Download Chapter 11 Section 2 Notes 11-2 Probability and Punnett Squares

Chapter 11 Section 2 Notes
11-2 Probability and Punnett Squares
Name: ___________________________________ Date: _______________
Period: _____
Objectives:
1. Explain how geneticists use the principles of probability.
2. Describe how geneticists use Punnett squares.
Genetics and Probability:
 The likelihood that a particular event will occur is called _______________________.
 Ex. 1: What is the probability that a single coin flip will come up heads?
 Ex. 2: What is the probability of flipping three heads in a row?
 The principles of _________________can be used to __________________ the outcomes of
_________________________ crosses.
Checkpoint:
 What is the probability that a tossed coin will come up tails twice in a row?
Punnett Squares:
 The ___________ combinations that might result from a genetic ______________ can be
determined by drawing a ______________ known as a _______________ square.
 This Punnett square shows the probability of each possible outcome of a cross between
________________ tall (_____) pea plants.
 _________________ squares can be used to ________________ and _______________ the
_____________________ variations that will result from a _________________.
 Organisms that have two ________________ alleles for a particular trait – TT or tt in this
example – are said to be ___________________ (_______________-_______________ for a
particular trait).
 Organisms that have two ________________ alleles for the same trait – Tt in this example – are
said to be ________________________ (___________________ for a particular trait).
 All of the tall plants have the same ______________________, or ________________
characteristics.
 They do not, however, have the same ______________________, or ______________________
makeup.
 The ______________________ of one third of the tall plants is _______, while the
___________________ of two thirds of the tall plants is _______.
Probability and Segregation:
 One fourth (_____) of the F2 plants have two alleles for tallness (_____).
 _____, or _____, of the F2 plants have one allele for tallness and one allele for shortness (_____).
 Because the __________ for tallness is _________________ over the __________ for
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________________, of the F2 plants should be _______________.
 The ____________ of tall plants to short plants is ______.
Probabilities Predict Averages:
 Probabilities ________________ the average outcome of a ______________ number of events.
 However, probability ____________________ predict the _________________ outcome of an
individual ________________.