Variation, mutation and evolution

• What is variation in biology?

  Differences found within the same species
• What causes variation in species?

  Sexual reproduction and environmental influences
• What are the types of variation?

  • Genetic variation
  • Environmental variation
  • Combination of both
• How do children inherit features from their parents?

  They receive half from each parent
• What is a haploid cell?

  A sex cell with one set of chromosomes
• What is a zygote?

  A fertilised egg cell
• What is the difference between haploid and diploid cells?

  Haploid has half, diploid has full chromosomes
• What determines whether a person is male or female?

  The genes inherited from their parents
• What factors can affect environmental variation?

  Climate, diet, accidents, culture, lifestyle
• How does diet affect weight?

  Too much food leads to weight gain
• How does a plant grow in the shade?

  It grows taller to reach more light
• How do hydrangeas change flower colour?

  Based on soil pH levels
• What happens when identical twins have different diets?

  One twin may weigh more than the other
• What are the causes of variation?

  • Genetic causes
  • Environmental causes
  • Combination of both
• What is variation in biology?

  Differences found within the same species
• What causes variation in species?

  Sexual reproduction and environmental influences
• What are the two types of variation?

  • Continuous variation
  • Discontinuous variation
• What does continuous variation refer to?

  Characteristics that change gradually over a range
• Why is height considered continuous variation?

  Any height is possible between two extremes
• What shape does the graph of continuous variation typically take?

  A bell-shaped curve
• What happens to the results as more people are measured in continuous variation?

  Results approach a curved line
• What is discontinuous variation?

  Characteristics with a limited number of possible values
• How many blood groups do humans have?

  Four blood groups
• What are the four human blood groups?

  A, B, AB, and O
• Why does blood group variation show discontinuous variation?

  No intermediate values exist between groups
• What are the key differences between continuous and discontinuous variation?

  Continuous Variation:

  • Changes gradually
  • Examples: height, weight

  
  

  Discontinuous Variation:

  • Limited possible values
  • Examples: gender, blood group
• What is variation in biology?

  Differences found within the same species
• What causes variation in organisms?

  Sexual reproduction and environmental influences
• What is asexual reproduction?

  • Requires only one parent
  • No fusion of gametes
  • Offspring are clones of the parent
• What is a gamete?

  Sex cell (sperm or egg)
• What does it mean for offspring to be clones?

  They are genetically identical to the parent
• Which organisms reproduce asexually?

  Bacteria, fungi, and some plants
• What is a spore?

  A unit of asexual reproduction in some organisms
• What is a tuber?

  A swollen underground stem of a plant
• What is mitosis?

  A type of cell division producing identical daughter cells
• What is sexual reproduction?

  • Requires two parents
  • Each parent produces gametes
  • Fusion of male and female gametes occurs
  • Produces genetically different offspring
• How many chromosomes do human gametes contain?

  23 chromosomes
• What is fertilization?

  Fusion of male and female gamete nuclei
• What is a zygote?

  A fertilized egg cell
• What happens to the number of cells during embryo development?

  The number of cells increases by mitosis