Download Background: Why Is Taxonomy Important?

Taxonomy
Biological Evolution and Classification
Background: Why Is Taxonomy Important?
Taxonomy is the system of classifying, or organizing, living organisms into a system based on their
similarities and differences. Imagine you are a scientist who studies bears, and you call
polar bears "white bears”. A scientist in another country studies those same bears, but calls them
"cream bears”. You are both talking about polar bears. However, since you are using different
common names, you may assume you were studying two distinctly different bear species. Now,
imagine if the millions of species of organisms were referred to by
their common names only!
In the late 1700s, a scientist named Carl Linnaeus invented a system of naming species known as
binomial nomenclature, an important part of taxonomy. This system uses Latin names to identify
the genus and species of an organism. In this system, both the genus and the species names are
italicized. The genus name is capitalized. The species name is lower case. This system significantly
helps scientists to identify which species they are referring to as it gives each species its own,
unique name.
For example, when this system is applied to bears, scientists know that when they see the name
Ursus maritimus, they are referring to a "Bear polar", or polar bear. If the scientist named Ursus
arctos, then she would be referring to a brown bear. If the scientist named Ursus arctos horribilis (a
trinomial name that further categorizes the species into subspecies), then she would be referring to
a grizzly bear. As you can imagine, these are very important distinctions as all three of these bears
share the same habitat, and some even have the same coloring.
Since Linnaeus devised his taxonomic system in 1758, this original system has changed as
scientists apply new technologies, discover new species, and obtain other types of new knowledge
about living organisms. This is due (in part) to ever-improving technologies that work at the
molecular level. For example, modern genetic research indicates that physical features, or
phenotypes, may be misleading when trying to determine relatedness.
Please complete the Background section in your Student Journal.
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Taxonomy
Biological Evolution and Classification
Part I: Similarities and Differences
Procedure:
1.  Examine Organisms A and B shown below. Look at each image carefully.
Organism A
Organism B
2.  How are these organisms similar? Use the photos and what you may already know about these
types of organisms to make a list. Think of the similarities in terms of body structure, where
these organisms live (habitat), reproductive and life cycles, and requirements for life. Be as
specific as you can.
3.  How are these organisms different? Again, use the photos and what you know to make a list.
What are the obvious differences? Could the differences be due to habitat, diet, predation,
reproduction, or perhaps some other factor? Be as specific as you can.
4.  Once you have completed your observations and made your lists, use the Venn diagram
provided in Part 1 of your Student Journal to categorize the similarities and differences in the
phenotypes of the two organisms.
5.  Once you have completed your Venn diagram, describe how this information could help you to
categorize these two organisms. Also, list one distinguishing feature that you observed and
how that feature would help you distinguish between these two organisms.
Complete Part I in your Student Journal.
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Taxonomy
Biological Evolution and Classification
Part II: Surprise! Categorize!
Procedures:
1.  The characteristics of leaves are often used to identify trees. Obtain the Leaf Sort Cards. Lay
them out on the table and examine the characteristics of each leaf.
2.  Sort the leaf cards into categories based on their characteristics. Give a name to each of these
categories in the space provided in your Student Journal.
3.  Next, use the available classroom supply items provided in your room. You will sort these items
by category.
4.  Start by sorting the items into larger groups. These could be considered functional groups, or
items that perform similar functions. Give each functional group a name.
5.  Then, sort those items further into smaller groups. You may choose any grouping strategy that
you like. However, make sure that you describe your process and why you grouped the items in
the way that you did. Each of these smaller categories should also have a name.
6.  Create a flow chart in the space provided in your Student Journal. As you sort each item into
progressively smaller groups, give each group a descriptive name in your flow chart. You may
use a flow chart similar to the one shown on this page. Keep in mind that your particular flow
chart will contain more components and will look different.
Classroom
Supplies
Fasteners
Metal
Sharp
Tack
Complete Part II in your Student Journal.
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Taxonomy
Biological Evolution and Classification
Part III: Kingdom Comparison
Procedure:
1.  Review the information below about the six currently recognized Kingdoms of organisms.
2.  Organize the information in Part III of your Student Journal by completing the table.
Kingdom Plantae
Plants are autotrophic, eukaryotic, multicellular organisms.
They are sessile and can reproduce sexually or asexually.
Kingdom Fungi
Fungi are eukaryotic, heterotrophic, single-celled or multicellular
organisms. Most of them are sessile and can reproduce sexually or
asexually.
Kingdom Bacteria
Bacteria are unicellular, prokaryotic organisms that are motile,
heterotrophic or autotrophic, and reproduce through cell division.
Kingdom Animalia
Animals are eukaryotic, heterotrophic, multicellular organisms.
They are motile and most commonly reproduce sexually.
Kingdom Protista
Protists are mostly uniceulllar, eukaryotic, heterotrophic or
autotrophic organisms that primarily reproduce asexually.
Kingdom Archaea
Archaea are unicellular prokaryotic organisms that can be
heterotrophic or autotrophic and reproduce asexually.
Complete questions 1-3 in Part III in your Student Journal.
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Taxonomy
Biological Evolution and Classification
Part III: Kingdom Comparison, continued
Cladistics is the science of classifying organisms based on their relatedness. This science shows
common descent, ancestor, and evolutionary lineage of organisms. Before DNA and chromosomal
analysis, cladistics used mostly anatomical or molecular characteristics to show lineage. As
technology allows us to determine the make-up of individual organism's DNA, we are better able to
see common ancestry.
A cladogram is a diagram used to show ancestral relationships. The branching design depicts the
points at which different species diverge from a common ancestor.
Example 1
Example 2
Complete Part III and the remainder of your Student Journal.
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