VISUAL SUMMARY

INTERPRETING A CLADOGRAM

A Cladogram with frames of Cats, Dogs and relatives, Marsupials, Reptiles and Amphibians.

FIGURE 18–9 This cladogram shows the evolutionary history of cats. In a cladogram, all organisms in a clade share a set of derived characters. Notice that smaller clades are nested within larger clades. Interpret Visuals For which clade in this cladogram is an amniotic egg a derived character?

dd

Interpreting Cladograms We can now put this information together to “read” a cladogram. Figure 18–9 shows a simplified phylogeny of the cat family. The lowest node represents the last common ancestor of all four-limbed animals—members of the clade Tetrapoda. The forks in this cladogram show the order in which various groups branched off from the tetrapod lineage over the course of evolution. The positions of various characters in the cladogram reflect the order in which those characteristics arose in this lineage. In the lineage leading to cats, for example, specialized shearing teeth evolved before retractable claws. Furthermore, each derived character listed along the main trunk of the cladogram defines a clade. Hair, for example, is a defining character for the clade Mammalia. Retractable claws is a derived character shared only by the clade Felidae. Derived characters that occur “lower” on the cladogram than the branch point for a clade are not derived for that particular clade. Hair, for example, is not a derived character for the clade Carnivora.

In Your Notebook List the derived characters in Figure 18–9 and explain which groups in the cladogram have those characters.

End ofPage 519

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
Go to previous page Go to next page