B6 revision

• What is a mutation?

  A change in the DNA
• What is evolution?

  A change in the Inherited characteristics of a population
• How can you tell that 2 animals are different species?


  They can’t interbreed and produce fertile offspring
• Give 2 reasons why humans might selectively breed farm animals

  • More Meat
  • More milks/eggs
• Give 2 reasons why humans might selectively breed domestic animals

  • Better temperament
  • Colour/Length of fur
• Give 2 reasons why humans might selectively breed plants


  Bigger fruit

  Disease resistant crops
• List one issue that selective breeding may cause 


  Organisms can be vulnerable to harmful diseases
• How have bacteria been genetically engineered to benefit humans?


  They produce useful susbstances such as insulin to treat diabetes
• What are the benefits of GM crops?

  They can be made resistant to insect attacks
• What are the disadvantage of GM crops?

  Concerns of human health as a result of eating GM crops
• What are the two main pieces of evidence for evolution?

  Fossils

  Antibiotic resistance
• Describe 3 ways that fossils may be formed

  Harder parts of an animal are replaced by minerals

  Preserved traces of organisms

  Part of organisms that have not yet been decayed
• Why is there little evidence of early life on Earth?

  Complete organisms are never found

  Incomplete fossil records
• Define the term extinction

  When there are no remaining individuals of a species still alive
• Give 3 main ways that extinction can be caused:

  Loss of habitat

  Pollution

  Competition
• Outline the stages in the development of antibiotic resistance

  Bacteria mutates

  They survive as they are now resistant to the antibiotic

  They reproduce and spread as there is no treatment
• Describe 3 ways to reduce antibiotic resistance

  Patients should Take the full course of antibiotics

  Doctors should only give patients antibiotics when necessary

  Stop using antibiotics in agriculture
• Traditionally, Which factors were used to classify organisms?

  Physical characteristics and structures
• Which factors are now used to classify organisms?

  Improvements in microscopes and genetics mean cellular structures, DNA sequences and bio chemical processed are now used.
• What is MRSA?

  Bacteria that is resistant to antibiotics
• What causes antibiotic resistance in bacteria?

  Bacteria reproduces at fast rates causing mutations
• State Carl Linnaeus order of classification

  Kingdom

  Phylum

  Class

  Order

  Family

  Genus

  Species
• Outline the 3 domains which were proposed by Carl Woese

  Archaea

  Bacteria

  Eukaryota
• State 2 advantages of embryonic screening

  • Prevent people suffering from genetic disorders
  • Reduction in treating disorders can save a significant amount of money
• State 2 disadvantages of embryonic screening

  Expensive process

  Ethics - Embryos that are not used are destroyed which may be considered unethical or against religious views