Biology Lab Shahimermaid
wenell
lab_6biol102lab_manual2013-2.pdf
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Kingdoms
Lab 6 Taxonomy
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Lab 6: Taxonomy
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Introduc on
Taxonomy is the science of iden fying and naming organisms into related groups, a process called clas si ca on. Originally, taxonomic classi ca on of organisms was based solely on structural and physio logical similari es. However, advanced technologies and informa on has allowed scien sts to specify taxonomic classi ca on using gene c informa on (phylogene c similari es) as well.
Over me, many di erent classi ca on systems have been developed. Although many of them are sig ni cant, one of the most widely accepted system is called the Linnaean system. Carl Linnaeus devel oped the Linnaean system in 1735. This system uses La n because, at the me, it was a language used by most of the scien c world. Although many of the exact terms set forth by Linneaus have been sub s tuted, the Linnaean system is s ll respected by many scien sts as the fundamental taxonomic sys tem.
The Linnaean system begins by assuming assumes that there are three kingdoms; the animal kingdom, the plant kingdom, and the mineral kingdom (which has since been abandoned). Since the Linnean sys tem was established, various life forms have been added to new kingdoms: Monera (for prokaryotes), Pro sta (for pro sts and most algae), and Fungi. These ve kingdoms are s ll far from ideal, and con nue to evolve as scien sts learn more knowledge of genomes con nues to advance. Modern taxono
mists have also supplanted these categories by forming domains, the highest taxonomic ranking. The three domains that are used are: Bacteria, Archaea, and Eukaryota. Each of the kingdoms listed above are further divided into classes, orders, families, genera, and species.
Linnaeus also popularized the use of binomial nomenclature. Binomial nomenclature is the formal naming system used for all living organisms. Every organism is iden ed with a two part name. The rst name signi es the genus that the species belongs to, and the second name signi es the species
within the genus. Prior to this nomenclature, animals were classi ed based on how they moved.
The speci city of the organism increases it is classi ed into smaller, more narrow categories (Figure 1). In other words, the categories get smaller in terms of the number of organisms that are included, with the smallest widely accepted category being “sub species”.
Concepts to explore:
Taxonomy Linnaean system Binomial nomenclature Taxonomic vs. phylogene c classi ca ons
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It is important to remember that taxonomy is highly dependent on biology, par cularly anatomy and physiology. In fact, one of many, but the most widely accepted de ni on of a species is that its members can interbreed and create viable o spring. For exam ple, it is physiologically possible for a lion and a gress to interbreed. However, because their o spring (a liger) is sterile, it is not considered a viable o spring. Therefore, lions and gers are not consid ered the same species. However, a Labrador Re triever and poodle can produce o spring that are not sterile (the o spring is commonly called a labra doodle). Thus they are considered the same species. Remember, this is just one method of de ning a spe cies. There are many other tools and de ni ons that can be used to determine what organisms belong to which species groups.
Looking at Figure 1, imagine you are standing at the bo om of a large tree with many branches. While on the ground you can see the whole tree (the trunk, large branches and small branches), but as you begin to climb up the tree you can no longer see the whole tree, only the smaller branches. It’s the same concept for classi ca on. Star ng at the “bo om” (or the domain) many organisms are includ ed, but as you move “up” the classi ca on system, more are excluded and fewer remain. Table 1 illus trates how you would classify a human being and a red maple tree.
Table 1: Classi ca on of humans and a red maple tree
As illustrated in Figure 1, the Linnaean system classi es organisms into sequen al groups:
Domain Kingdom
Example: Human Being Red Maple
Domain Eukarya Eukarya
Kingdom Animalia Plantae
Phylum Chordata Tracheophyta
Class Mammalia Angiospermae
Order Primates Sapindales
Family Hominidae Acerceae
Genus Homo Acer Species Sapien Acer rubrum
Figure 1: Taxonomy Tree. To use this tree, one would begin at the bo om and work up.
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Phylum Class Order Family Genus Species
Sub species are used in some classi ca ons and is generally well accepted, but not always included in the Linnaean system.
A useful tool to remembering the order of the Linnaean classi ca on system is developed by crea ng a mnemonic phrase using the rst le er of each classi ca on. For example: Daring Kids Pick Cauli ower Over Fresh Grown Strawberries.
Experiment 1: Classi ca on of common objects
In this exercise, we will take common objects and group them into “taxonomic” categories.
Procedure
1. Spread the materials out on the table.
2. Use the ow chart (Figure 2; located in the back of this lab) to classify the objects. Answer the ques ons for each object and place them in the proper groups. Fill in all the boxes along the way. If the box says “ok” in it, only one object ts in this category. Next to that box, write the object that is being described.
Make your own mnemonic phrase: _______________________________________
Materials
Pencil* Permanent Marker Marble Bead (hole in the center) Ruler Straw
Washer Hexagonal nut Bu on Figure 2 ( ow chart) at the end of the lab *You must provide
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Ques ons
1. Did you nd that the items grouped together as you worked down the ow chart had similar char acteris cs in terms of their appearance? What about func on?
2. Do you feel that the ques ons asked were appropriate? What ques ons would you have asked? What objects would be grouped together with your system?
3. Pick 10 household items (e.g. spoon, book, paper clip, etc.) and design a taxonomic classi ca on system to categorize them, similar to the one in Figure 2.
4. Can you devise a di erent classi ca on system for the objects used in this experiment that would dis nguish each in as many, or fewer steps?
Experiment 2: Classi ca on of organisms
Materials
Use Table 2 below as well as the “tree” (Figure 3) a ached at the end of the lab.
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Table 2: Key characteris cs of some organisms
Procedure
1. Select the rst organism from Table 2 (E. coli).
2. Use the “tree” (Figure 3; located at the back of this lab) start at the base, and answer each ques on un l the organism reaches the end of a “branch”. Write the organisms name in the green box.
3. Repeat this for the remaining organisms.
4. A er classi ca on, ll in Table 2 with the correct kingdom for each organism.
Ques ons
1. Did this series of ques ons correctly organize each organism? Why or why not?
2. What addi onal ques ons would you ask to further categorize the items within the kingdoms (hint: think about other organisms in the kingdom and what makes them di erent than the examples used here)?
3. Do you feel that the ques ons asked were appropriate? What ques ons would you have asked?
Organism Kingdom De ned Nucleus Mobile Cell Wall Photosynthesis Unicellular
E. coli
Protozoa
Mushroom
Sun ower
Bear
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Is the object cylindrical or round?
Yes
Figure 2: Experiment 1: Classi ca on of Common Objects Flow Chart
Start
1.
Is the object used for wri ng?
Is there permanent ink on the object?
Is the object metal?
Is there a hole in or near the center of the object?
No
Yes
Is the object smooth on the outside (no angles)?
Yes
No
2.
Yes No
Yes
Yes
3.
Yes No
Yes
4. 5.
Yes No
Yes 6.
No
Is the object longer than 5 cm?
7.
Yes No Does the object
have more than one hole? 8.
9.
No
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Figure 3: Experiment 2: Classi ca on of Organisms Flow Chart
Start
Does the organism have a de ned nucleus?
Does the organism perform
photosynthesis?
Is the organism mobile?
Kingdom:
Plant
Kingdom:
Fungi
Yes
No
Does the organism have a cell wall?
Kingdom:
Animal
Yes No
Kingdom:
Pro st
Kingdom: Bacteria
Yes No
Yes No
