Evolution and the Bird Flu Virus

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What comes to mind when you think of evolution? Most people probably visualize vertebrate evolution, like the way reptiles evolved from amphibians or how amphibians evolved from fish. In fact all species on the planet evolve, even microbes like bacteria. To stay one step ahead of bacterial evolution, scientists are constantly developing new antibiotics to fight them.

What about viruses? Most scientists say don't even consider them living organisms. Even so, viruses definitely evolve. In 1918 and 1919, the infamous Spanish Flu epidemic raged around the planet killing millions of people. The outbreak was the result of a bird virus that mutated or changed into a form deadly to humans.

Scientists are worried that the bird flu virus that's now killing millions of birds in Asia, Europe, and the Middle East will also evolve into a form more deadly to people. In this activity, you'll find out how changes in DNA turn the wheels of evolution and how this applies to the bird flu virus.

To begin, check out this article on Evolution and avian flu. Read the first paragraph.

1. What is the current toll of bird (avian) flu on birds and people?
   
   
   
   
2. How is the bird flu virus spread?
   
   
   
   
3. What specifically are biologists worried about with bird flu?
   
   
   
   
4. Let's take a closer look at natural selection. Use the beetle example shown on the page to illustrate the four steps of natural selection:
   
   1. Variation in traits
      
      
      
      
   2. Differential reproduction
      
      
      
      
   3. Heredity
      
      
      
      
   4. End results
      
      
      
      
5. Return to the Evolution and avian flu page and scroll to Where's the Evolution? What "ingredients" need to be in place for natural selection to occur?
   
   
   
   
6. What do "H5" and "N1" refer to in the H5N1 bird flu virus strain?
   
   
   
   
7. Explain why the H5N1 strain does not pass easily from birds to humans.
   
   
   
   
8. What is a random mutation?
   
   
   
   
9. Explain why viruses evolve so rapidly.
   
   
   
   
10. What is the "most worrisome possibility"?
    
    
    
    
11. Now you'll explore the link between DNA and mutations. What are the four letters of the genetic code and what do they represent?
    
    
    
    
12. What does the sequence of bases on DNA code for? Give some examples.
    
    
    
    
13. What is a codon?
    
    
    
    
14. Next, you'll learn how changes in the genetic code cause different types of mutations. Read the examples and view the pictures on the page. Describe each type of mutation:
    
    1. Substitution
       
       
       
       
    2. Insertion
       
       
       
       
    3. Deletion
       
       
       
       
    4. Frameshift
       
       
       
       
15. You'll now take a look at the causes of mutations. Explain how errors can occur when DNA is duplicated.
    
    
    
    
16. Give examples of how external influences can create mutations.
    
    
    
    
17. Finally, visit the World Health Organization for the latest bird flu update. Click the most recent report at the top of the list. How many victims has the virus now claimed worldwide?