Aim: Why did Gregor Mendel’s experiments with pea plants lead to the science of genetics?

Text Ch 11 Introduction to Genetics

Read pages 262 – 269

HW # 6 pg. 266 q 1-5 on loose leaf

pg. 269 q 1-5

Gregor Mendel, The Father of Genetics

• The science of genetics was born in 1856, when an Austrian monk named Gregor Mendel performed an historic series of experiments on pea plants, thus discovering the laws of heredity.

Seed Shape

Flower Position

Seed CoatColor

Seed Color

Pod Color

Plant Height

PodShape

Round

Wrinkled

Round

Yellow

Green

Gray

White

Smooth

Constricted

Green

Yellow

Axial

Terminal

Tall

Short

Yellow Gray Smooth Green Axial Tall

Section 11-1

Figure 11-3 Mendel’s Seven F1 Crosses on Pea Plants

Go to Section:

Characteristics of the Pea Plant

Section 11-2

Tt X Tt Cross

Go to Section:

Punnett Square to determine the probability of offspring

P Tall X Short

TT tt

F1

Key

P = parents

F1 = First generation

F2 = Second generation

Section 11-2

Tt X Tt Cross

Go to Section:

F1 Hybrid Tall X Hybrid Tall

F2 generation

Groups: Work out these probabilities using the Punnett Square

P Round X Wrinkled seed shape

F1

F2

P Yellow X Green seed color

F1

F2

P Gray X White seed coat color

F1

F2

Use a 16 box Punnett Square to follow 2 traits of the pea plant

F1 dihybrid tall yellow X dihybrid tall yellow

Incomplete Dominance

Both alleles have an effect on the phenotype of the organism

concluded that

which is called the

which is called the

GregorMendel

Law ofDominance

Law ofSegregation

Peaplants

“Factors”determine

traits

Some alleles are dominant,

and some alleles are recessive

Alleles are separated during gamete formation

Section 11-3

Concept Map

Go to Section:

experimented with

Mendel’s Principles

Today we know “Factors” are genes