Science Week 2

• How many chromosomes are in a human body cell?

  46 chromosomes
• How many pairs of chromosomes are in a human body cell?

  24 chromosomes
• What genes do sex chromosomes carry?

  The genes that determine sex
• What are the two sex chromosomes in females?

  XX
• What are the two sex chromosomes in males?

  XY
• Define evolution

  A change in the genetics of a population over many generations
• What are the three stages of evolution?


  Variation, Natural Selection, Inheritance
• How does one species become two species?

  Two populations become so different that they can’t interbreed
• What is the theory of evolution?

  All species have evolved from simple life forms billions of years ago
• What is natural selection? 

  Individuals with advantageous phenotypes are more likely to survive, reproduce and pass on their genetic information  
• What is a species? 


  A population that can interbreed to produce fertile offspring  
• What is selective breeding? 


  Humans breeding plants and animals for particular characteristics
• Define variation?

   Differences in the characteristics of individuals in a population   
• What causes genetic variation? 

  Random Mutations  
• What effect do most random mutations have on a gene?

   No effect