Science variation test:

• What does survival of the fittest mean? 


  The individuals with the most favourable characteristics are most likely to survive.
• Describe how the process of selective breeding could be used to increase the yield of tomato plants. 


  Select the two tomato plants with the highest yield from the population.

  Breed them together.

  Once the plants have grown and produced tomatoes, repeat the process by breeding together the ones with the highest yield.

  Keep repeating this over multiple generations, and the average yield will increase. 
• What is variation? 


  The differences in the characteristics of individuals within a population.
• What is inbreeding? 


  The process of mating together closely related individuals.
• What is natural selection? 


  The idea that in each generation, the individuals with the most favourable characteristics are most likely to survive and reproduce, therefore passing on their genes.
• Give three examples of traits that might be selectively bred for in plants or animals. 


  Improved yields, desirable characteristics and drought resistance.
• What effect does selective breeding usually have on variation within a population? 


  It normally decreases the variation within a population.
• Which two factors contribute to the variation between organisms?

  The genes each individual inherits and the environments each individual is exposed to.
• What is genetic engineering? 


  The process of modifying the genome of an organism by introducing a gene from another organism, in order to give a desired characteristic.
• What do we call crops that have been genetically engineered? 


  Genetically modified (gm) crops.
• Give two drawbacks of genetic engineering. 


  They could spread and affect the wild population‘s gene pool, and affect on our health.
• Give three drawbacks of inbreeding.

  1. It reduces the size of the gene pool
  2. Rare inherited diseases are more likely to be expressed
  3. The population as a whole will be more at risk of disease
• Why are regulations important in genetic screening? 


  To prevent gene-based bias and ensure fair treatment in society.
• What is evolution? 


  The process by which the inherited characteristics of a population change over time due to natural selection.
• How has genetic engineering played a role in the treatment of diabetes? 


  Bacterial cells have been genetically engineered to produce human insulin to treat diabetes.
• What is selective breeding? 


  The process by which humans use animal or plant breeding to selectively develop particular characteristics by choosing which males and females will sexually reproduce and have offspring together.
• What is speciation? 


  The evolutionary process by which populations evolve to become distinct species.
• Who was Charles Darwin? 


  A 19th century biologist, who is credited with developing and proposing the theory of evolution.
• Describe the steps of genetic engineering.

  1. Isolate the desired gene from human DNA
  2. Insert the DNA into a vector, such as a plasmid
  3. Insert the plasmid into a host bacterium
  4. Let the bacterium divide and then produce the desired protein
• Give three traits that could be altered by genetic engineering in crops. 


  Increased yield, increased quality and resistance to disease.