Brainlag PlusGenetic and environmental variation, mutations, natural selection, antibiotic resistance, fossils, extinction and how new species form.
Where variation comes from
Differences between individuals of a species are variation.
Some is genetic (blood group), some is environmental (a scar), and much is both (height, body mass).
New alleles come from mutations: random changes in DNA that happen all the time. Most have no effect on the phenotype. Very rarely a mutation gives a phenotype that suits the environment, and it can spread quickly through a population.
The rest of this lesson and its 10 practice questions are in Plus.
Screen 1 of 3, free to read.
- 10 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards