Variation Flashcards
What is variation?
Variation is the DIFFERENCES that exist between INDIVIDUALS.
What is variation within species?
Variation within species is called INTRASPECIFIC variation.
For example, INDIVIDUAL European robins weigh between 16g and 22g and show some variation in many other characteristics including length, wingspan, colour and beak size.
What is variation between species?
The variation between DIFFERENT SPECIES is called INTERSPECIFIC VARIATION.
For example, the LIGHTEST species of bird is the bee hummingbird, which weighs 1.6grams on average. The HEAVIEST species of bird is the ostrich, which can weigh up to 160kg (100 000 times as much).
What is continuous variation?
Continuous variation is when individuals in a population vary WITHIN RANGE - there are no distinct categories.
Example: HUMANS can be ANY HEIGHT within a range (139cm, 175cm, 185.9cm) NOT JUST tall or short.
Variation in Animals:
> Milk yield
E.G cows can produce any volume of milk within a range.
Variation in Animals:
> Mass
Humans can be any mass within a range.
Variation in plants:
> number of leaves
A tree can have any number leaves within a range.
Variation in plants:
> Mass
e.g. the mass of the seeds from a flower head varies within range.
Variation in microorganisms:
> Width
e.g. the width of E.Coli bacteria varies within range.
Variation in microorganisms:
> length
e.g. the length of a flagellum can vary within range.
What is discontinuous variation?
Discontinous variation is when there are two or more DISTINCT CATEGORIES - each indinidual falls into ONLY ONE of these categories, there are no intermediates.
Discontinuous variation in Animals:
> BLOOD GROUP
e.g. Humans can be group A, B, AB, or O.
Discontinuous variation in plants:
> COLOUR
e.g courgettes are either green, light green or dark green.
Discontinuous variation in plants:
> Seed shape
e.g. some pea seeds have smooth seeds and some have wrinkled seeds
Discontinuous variation in microorganisms:
> Antibiotic resistance
e.g. bacteria are either resistant or not