Variation

Question 1

What is variation?

Answer 1

The differences that exist between individuals. Every individual organism is unique, as even clones show some variation.

Question 2

What is intraspecific variation? Give an example

Answer 2

• variation within a species
• for e.g individual European robins weigh between 16g and 22g, and can show variation in other characteristics such as length, colour and wingspan

Question 3

What is interspecific variation? Give an example

Answer 3

• variation between species

- for e.g the lightest species of bird weighs 1.6g on average, whilst the heaviest bird can weigh up to 160kg

Question 4

What is continuous variation? Give an example

Answer 4

• when the individuals in a population vary within a range, there are no distinct categories
• e.g humans can be any height within a range, not just tall or short

Question 5

What is discontinuous variation? Give an example

Answer 5

• when there are 2 or more distinct categories which each individual falls into one of these
• e.g blood group, humans can be group A, B, AB, or O

Question 6

Explain how variation is caused by genetic factors

Answer 6

-different species have different genes, but individuals of the same species have the same genes, but different versions of (alleles), making up an organisms genotype

• the differences in genotype result in variation in phenotype (characteristics displayed by an organism)
• variation caused by genetic factors is inherited

-e.g of variation caused only by genetic factors is human blood groups

Question 7

Explain how variation is caused by environmental factors

Answer 7

• differences in the environment = climate, food, lifestyle
• characteristics controlled by environmental factors can change over an organisms life
• e.g of variation caused only by environmental factors include accents and if people have pierced ears

Question 8

Explain how variation can be caused by both genetic and environmental factors

Answer 8

• genetic factors determine the characteristics that an organism’s born with, but environmental factors can influence how some characteristics develop.
• e.g height= genes determine how tall an organism can grow, but diet or nutrient availability affect how tall an organism can actually grow