genetics

• Living organisms that belong to the same species, or type, differ from one another in a large number of ways
• Variation



  Differences between individuals for a particular characteristic
• Causes of variation


  •Differences in the genetic makeup (inherited from parents)

  •Enviromental factors
• Some types of variation may be due to only one of the two causes (genetic or enviromental)
• Eye colour


  Determined by genetics (inherited)
• Height in humans

  Affected by both genetic (potential based on parents) and environmental (factors like malnutrition and disease) influences
• Differences in the apperance of identical twins are due to environmental factors such as ; diet, healthcare, life experiences
• • All living organisms produced by sexual reproduction are different from each other because their genes are different
• Evolution is the process whereby populations of organisms change over time
• Mutations that change the genetic makeup of organsisms also cause variation
• Environmental variation



  Variation caused by the surrounding environment, particularly obvious in plants
• Chromosome number varies depending on species. Humans have 23 pairs of chromosomes (46).