Variation Flashcards
What is variation?
The differences that exist between individuals. Every individual organism is unique, as even clones show some variation.
What is intraspecific variation? Give an example
- 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
What is interspecific variation? Give an example
- 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
What is continuous variation? Give an example
- 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
What is discontinuous variation? Give an example
- 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
Explain how variation is caused by genetic factors
-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
Explain how variation is caused by environmental factors
- 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
Explain how variation can be caused by both genetic and environmental factors
- 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