genes

• What is evolution?


  It is how living things change over time and how

  new species develop over thousands of

  generations.

  Charles Darwin proposed that evolution took place

  through natural selection.
• What evidence is there for evolution?

  Fossil records show how species have changed

  over millions of years
• What is meant by the term genetic modification?


  This process involves moving a gene or genes from

  one species to another.
• Give an example of how a plant has been genetically

  modified:

  Crops have been modified to be resistant to insect

  attack
• describe how natural selection lead to giraffes having long necks

  There is variation between the length of the neck in the

  population

  • There is competition for food

  • The giraffes with the longer neck are more suited to the

  environment and more likely to survive – survival of the

  fittest

  • The giraffes with

  longer necks are more

  likely to reproduce

  passing on their long

  neck genes.
• Place in order from smallest to largest: gene, chromosome, nucleus, cell:

  gene, chromosome, nucleus, cell
• What does DNA mean

  Biological molecule that determines

  your characteristics
• What is a chromosome

  Is found in pairs is tightly packed DNA
• What are genes 


  A section of DNA that codes for a particular characteristic
• What is an allele 


  A version of a gene that determines a

  characteristic
• What does extinction mean? Give an example of an extinct animal.


  The process of a species dying out. E.g. Dodo
• What factors may cause an organism to become endangered or extinct?

  Climate change, natural disasters, hunted by humans, hunted by non-native animals, disease, loss of habitat
• Identify some conservation methods to prevent organisms becoming extinct.


  Laws to prevent the hunting of endangered species, limiting climate change, nature reserves to protect habitats
• What is the shape of DNA?

  double helix
• What does DNA stand for?

  Deoxyribonucleic acid
• How many chromosomes are found in

  most human cells?

  46 (23 pairs)