are reasonably worried because of the rate of death and the potential for deadliness.

8. Two processes could change the H5N1 in a deadly way: sex and mutation. What is viral sex and how could it change the virus? What is viral mutation and how could this change the virus? “Sex and mutation: these are not special processes reserved for viruses. They are two fundamental mechanisms of evolutionary invention. Mutations alter the information content of genes; sex shuffles the pack, generating new gene combinations. They sound simple, and they are - but don't let that deceive you. Simple processes can have great power. After all, a few mutations to a bird virus could - in the absence of a vaccine - mean the difference between 60 people dead and several million.”

9. How can mutation lead to evolution (origin of new species)? Mutation can change the DNA structure so that it will become something different.

10. How can sex lead to evolution (origin of new species)? New genes are brought into the virus, therefore it builds into an organism.