Name:
Date:
Classification: How Is Life Organized?
Learning Outcomes:
1. Explain how the following principles are used in taxonomy to classify organisms:
a) Evolutionary relationships
b) Biochemical relationships
c) Homologous structures
d) Embryological relationships
2. Compare characteristics of a prokaryotic cell with those of a eukaryotic cell.
3. Describe the unifying characteristics of the following Domains of life:
a) Bacteria
b) Archaea
c) Eukarya
4. Classify organisms using the following taxons: Kingdom, phylum, sub-phylum, order, family,
genus and species.
5. Apply binomial nomenclature to classify organisms.
Text: 308 to 314; 4; 6-7. *This is required reading!
Biology 11: Classification
Page 1
Cells as a Basis for Classification
At a very basic level, organisms can be divided based on whether they
have cells or not. This will determine whether they are classified as
“living” or “non-living”.
-Viruses are not considered to be non-living as they are not made up of
a cell(s). Viruses are just protein capsules containing genetic material
(RNA or DNA).
-Cells are only found in living organisms and they represent the lowest
level of structure capable of performing all the activities required for
life (e.g. Able to respond to their environment, metabolism)
Living organisms are divided into two large groups depending on what type of cell(s) they have.
Name and describe the differences between the two:
a) ___________________________________________________________________________
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b) ___________________________________________________________________________
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Biology 11: Classification
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Label the main structures
highlighting the simularities
and differences between these
cell types.
Phylogeny and the Tree of
Life
Phylogenies Reflect Evolutionary Histories
A phylogeny is the evolutionary history of a species or group of species.
What type of evidence can be used to discover a species phylogeny?
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Biology 11: Classification
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Systematics Connects Classification with Phylogeny
Systematics is the branch of biology that classifies organisms and
determines their evolutionary relationships. This is also called “taxonomy”
Systematics groups organisms into categories which range from very
inclusive to very specific. Examine the diagram of a house cat’s
classification:
a) Which category (taxon) is most inclusive?
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b) Which taxon is least inclusive?
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c) What do each taxon represent?
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d) What is represented by the scientific name Felis catus?
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e) What is any easy way to remember the correct order of the
taxonomic categories?
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Phylogeny and classification are combined through the creation of a phylogenetic tree. Again,
this is hierarchical and becomes more inclusive as you move through it.
Phylogenetic Trees
Reconstructing a species’ evolutionary history involves sorting homologous from analogous
features and then infering phylogeny. Below are the steps involved in this process:
1. Cladistics:
-Common ancestry is used to group organisms into clades (ancestral species and its descendents,
monophyletic).
-Shared characteristic can be grouped two ways:
a) Shared ancestral characteristic
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Biology 11: Classification
Page 4
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b) Shared derived character
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2. Creating Phylogenies Using Shared Characteristics
-Shared characters can be organized into a Character Table that allows for a Phylogenetic Tree to
be created.
Two clades are used in this process:
a) Outgroup: ___________________________________________________________________
______________________________________________________________________________
b) Ingroup: ____________________________________________________________________
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Biology 11: Classification
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-Phylogenetic trees are organized based on the
idea of parsimony, that the simplest explanation
for observed phenomena are the best.
3. Molecular Systematics and Phylogenetic
Trees
-DNA and other molecular evidence can be used
to trace phylogeny (remember the Molecular
Connection assignment).
-DNA evidence is valuable as:
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Find 2 more phylogenetic trees in your textbook!
Pages? ________________________________________________Biology 11: Classification
Page 6
Constructing the Tree of Life
Domain is the largest classification taxa. What is evidence is used to determine to which domain
organisms belong?
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Below is an image of our current understanding of the phylogeny of the three domains of life.
Next to each of the images below, name and briefly describe the domain it represents. Text: 6-7.
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Biology 11: Classification
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http://www.youtube.com/watch?v=BQ1JaYxBH40&feature=fvw
Take your own notes to explain how the kingdoms of the Domain Eukarya are divided:
Kingdom
Uni/Multi Cellular?
Biology 11: Classification
Nutrition
Other Info
Page 8
Kingdom
Uni/Multi Cellular?
Nutrition
Other Info
Kingdom
Uni/Multi Cellular?
Nutrition
Other Info
Kingdom
Uni/Multi Cellular?
Nutrition
Other Info
Biology 11: Classification
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In the table below list the classification categories from the one with the largest number of
individuals to the smallest number and develop your own pneumonic to remember the order.
Fill in the classification of a striped skunk, cat and a wolf.
Fig. 15.15B will help you.
Categories
Striped Skunk
Wolf
Domestic cat
Domain
Kingdom
Biology 11: Classification
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