How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Resources
Chapter Presentation
Transparencies
Visual Concepts
Standardized Test Prep
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Classification of Organisms
Table of Contents
Section 1 Categories of Biological Classification
Section 2 How Biologists Classify Organisms
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Objectives
• Describe Linnaeus’s role in developing the modern
system of naming organisms.
• Summarize the scientific system for naming a
species.
• List the seven levels of biological classification.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Classification
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Taxonomy
• The science of naming and classifying organisms is
called taxonomy.
• Until the mid-1700s, biologists named a particular
type of organism by adding descriptive phrases to the
name of the genus.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Taxonomy, continued
A Simpler System
• A simpler system for naming organisms was
developed by the Swedish biologist Carl Linnaeus.
• Linnaeus’s two-word system for naming organisms is
called binomial nomenclature.
• Over the past 250 years since Linnaeus first used
two-part binomial species names, his approach has
been universally adopted.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Species Name
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Taxonomy, continued
Scientific Name
• The unique two-part name for a species is now
referred to as its scientific name.
• The first word is the genus to which the organism
belongs. A genus is a taxonomic category
containing similar species.
• The second word in a scientific name identifies
one particular kind of organism within the genus,
called a species. A species is the basic biological
unit in the Linnaean system of classification.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Classifying Organisms
• Linnaeus worked out a broad system of classification
for plants and animals in which an organism’s form
and structure are the basis for arranging specimens
in a collection.
• The genera and species that he described were later
organized into a ranked system of groups that
increase in inclusiveness.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Classifying Organisms, continued
• Similar genera are grouped into a family.
• Similar families are combined into an order.
• Orders with common properties are united in a class.
• Classes with similar characteristics are assigned to a
phylum.
• Similar phyla are collected into a kingdom.
• Similar kingdoms are grouped into domains.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Biological Hierarchy of Classification
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Linnaeus’s Levels of Classification
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Classification
Hierarchy of
Organisms
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Classifying Organisms, continued
Classification of the Honeybee
• Each level of classification is based on characteristics
shared by all the organisms it contains.
• The honeybee’s scientific name, Apis mellifera,
indicates that it belongs to the genus Apis, which is
classified in the family Apidae.
• All members of the family Apidae are bees that live
either alone or in hives, as does Apis mellifera.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 1 Categories of
Biological Classification
Classification of a Bee
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Objectives
• List the characteristics that biologists use to classify
organisms.
• Summarize the biological species concept.
• Relate analogous structures to convergent evolution.
• Describe how biologists use cladograms to
determine evolutionary histories.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
What Is a Species?
• In 1942, the biologist Ernst Mayr of Harvard
University proposed a biologically based definition of
species, which is called the biological species
concept.
• Mayr defined a biological species as a group of
natural populations that are interbreeding or that
could interbreed, and that are reproductively isolated
from other such groups.
• Sometimes individuals of different species interbreed
and produce offspring called hybrids.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Species
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
What Is a Species?, continued
Evaluating the Biological Species Concept
• The biological species concept works well for most
members of the kingdom Animalia, in which strong
barriers to hybridization usually exist.
• But the biological species concept fails to describe
species that reproduce asexually, such as all
species of bacteria and some species of protists,
fungi, plants, and even some animals.
• In practice, modern biologists recognize species
by studying an organism’s features.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
What Is a Species?, continued
Number of Species
• The number of species in the world is much greater
than the number described.
• Only about 1.5 million species have been described
to date.
• Scientists estimate that 5 million to 10 million more
species may live in the tropics alone.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Evolutionary History
• Classification based on similarities should reflect an
organism’s phylogeny, that is, its evolutionary
history.
• Through the process called convergent evolution,
similarities evolve in organisms not closely related to
one another, often because the organisms live in
similar habitats.
• Similarities that arise through convergent evolution
are called analogous characters.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Phylogeny
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Phylogenic Diagram of Mammals
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Comparing Convergent and Divergent
Evolution
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Analogous Features
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Evolutionary History, continued
Cladistics
• Cladistics is a method of analysis that reconstructs
phylogenies by inferring relationships based on
shared characters.
• With respect to two different groups, a character is
defined as an ancestral character if it evolved in a
common ancestor of both groups.
• A derived character evolved in an ancestor of one
group but not of the other.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Cladistics
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Evolutionary History, continued
Cladistics
• Cladistics is based on the principle that shared
derived characters provide evidence that two groups
are relatively closely related.
• A biologist using cladistics constructs a branching
diagram called a cladogram, which shows the
evolutionary relationships among groups of
organisms.
• Organisms that share derived characters, are
grouped together on the cladogram.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Cladograms
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Cladogram: Mammals, Reptiles, and Birds
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Cladogram: Major Groups of Plants
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Evolutionary History, continued
Considering Characters
• The great strength of cladistics is objectivity. If a
computer is fed the same set of data repeatedly, it
will make exactly the same cladogram every time.
• The disadvantage of cladistics is that the degree of
difference between organisms is not considered.
• Cladistic analysis does not take into account
variations in the “strength” of a character, such as
the size or location of a fin or the effectiveness of a
lung. Each character is treated equally.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Evolutionary History, continued
Evolutionary Systematics
• In evolutionary systematics, taxonomists give varying degrees
of importance to characters and thus produce a subjective
analysis of evolutionary relationships.
• In this type of analysis, evolutionary relationships are displayed
in a branching diagram called a phylogenic tree.
• Evolutionary systematics involves the full observational power of
the biologist, along with any biases he or she may have.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Evolutionary Systematics and Cladistic
Taxonomy
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Section 2 How Biologists
Classify Organisms
Systematics
Click below to watch the Visual Concept.
Visual Concept
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Standardized Test Prep
Multiple Choice
The diagram below shows seven levels of biological
classification from kingdom to species. Use the figure
below to answer questions 1–3.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Standardized Test Prep
Multiple Choice, continued
1. Which letter on the diagram represents the phylum
level of classification?
A.
B.
C.
D.
A
B
C
D
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Standardized Test Prep
Multiple Choice, continued
1. Which letter on the diagram represents the phylum
level of classification?
A.
B.
C.
D.
A
B
C
D
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Standardized Test Prep
Multiple Choice, continued
2. What level of classification does F represent?
F.
G.
H.
J.
class
family
genus
order
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Standardized Test Prep
Multiple Choice, continued
2. What level of classification does F represent?
F.
G.
H.
J.
class
family
genus
order
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Standardized Test Prep
Multiple Choice, continued
3. What can you infer about different species that
belong to the same group at level D?
A.
B.
C.
D.
They belong to the same group at level E.
They belong to different groups at level E.
They belong to the same group at level C.
They belong to different groups at level C.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 14
Standardized Test Prep
Multiple Choice, continued
3. What can you infer about different species that
belong to the same group at level D?
A.
B.
C.
D.
They belong to the same group at level E.
They belong to different groups at level E.
They belong to the same group at level C.
They belong to different groups at level C.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.