Unit
Diversity of Living Things
1
Chapter 1: Understanding Biodiversity
The variety of life forms on Earth is called biodiversity, comprising species diversity,
genetic diversity, structural diversity, and individual variability. All species are dependent in a variety of ways on this diversity. All organisms are classified into different
groups based on physical and evolutionary characteristics, making it easier for scientists to study and define, and to share knowledge with one another. Biodiversity also
encompasses the diversity in ecosystems: diversity of habitats and interactions. Loss
of biodiversity threatens the health of ecosystems and thus the survival of all species.
Chapter 2: The Prokaryotes, Viruses, and Protists
Big ideas
• All living things can be classified
according to their anatomical and
physiological characteristics.
• Human activities affect the
diversity of living things in
ecosystems.
Prokaryotes, viruses, and protists are the most abundant organisms on Earth and
they are not visible to the unaided human eye. Prokaryotes include all the organisms
in the Kingdoms and Domains Eubacteria (Bacteria) and Archaea. Bacteria play key
roles as decomposers and pathogens, and in the production of foods and medications.
Archaea live in extreme conditions, but little else is known about them.
Viruses are responsible for many human diseases ranging from the common cold
and chicken pox to AIDS, cholera, and rabies. Many viruses are harmful, but they are
important in ecosystems as a means of population control. They may also be used in
gene therapy to deliver drugs or genes to cells.
The smallest eukaryotes and some of the largest belong to the Kingdom Protista,
including all eukaryotes other than fungi, plants, or animals. Protists play key roles in
aquatic ecosystems. As a result of this extreme diversity, there is no “typical” protist.
Protists exhibit a wide variety of cell features, different ways of moving (if they move
at all), different ways of getting nutrients and energy, and very different methods of
reproducing.
Chapter 3: The Fungi, Plants, and Animals
Fungi, plants, and animals are organisms that have adapted to living in the
variable and challenging conditions of terrestrial ecosystems. Adaptations include
mechanisms for dealing with changes in temperature, loss of water, and the need to
support their own mass. They have also adapted to life on land with each other and
have established many relationships: producer and consumer, predator and prey,
and symbiotic relationships.
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Unit 1 • Overview 1
1.1
Textbook pp. 8–13
Biodiversity—An Introduction
Main idea: The biological species concept defines species as a population of individuals
that are able to freely breed under natural conditions. Biologists have identified and
described more than 1.7 million species.
1. Would you expect that bald eagles and red-tailed hawks would be able to breed
with each other? Explain. T / I
2. Which two types of organisms are exceptions to the biological species concept?
Explain why. T / I
Main idea: All species depend on other species in a variety of ways for their
own survival.
3. Create a flowchart in the space below that shows the direction in which energy
from food flows through the following organisms: heterotrophs, micro-organisms,
autotrophs. Label each step in the process. K/U C
4. Fill in Table 1 with an example of each type of species interaction.
K/U
Table 1 Interactions Between Species
Interaction
Example
Food supply
Protection
Transportation
Reproduction
Hygiene
Digestion
2 Unit 1 • Diversity of Living Things
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Main idea: Biodiversity refers to the variety of species in an ecosystem but also includes
structural diversity within ecosystems and individual variability within species.
5. Complete Table 2 to compare different types of biodiversity. T / I
Table 2 Three Types of Biodiversity
Type of Biodiversity
Description and Example
genetic diversity
species diversity
Study Tip
A diverting activity?
The word diverge means “to go
in different directions.” The word
diversity, which means variety,
comes from the same Latin words
and has a related meaning in the
terms biodiversity, species diversity,
genetic diversity, and structural
diversity. Look for other words that
use the Latin roots prefix dis- and the
root verge- and learn their definitions.
structural diversity
6. A plantation of white pine trees that are all the same age is sure to be lacking
which two types of biodiversity? Explain why. T / I
Main idea: Species evolve over time and space.
7. In your own words, explain what is meant by the statement “Species evolve
over time and space.” K/U T / I
8. The physical and behavioural changes that occur in an entire population of a
species over time are called
. K/U
Main idea: Although new species are still being discovered, biodiversity is under threat
from many human activities.
9. In your own words, explain how today’s high rate of species extinctions is
different from previous mass extinctions. K/U
10. List four ways that the loss of biodiversity affects humans and other species.
K/U
(i)
(ii)
(iii)
(iv)
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1.1 Biodiversity—An Introduction 3
1.2
Textbook pp. 14–20
The Nature of Classification
Vocabulary
biological classification
botanist
binomial nomenclature
kingdom
taxonomy
genus
taxon
dichotomous key
Main idea: Classification systems are useful, but extremely variable.
1. In your own words, write a definition for biological classification.
K/U
2. Give an example of an organism that fills each of the following ecosystem
roles. K/U
(a) producer:
(b) herbivore:
(c) carnivore:
(d) scavenger:
Main idea: The science of classifying living things is called taxonomy.
3. What is another term for taxonomy?
. K/U
4. In Table 1 below, list three types of observed characteristics that help biologists
identify organisms and an example of each characteristic. K/U
Table 1 Observed Characteristics
Types of observed characteristics
Examples
5. Fill in the Venn diagram below to show the similarities and differences
between Siamese cats and poodles. K/U A
Siamese cats
4 Unit 1 • Diversity of Living Things
Poodles
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6. List three challenges that make identifying species challenging.
T / I
Main idea: Traditional taxonomy groups species together according to shared
characteristics.
7. Carl Linnaeus is considered the “father” of taxonomy. What did he introduce
to the science of classification? K/U
8. Carl Linnaeus considered species to be types of living things that could be
grouped into
according to shared characteristics.
K/U
Main idea: All species are given a unique binomial (two-word) species name.
9. What is the formal system now used to name species? K/U
10. In the name Ursus maritimus,
is the genus name, and
is the species name. T / I
11. Of Ursus maritimus, Ursus americanus, and Numenius americanus, which two
species are most closely related? Explain how you can tell. T / I
Main idea: Traditional taxonomy groups species into a number of major levels, or taxa.
Scientists often disagree about the criteria used to group species.
12. In the Linnaean system, each taxon consists of species that have similar
features. Provide two characteristics that only organisms in class Mammalia
possess. K/U T / I
13. Based on traditional taxonomy and information in the text, fill in the blanks in
Table 2 below. K/U T / I
Table 2 Human and Honey Bee Taxa Names
Taxon
Human
Honey Bee
Animalia
Animalia
Mammalia
Insecta
Primates
Hymenoptera
Hominidae
Apidae
Homo sapiens
Apis mellifera
Learning Tip
Naming Species
The first word of a binomial species
name is always capitalized. The
second word is always lowercase.
Both words are printed in italics.
The names of other taxonomic
levels are normally capitalized.
Binomial species names can also
be abbreviated. For example, Homo
sapiens can be written H. sapiens.
Study Tip
Taxa Mnemonic Devices
A common mnemonic device for
remembering the order of the
traditional taxa from least to most
specific is “King Philip came over from
Germany stunned” (Kingdom Phylum
Class Order Family Genus Species).
Try to come up with your own.
phylum
genus
species (binomial)
14. What issue do scientists often disagree about when they are trying to classify
species? K/U
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1.2 The Nature of Classification 5
MAin iDeA: Dichotomous keys are often used to help identify species.
15. Briefly explain how to use a dichotomous key to identify an organism.
K/U
16. Complete the following dichotomous keys using the bird illustrations below.
T/i
C
A
bill strongly curved........................................................... (a)
bill elongated
bill uniform in width................... (b)
bill straight
bill greatly widened at end.......... (c)
bill straight..................................................................... (d)
bill not elongated
bill strongly hooked.......................................................... (e)
spoonbill
6
Unit 1 • Diversity of Living Things
heron
ibis
eagle
cardinal
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1.3
Phylogeny and Modern Taxonomy
Vocabulary
evolution
phylogeny
phylogenetic tree
Textbook pp. 21–25
clade
MAin iDeA: Modern biological classification is based on phylogeny, which is the
evolutionary relatedness of species.
1. In your own words, describe the theory of evolution. K/U C
2. How is phylogeny different from the relationships shown in a family tree?
STUDy TiP
The “Phyl-” Family
The root word of both phylum and
phylogeny comes from the Greek
root “phyl-,” or “tribe.” Look for other
scientific words that use this root
word.
T/i
MAin iDeA: Phylogenetic trees are used to show evolutionary relationships among
species and groups.
3. What do the individuals in a family tree have in common with the groups of
organisms in a phylogenetic tree? T / i
4. What types of evidence support the relationships shown in phylogenetic
trees? K/U
5. In Figure 1, label the top and bottom of the arrow at the right of the
phylogenetic tree to represent the passage of time. K / i
rhinoceros horse
zebra
Figure 1
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1.3 Phylogeny and Modern Taxonomy
7
MAin iDeA: A clade is a taxonomic group that includes all the descendants of a common
ancestor.
Use Figure 2 below to answer questions 6 to 8.
Figure 2
6. How many clades are shown in Figure 2 above? Which of the animals belong
to each of the clade(s)? T / i
7. What part of Figure 2 above represents the common ancestor of all of the
animals? T / i
8. In Figure 2, do the gull and the fox form a clade? Explain why or why not.
T/i
MAin iDeA: Both traditional and phylogenetic classification systems have advantages
and disadvantages.
9. Fill in Table 1 below with the advantages and disadvantages of traditional and
phylogenetic classification. T / i
Table 1 Classification Advantages and Disadvantages
Advantages
Disadvantages
Traditional
classification
Phylogenetic
analysis
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Unit 1 • Diversity of Living Things
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1.4
Kingdoms and Domains
Vocabulary
prokaryote
eukaryote
Textbook pp. 26–29
domain
Main idea: Most biologists classify living things using a system of six kingdoms and
three domains.
1. Match the organisms on the left with their correct definition on the right. K/U
(a) prokaryotes
(i)unicellular and small multicellular organisms with
organelles
(b) eukaryotes (ii)organisms that have organelles but that are not
fungi, plants, or animals
(c) protists (iii)unicellular organisms without membrane-bound
organelles
2. Are pine trees prokaryotes or eukaryotes? Explain. T / I
3. Complete the tree diagram below to show how the three domains relate to the
six kingdoms of life. T / I
All organisms
Domain Eubacteria
Domain
Kingdom
Kingdom Archaea
Learning Tip
Name Change
Archaea used to be called
Archaebacteria, but we now know
that they are distinct from Eubacteria,
the “true bacteria.”
Domain
Kingdom
Kingdom
Kingdom Plants
Kingdom
4. Your classmate states that some animals are prokaryotes. Do you agree or
disagree? Explain. T / I C
Study Tip
Main idea: The most easily recognized kingdoms of life are Animals, Plants, and Fungi.
Eubacteria and Archaea are the most difficult to distinguish.
5. What is one reason why we most easily recognize organisms that belong to the
fungi, plant, and animal kingdoms? T / I
6. Are Eubacteria and Archaea prokaryotes or eukaryotes? Explain.
7. Eubacteria are commonly called
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.
K/U
K/U
Rhyming Helps
You can distinguish Archaea and
Eubacteria easily for yourself by
remember the rhyming phrase
“Eubacteria are true bacteria.” In
fact, many scientists do not consider
Archaea bacteria, so they simply call
the domain Eubacteria Bacteria. Come
up with other rhyming phrases that can
help you remember scientific facts.
1.4 Kingdoms and Domains 9
8. Most prokaryotes consist of
cells, but some others consist of
K/U
Main idea: Protista is the only kingdom that does not represent a clade.
9. Give two examples of protist characteristics that demonstrate their diversity.
10. Give two reasons why protists are not considered a clade.
K/U
K/U
Main idea: The six-kingdom, three-domain system is based on phylogenetic
relationships revealed by genetic evidence.
Use Figure 1 below to answer Questions 11 to 13.
um
aea
ch
r
a
lo
ha
thermotogales
mi
cr
os
po
ri
animals
ulds
e mo
slim
ae
eb
mo
ba
me
cte
tha
riu
no
m
co
cc
us
ta
en
dic
ti
na
rci
sa
no
tha
flavobacteria
pyr
o
an
o
me
ria
eth
s
teu
p ro
rmo
t he
ria
ives
cyano
bacte
posit
eb
ac
te
m
green nonsulfur bacteria
gram
pu
rpl
Eukaryotes
Archaea
Eubacteria
gi
fun
cilia
t
dia
plants
es
flagella
tes
trich
omon
ads
dipl
om
ona
ds
Most recent common ancestor
of all living organisms
Figure 1 Domain diagram
11. Judging from the evolutionary relationships shown in the diagram of the
domains of life (Figure 1), are eukaryotes more closely related to Archaea or
Eubacteria? Explain. C A
12. Why are animals, plants, and fungi so close together on the rightmost tree in
the domain diagram above (Figure 1)? T / I
13. Do you think the domain diagram could change? Explain.
10 Unit 1 • Diversity of Living Things
T / I
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Biology JOURNAL
1.5
Birds—in a Class of Their own
Textbook pp. 30–31
MAin iDeA: Phylogenetic classification of organisms has revealed some surprising
relationships. More will likely emerge as research and debate continue.
Use Figure 1 below to answer questions 1 to 3.
A
Class
Aves
dinosaurs
crocodilians
lizards and snakes
turtles
Class
Reptilia
birds
Class
Mammalia
mammals
amphibians
Class
Amphibia
common ancestor
of all reptiles
Figure 1 Phylogenetic tree showing traditional taxonomy
1. According to the Class names in Figure 1 above, are reptiles and birds in the
same class? Explain. T / i
2. According to Figure 1, are birds more closely related to dinosaurs or to
crocodilians? Explain. T / i
LeArNINg TiP
Taxa Names
The name of the traditional
taxonomic class for birds, “Aves,”
is adapted from the Latin word for
bird, “avis.”
3. According to Figure 1, the crocodile group of reptiles is more closely related to
birds than to other reptiles. Should crocodilians be considered reptiles if they
are genetically more closely related to birds than to other reptiles? If so, should
birds also be considered reptiles? Explain your answers. T / i C A
4. Suppose you were revising this textbook in the year 2025. How many of the
phylogenetic tree illustrations in this chapter would you expect to have to
revise? Most? A few? None? Explain your answer. C A
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1.5 Biology Journal: Birds—In a Class of Their Own
11
CHAPTER
1 Summary
Understanding Biodiversity
is evaluated by
Biodiversity
includes
biological classification
such as
genetic
diversity
species
diversity
which result from
structural
diversity
dichotomous
key
traditional
taxonomy
organized by
hybridization
evolutionary
change
phylogeny
results in
determination of
taxa
clade
including
kingdom, phylum,
class, order, family,
genus, species
shown by
phylogenetic
tree
resulting in
kingdoms
of life
12 Unit 1 • Diversity of Living Things
binomial
nomenclature
(genus & species)
domains
of life
including
including
eubacteria,
archaea, protists,
fungi, plants,
animals
eubacteria,
archaea,
eukaryotes
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Chapter
1 Questions
1. Two plants that appear to be different species will sometimes breed with each
other. What is this process called? (1.1) K/U
(a) morphology
(b) biodiversity
(c) genetic diversity
(d) hybridization
2. Clades are based on the most fundamental connection between species: their
(a) evolutionary relatedness
(b) morphology
(c) taxon
(d) domain (1.3) K/U
3. Indicate whether each statement is true or false. If you think the statement is
false, rewrite it to make it true.
(a) Carl Woese concluded that all organisms could be classified into six
kingdoms based on differences in genetic makeup. (1.4) K/U
(b) Most scientists consider birds to be a group of living dinosaurs. (1.5)
4. Complete Table 1 below with details about the six kingdoms of life. (1.4)
K/U
T / I
C
A
Knowledge/Understanding
Thinking/Investigation
Communication
Application
K/U
T / I
Table 1 Kingdoms of Life
Kingdom
Prokaryotic or
eukaryotic?
Number of cells
Example
Eubacteria
prokaryotic
unicellular
Salmonella
Archaea
Protista
Fungi
Plants
Animals
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Chapter 1 Questions 13
5. Explain why the creation of an accurate biological classification system for
plants was necessary to ensure human health and success. (1.2) C A
6. Is morphology more important to traditional taxonomy or to phylogeny?
Explain. (1.1, 1.2, 1.3) A
7. Fill in the Venn diagram below to compare birds and crocodilian reptiles. (1.5)
Birds
A
Crocodilian Reptiles
8. Complete the bubble map below to show six properties of plants. (1.3)
A
reproduce
sexually;
sometimes
asexually
Plants
cell walls
composed
of cellulose
9. Suppose your lab partner suggested that you attempt to classify a prokaryote
using the biological species concept. How would you respond? Explain.
(1.1, 1.3) A
14 Unit 1 • Diversity of Living Things
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