Inheritance and selection

What you'll learn

1. 1

   Imagine you have a bag of 20 marbles: 10 blue and 10 red. You pick one marble at random without looking.

2. 2

   If you pick a marble from the bag, what are the chances it's blue?

3. 3

   Let's work out the chance of getting two blue marbles in a row from the bag (replacing the first one after each pick).

4. 4

   Now try it yourself. The bag has 5 red and 15 blue marbles. What's the chance of picking two reds in a row (with replacement)?

5. 5

   For the bag with 5 red and 15 blue, what's the probability of picking a red marble first?

6. 6

   Now think about inheritance. A pea plant has two alleles for flower colour: one purple (P) and one white (p). Which allele is dominant?

7. 7

   If a plant has one P and one p allele, what colour will its flowers be?