Quick Lab
GUIDED INQUIRY

Classroom Variation

  1. Copy the data table into your notebook.

  1. Write a prediction of whether the traits listed in the table will be evenly distributed or if there will be more dominant than recessive traits.

  1. Examine your features, using a mirror if necessary. Determine which traits you have for features A–E.

  1. Interview at least 14 other students to find out which traits they have. Tally the numbers. Record the totals in each column.

    Analyze and Conclude

  1. Calculate Calculate the percentages of each trait in your total sample. How do these numbers compare to your prediction?

    A table of trait survey of dominant and recessive trait.d

  2. Form a Hypothesis Why do you think recessive traits are more common in some cases?

In Your Notebook Make a diagram that explains Mendel's principle of dominance.

Segregation

How are different forms of a gene distributed to offspring?

Mendel didn't just stop after crossing the parent plants, because he had another question: Had the recessive alleles simply disappeared, or were they still present in the new plants? To find out, he allowed all seven kinds of F1 hybrids to self-pollinate. The offspring of an F1 cross are called the F2 (second filial) generation. In effect, Mendel crossed the F1 generation with itself to produce the F2 offspring, as shown in Figure 11–4.

The F1 Cross When Mendel compared the F2 plants, he made a remarkable discovery: The traits controlled by the recessive alleles reappeared in the second generation. Roughly one fourth of the F2 plants showed the trait controlled by the recessive allele. Why, then, did the recessive alleles seem to disappear in the F1 generation, only to reappear in the F2 generation?

An illustration showing Results of the F1 Cross experiment conducted by Mendel. When Mendel allowed F1 plants to reproduce by self-pollination, the traits controlled by recessive alleles reappeared in about one fourth of the F2 plants in each cross.

FIGURE 11–4 Results of the F1 Cross When Mendel allowed the F1 plants to reproduce by self-pollination, the traits controlled by recessive alleles reappeared in about one fourth of the F2 plants in each cross. Calculate What proportion of the F2 plants had a trait controlled by a dominant allele?

End ofPage 311

Table of Contents

Miller & Levine Biology
About the Authors
Changing the World of Biology Education
Contents
Diversity of Life: A Visual Guide DOL•1–DOL•64
Labs and Activities
Features
UNIT 1 The Nature of Life
1 The Science of Biology
2 The Chemistry of Life
Unit Project
UNIT 2 Ecology
3 The Biosphere
4 Ecosystems and Communities
5 Populations
6 Humans in the Biosphere
Unit Project
UNIT 3 Cells
7 Cell Structure and Function
8 Photosynthesis
9 Cellular Respiration and Fermentation
10 Cell Growth and Division
Unit Project
UNIT 4 Genetics
11 Introduction to Genetics
12 DNA
13 RNA and Protein Synthesis
14 Human Heredity
15 Genetic Engineering
Unit Project
UNIT 5 Evolution
16 Darwin's Theory of Evolution
17 Evolution of Populations
18 Classification
19 History of Life
Unit Project
UNIT 6 From Microorganisms to Plants
20 Viruses and Prokaryotes
21 Protists and Fungi
22 Introduction to Plants
23 Plant Structure and Function
24 Plant Reproduction and Response
Unit Project
UNIT 7 Animals
25 Introduction to Animals
26 Animal Evolution and Diversity
27 Animal Systems I
28 Animal Systems II
29 Animal Behavior
Unit Project
UNIT 8 The Human Body
30 Digestive and Excretory Systems
31 Nervous System
32 Skeletal, Muscular, and Integumentary Systems
33 Circulatory and Respiratory Systems
34 Endocrine and Reproductive Systems
35 Immune System and Disease
Unit Project
A Visual Guide to The Diversity of Life
HOW TO USE THIS GUIDE
THE TREE OF LIFE
Bacteria
Protists
Fungi
Plants
Animals
Appendices
Appendix A Science Skills
Appendix B Lab Skills
Appendix C Technology & Design
Appendix D Math Skills
Appendix E Periodic Table
Glossary
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q, R
S
T
U
V
W
X, Y, Z
Index
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Credits
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