Variation

• Characteristics of animal and plant species can be affected by factors such as:

  • Climate
  • Diet
  • Accidents
  • Culture
  • Lifestyle
• Examples of features that show environment variation are:

  • Scar or accident
  • Flower colour in hydrangeas (They produce blue flowers if soil is acidic and pink if alkaline is in soil)
• For any species, a characteristic that changes gradually over a range of values shows continuous variation. Examples of characteristics are:

  • Height
  • Weight
  • Hand span

  Height ranges from the shortest person and the tallest person. Any height is possible between these two extremes.

  This is called a bell shaped curve

  
• A characteristic of any species with only a limited number of possible values shows discontinuous variation. E.g.:

  • Gender
  • Eye colour
  • Blood group

  Human beings have only 4 blood groups. There are no values in between.

  
• Only one parent is needed in asexual reproduction. No fusion of gametes so genetic material does not mix. Example of organisms that use asexual reproduction are:

  • Bacteria
  • Production of spores by fungi
  • Strawberries
  • Formation of tubers in potatoes