Variation & Inheritance (C4)

• importance of variation (2 marks)

  it provides the world with a diversity of organisms ; prevents extinction of species when the environment changes
• what is inheritance?


  the passing of traits from parents to offspring which is passed on during reproduction and happens from generation to generation
• where can genes be found?

  they are located on the chromosomes found in the nucleus of a cell
• what is selective breeding?

  to select individuals with desirable characteristics and breed them together
• what are the benefits of selective breeding? 


  helps human population to grow by providing increased yields and quality of plant products
• disadvantages of selective breeding? (2 marks)

  it can lead to inbreeding ; it results in a reduction in the gene pool, which is less variation of genes in the population
• what is natural selection?

  the process whereby organisms better adapted to their environment tend to survive n produce offsprjng
• what are the principles of natural selection? (4 marks)

  overproduction, variation, selection, adaptation
• what is overproduction in natural selection?

  populations create more offspring that can survive and reproduce
• what is adaptation in natural selection 


  population possesses traits that make them able to survive