Lessons ALIVE: Engaging Learners with Video
ALIVE!
ons
How Do You
Name MILLIONS
s
s
e
L
of Arthropods?:
Applying Taxonomy
Grades 5–7
Using AIT Products
■ The Shape of Life, episode 6, “Arthropods: The Conquerors”
■ Life on Our Planet, program 3, “Insects, Insects, Insects”
■ The Shape of Life, episode 2, “Cnidarians: Behavior on the Move”
Overview
Taxonomy is the study or science of naming and
grouping organisms. Common names are generally used in everyday conversation, but they do
not positively identify a particular species, due
to many organisms having more than one common name. This lesson will focus on the taxonomy of animals, specifically the group of animals
known as arthropods.
Of the 1.25 million animals that have been identified on Earth, more than a million of them are
arthropods. The incredible diversity and success
of the arthropods, including lobsters, spiders,
centipedes, and all insects, can be attributed to
their extraordinarily adaptable body plan. A key
feature is the evolution of the myriad types of
appendages (antennae, claws, wings, shields,
mouth parts) that allow arthropods to exploit
nearly every niche on Earth.
In this lesson, students will learn about the science of taxonomy, and apply the principles of
taxonomy to categorizing the various species of
arthropods. They will explore the task of organizing animals using dichotomous keys and the
hierarchy of taxonomy, and then try their hand
at creating, categorizing, and naming a “new”
arthropod species.
Objectives
• Explore similarities that reflect the body plans
of organisms, and how these similarities serve
as the basis for a classification hierarchy of
groups and subgroups.
• Investigate and understand the distinguishing
characteristics of major animal Phyla, specifically arthropods, and the characteristics of
some of the arthropod species.
• Describe how environmental conditions affect
the development of body plans in organisms.
• Examine the contributions to taxonomy made
by Carolus Linnaeus.
Agency for Instructional Technology • www.ait.net
1
Lessons ALIVE: Engaging Learners with Video
• Analyze and create dichotomous keys to identify unknown organisms and objects.
• Glue or tape
• Paint or markers
• Explore the binomial naming convention
used by taxonomists.
• Create a model of a “new” (imaginary) species
of arthropod and create a taxonomic hierarchy that reflects its relationship to similar
organisms.
Vocabulary
body plan
class
classification
dichotomous key
family
genus
hierarchy
Kingdom
mnemonic device
order
Phylum
species
taxonomists
taxonomy
Preparation
Materials Needed
• The Shape of Life, episode 6, “Arthropods: The
Conquerors”—Cue the tape to approximate
time code 4:43 (about 6.5 minutes in length).
• Worksheet, Dichotomous Keys: Identify the
Aliens!—One copy for each student.
• Mnemonic poster, Kings Play Chess on FineGrained Sand (see Planning Notes, in Col. 2)
• AIT video Life on Our Planet, program 3,
“Insects, Insects, Insects”—Cue the tape to
approximate time code 1:13 (about 1.4 minutes in length).
• The Shape of Life, episode 2, “Cnidarians:
Behavior on the Move”—Cue the tape to
approximate time code 18:12 (about 10 minutes in length).
• Scissors
• Large selection of assorted craft items (see
Planning Notes, below)
Planning Notes
• The Group Work activity for Day Two of this
lesson requires students or groups to create a
new species of animal. Several weeks before
the lesson ask students to bring in disposable
or recyclable items from home that may be
used in the activity. Create a “wish list” for
students to take home. Some items you might
ask for:
cereal boxes
shoe boxes
paper-towel tubes
toilet-paper tubes
drinking straws
pipe cleaners
newspapers
magazines
tissue paper
gift-wrap paper
new or used pencils
chopsticks
facial-tissue boxes
cans (any size)
gift-wrap tubes
cardboard
chenille stems
yarn or string
catalogs
maps
paper sacks
plastic lids
twigs or branches
rubber bands
styrofoam (any size or shape)
• A mnemonic illustration is provided in two
versions for your use during the Previewing
Activity on Day Two. You might want to post
or project the full-color PDF version in the
classroom, or enlarge, duplicate, and pass out
copies of the line drawing for students to
keep.
Time
This project will take about three 45-minute
class periods, in addition to homework and
extension activity time.
• Colored construction paper
2
Agency for Instructional Technology • www.ait.net
Lessons ALIVE: Engaging Learners with Video
Procedure—Day 1
Introduce Topic: Categorizing Animals
Take two or three minutes and ask students to
call out as many different “bugs” or “creepy
crawlies” that they can think of while you list
them on the board. After the time is up, ask students to help you sort the creatures into categories. Don’t try to guide students in their
grouping characteristics; this should be a free
brainstorming activity. (If students are slow to
understand the concept, you might give them
prompts, such as asking how they might sort the
bugs: by color, size, number of legs, what they
eat, etc.)
Ask the class to brainstorm titles or headings for
each of the categories. They can be as creative as
they like in their names, using made-up words if
they like.
Begin the video segment at about time code
4:43, right after the scientist holds up the fossil
and the narrator says, “. . . Braddy wonders who
first developed this radical design.” PAUSE the
video at the on-screen question, “How many
uses of arthropod appendages can you name?”
to allow students to discuss the answer.
(ANSWER: Individual appendages may be modified into sensory antennae, mouthparts of various kinds, legs, reproductive appendages,
grasping arms, shields, or even perhaps wings.)
Continue PLAY to approximate time code 11:03,
when the Swiss Army knife “flies” away. After the
video, go back to students’ predictions of the
arthropod body plan and allow them to make
changes until you have a simple list of the most
obvious parts of the arthropod body plan:
1. An exoskeleton (that is occasionally shed for
the animal to grow)
Briefly discuss the categories created. Were any
characteristics based on senses other than sight?
Why were most characteristics the types you can
see, rather than hear, smell, or touch?
2. Jointed appendages (that can be modified to
create legs, claws, antennae, or wings)
Explain that when scientists group animals into
categories, they often rely on sight, too.
Scientists group animals by the differences in
their body plans. To learn how an animal’s body
plan gives scientists clues in grouping and identifying them, students will be focusing on some
creatures that share the same body plan. Those
creatures are called arthropods. Write the word
“arthropods” on the board.
Class Activity: Dichotomous Keys
Video
Prepare students for watching a clip from AIT’s
video Shape of Life, “Arthropods: The
Conquerors” by asking them to describe how the
“bugs” they categorized in the first activity are
alike—what are some features of the body plan?
List any suggestions on the board, and tell students to keep those items in mind as they watch
the video.
3. A segmented body
Explain that, once scientists have identified the
unique characteristics of a group’s body plan, it
is fairly simple for them to sort animals into
groups and identify them by looking at the different variations of this plan. To help them in
this sorting, they use a tool called a dichotomous
key. The word “dichotomous” (pronounced dyeKOT-uh-mus) means “divided into two
branches.” A dichotomous key consists of groups
of statements or questions that describe one
aspect of an organism. Every organism will fit
one of the choices.
At each step of the process, the user is given a
characteristic with two choices. Each choice
leads to another characteristic with two choices,
and so on, narrowing the field, until a final
choice leads to the specific organism being
Agency for Instructional Technology • www.ait.net
3
Lessons ALIVE: Engaging Learners with Video
studied. For example, a dichotomous key used in
identifying birds might include a choice between
“eyes facing forward” or “eyes facing out to the
side.”
Pass out the worksheet Dichotomous Keys:
Identify the Aliens! and allow students 10 to 15
minutes to complete the activity. If you have
time, have students trade papers and go through
the key as a class.
Homework
Have students collect five different but similar
objects from their homes (such as leaves from
five different trees, flowers, rocks, sea shells, buttons, tools, and so on) and create a worksheet
like the alien activity, including a dichotomous
key that will help others sort the objects. Have
students keep the following instructions in mind
as they create the branches of the key:
• Each branch should give the user only two
choices.
through each other’s dichotomous keys. Briefly
discuss how dichotomous keys can be used to
sort organisms or other objects. What did students consider the easiest part of the activity?
What was the most difficult? How might some of
the keys be corrected or improved upon?
Introduce New Topic: Naming Animals
In order to study animals (and plants), all scientists need to use the same names. Using the
same names keeps scientists from getting confused when they discuss or read about each
other’s work. For example, what do you know
about the following animals: puma, cougar,
mountain lion, and panther? These are all occasionally used by different people as names for
the same animal. What would you picture in
your mind if someone said he saw a panther on
the way to school? Would you picture a smallish
brown wildcat, or a large black one? Scientists
need to know precisely which animal is being
discussed.
Previewing Activity
• Each choice should lead either to the name of
one item or another choice.
• Each choice must be “positive”—tells what
something “is,” not what it “isn’t.”
• Each choice should describe something easily
seen on the object.
• The choices go on until the user has enough
information to name all five objects.
Students should either bring the five objects in
during the next class period or draw pictures of
the objects on the homework paper.
Procedure—Day 2
Reflection
Have students trade homework (both the key
and the five objects or pictures) and work
4
The naming system most scientists use today
was created by Swedish botanist Carolus
Linnaeus [cur-OH-lus luh-NAY-us] in 1757. This
system is what we refer to as taxonomy.
Scientists who specialize in classification systems for organisms are called taxonomists. All
living organisms are classified into taxonomic
groups. The taxonomic system created by
Linnaeus is based on a series of categories,
called a taxonomic hierarchy, that get more and
more specific. The taxonomic hierarchy of animals consists of these categories (list them in a
vertical column on the board): Kingdom,
Phylum, class, order, family, genus, and species.
Underline the first letter of each of the seven categories, and then project or otherwise share the
drawing provided here as a visual aid. Ask someone to describe the picture, and then explain
that this picture is useful to help students
remember the taxonomic hierarchy. Pictures or
rhymes that are used to help remember some-
Agency for Instructional Technology • www.ait.net
Lessons ALIVE: Engaging Learners with Video
Repeat the mnemonic, asking students to recite
it with you: Kings Play Chess On Fine-Grained
Sand. If you created a poster from the PDF, leave
it up during the next part of the lesson and occasionally ask a student to repeat the mnemonic.
Video
thing like a list are called mnemonic devices.
Take students through the mnemonic step by
step to help them use visualization to remember
the categories:
• Point to the kings in the picture, and say: The
kings help you remember the “Kingdom” category. (Write “kings” next to “Kingdom.”)
There are only five Kingdoms, or main categories, of all living things on Earth. All animals
are found in the Animalia, or Animal
Kingdom.
• Point to the chessboard and say: “Kings play
chess” helps you remember “Kingdom,
Phylum,” and “class.” (Write “play” and
“chess” next to their matching categories.)
Each Kingdom is divided into smaller groups
called “Phyla.” Who can guess how we get
“classes”?
• Point to the sandy beach and explain that this
is very “fine-grained” sand they’re sitting on.
Write “on,” “fine,” “grained,” and “sand” next
to the last four categories.
Prepare students to view the video by pointing to
the word “Phylum” on the board and asking students what Phylum the bugs they sorted in the
first activity belonged to (arthropods). Explain
that the next video they will see describes some
of the “classes” that the Phylum Arthropoda is
divided into. CUE program 3 from the series Life
on Our Planet, “Insects, Insects, Insects” to
approximate time code 1:13 (where the narrator
begins, “We could say that the Earth is largely
inhabited by insects . . .”). Continue to approximate time code 2:38 (after the narrator says,
“. . . protecting their internal organs from many
external forces.”)
Create a simple graph on the board as you discuss in very simplified terms the body plan
details of the four classes of the Phylum
Arthropoda discussed in the video.
Group Work
Divide the class into groups of four or five and
explain that they’re now going to get the chance
to create a brand new species of arthropod. First
they will choose an arthropod class (myriapod,
arachnid, insect, or crustacean), and then they
will work together to build a new species using
Arthropod Body Plan Details
Body Sections*
Legs
Antennae
Wings
Phylum
Myriapods
2
Many pairs
1 Pair
Never
Arthropoda
Arachnids
2
4 pairs
Never
Never
Insects
3
3 pairs
1 Pair
Sometimes
Crustaceans
2
5+ pairs
2 Pairs
Never
*Myriapods’ bodies consist of a well-defined head and body. Insects have a head, thorax, and
body. The other two classes have a combined head/chest area and a second body section.
Agency for Instructional Technology • www.ait.net
5
Lessons ALIVE: Engaging Learners with Video
the craft materials and found objects that the
class has been gathering.
As your group creates a new arthropod, you
must come to an agreement on the following
choices, based on the information about the differences in the four classes’ body plans.
• Will your new arthropod have a body divided
into two or three parts (covered by an
exoskeleton)?
• How many appendages, and how are they
modified?
✓ Pairs of jointed legs in sets of three, four,
five, or many?
Procedure—Day 3
Group Work, continued
Allow groups more time to complete their
arthropod models, and then display them somewhere in the classroom before moving into the
next topic. They will be returning to their models
again during the future activity.
Introduce New Topic: Greek and Latin
Naming Conventions
Ask students to explain some of the most important reasons that scientists need to classify and
identify organisms. (Answers: make connections
among groups of organisms, communicate with
other scientists more easily, and understand
about the history of life on Earth.)
✓ Antennae—none, one pair, or two pairs?
✓ Wings—present or absent? (NOTE:
Remember—only a few species of insects
have wings.)
Create your arthropod’s body from boxes or cans
(be sure to leave it flexible between body parts),
and then add appendages, antennae, or wings,
according to the class of arthropod selected, and
decorate the creature using any other materials
from the collection. Try to make your arthropod
look different from any known creature.
“Look deep into nature,
and then you will understand everything better.”
Explain that, in order to communicate effectively
with each other, it’s important to scientists that
they give animals unique names. As they saw
with the mountain lion example, if every scientist created a different name for each of the animals they studied, it would be very confusing.
For another example, how many students have
heard of a creature called a “roly-poly bug”? How
many have heard of “pill bugs” or “sow bugs”?
How many knew that all those names are the
same creature?
Scientists like things to be organized and tidy.
They wanted one name for every creature so that
when they talked to each other, everyone would
know what they were talking about. They also
needed a naming system that crossed language
barriers—no matter what country they live in, or
what language they speak, all scientists would
recognize these names for organisms. Once
again, the Swedish biologist Carolus Linnaeus
came up with the answer. He decided the names
should be in the Greek or Latin languages. Why
do you think he selected these two languages?
Some of the names you’ve already learned came
from these two languages. For example, arthron
—Albert Einstein
6
Agency for Instructional Technology • www.ait.net
Lessons ALIVE: Engaging Learners with Video
is a Greek word meaning “jointed”, and the
Greek podos means “foot”. So what does the term
“arthropod” mean? Arthropods are animals with
jointed legs (such as spiders, crabs, lobsters, and
beetles).
You’ve learned the classification system for animals—what is the mnemonic device that helps
you remember it? (“Kings play chess on finegrained sand.”) Linnaeus thought that hierarchy
was too long for easy communication, so he
came up with something called the “binomial”
naming system. Binomial means “two names.”
In a binomial naming system, only the last two
parts of the hierarchy, the genus and species are
used.
The following basic rules apply when creating a
binomial name for a new species:
• No two different species can have the same
combination of genus and species.
• No species is given more than one combination.
• The genus name is always capitalized and
italicized (or underlined when handwritten).
• The species is not capitalized but is always
italicized or underlined.
For example, the binomial name for a tiger is
Panthera tigris. It’s part of the genus Panthera
(large cats that can roar). There are only four
species of large cats that can roar. This one is the
species known as tigris. Binomials can be abbreviated by using the capital letter of the genus
and a period—P. tigris.
How does this naming system help scientists?
Using this system, we find that the correct scientific name for one species of the roly-poly bug is
Armadillium vulgare (pronounced arm-uhDILL-ee-um vull-GAIR). It’s actually not a bug at
all—it’s part of the crustacean class of arthro-
pods, so it’s more closely related to a shrimp or
crab. Out of the 1.25 million animals given binomial names, only one is called Armadillium vulgare. Now, when scientists talk about A. vulgare,
they all know exactly what creature they’re talking about.
Video
Prepare students for watching the AIT video
from Shape of Life, “Cnidarians: Behavior on the
Move” by explaining that this video isn’t about
the arthropod Phylum, but instead discusses the
Phylum that includes jellyfish—the Phylum
Cnidaria (pronounced Nye-DARE-ee-uh). Ask
students to share what they know about jellyfish
with the class before beginning the video, and
explain that they’re about to see that there are
hundreds and hundreds of different species in
the jellyfish class of cnidarians.
CUE the video to approximate time code 18:12,
in the black screen that follows the question,
“How do nerves control muscles to produce different behavior?” During viewing, ask them to
notice all the different species of jellyfish, and to
watch for a new species that these scientists discovered for the first time. PAUSE the video occasionally to allow students time to examine the
variations in the body plans of jellyfish. PLAY
through time code 28:06, after the narrator’s line,
“. . . a myriad of cnidarians living below 3,000
feet.”
Briefly review the video segment and discuss the
excitement and fun of identifying and naming
new species. Ask students to reflect on the features of the new species’ body plan that are similar to all jellyfish and those that are different
from any other jellyfish. Ask them to speculate
on a name that might best fit this newly discovered jellyfish. Explain that it is usually a scientist
connected with the expedition that first identifies the new species who gets to name it. Since
all students have been part of a group that “discovered” a new species of arthropod, they will
get the chance to give their creation a name.
Agency for Instructional Technology • www.ait.net
7
Lessons ALIVE: Engaging Learners with Video
Group Work, continued
Groups are now ready to create the taxonomic
hierarchy of their new species of arthropods.
Give them access to Internet-ready computers
and direct them to the U.S. Government’s Web
site for Integrated Taxonomic Information
System, found at www.itis.usda.gov. Have students first fill in categories 1–3, then search the
database for their chosen class of arthropods,
and work together to fill in the Greek or Latin
names for the three categories in No. 4 before
coming to an agreement on the brand-new
species name for their new creature.
1. Kingdom (Animalia)
2. Phylum (Arthropoda)
3. Class (choose from Myriapoda, Arachnida,
Insecta, or Crustacea)
To check for understanding, discuss with the
class why all jellyfish have the same designation
for the first three categories. Then explain that,
after the class Scyphozoa, jellyfish are further
divided according to other body plan details,
including their tentacle number and size, and so
on. Write in the order and family designation for
this new jellyfish.
Order: Semaestomae
Family: Ulmaridae
Once the scientists identified the family, they
were stuck. Not only was this new find a different species, but it also was a bit different from
other jellies in the Ulmaridae family. They had to
come up with a name for a new subfamily,
genus, and species. Here are the names they
used:
4. Choose an order, family, and genus.
Subfamily: Tiburoniiae (Ty-burr-OH-nee-ay)
5. Agree on a brand-new species name.
Genus: Tiburonia (Ty-burr-OH-nee-uh)
6. Finally, list the binomial name for the new
arthropod.
Species: granrojo (gran-ROH-hoh)
Have one member of the group neatly fill out a
label, indicating both the taxonomic hierarchy
and the binomial name for the new species.
Reflection
Ask students once again to predict what name
the new jellyfish they saw in the video may have
been given. Guide them through the first three
categories of the taxonomic hierarchy of jellyfish:
Kingdom: Animalia
Phylum: Cnidaria
Class: Scyphozoa
8
The subfamily and the genus are named after
the R-O-V, and the species name means “big red”
in Spanish, because the jellyfish is blood red and
from two to three feet in diameter. What would
be the binomial name for this jellyfish?
(Tiburonia granrojo or T. granrojo)
Assessment
Group Assessment
Evaluate each group’s work in creating a new
arthropod, designating its hierarchy, and naming
the new species. Their assessment should reflect
evidence of effective participation, collaboration,
and consensus, as well as an understanding of
the taxonomic system of classifying organisms.
Agency for Instructional Technology • www.ait.net
Lessons ALIVE: Engaging Learners with Video
As a further check on understanding, have the
group members work together to create a
dichotomous key. They should select the created
arthropods of four other groups and write a key
that uses similarities and differences of the
group to narrow down and identify each species.
Individual Assessment
Check for deep understanding of the concepts
behind taxonomic hierarchies by assigning students to write an essay on the following topic.
Mountain lions, pumas, cougars, panthers,
catamounts—these are all names for the same
animal: the largest of the small cat species,
binomial name Felis concolor. Using this
species as an example, list and explain three
reasons why scientists need to classify living
things.
ANSWER RUBRIC (Students who understand the
concepts taught in this lesson should write
essays that reflect the following facts): The first
reason is our natural inclination to group
organisms. We classify as a means of making
connections. Similar organisms may have similar
benefits or dangers. Grouping unfamiliar organisms with familiar ones gives us a foothold in the
unknown. The second reason has to do with
communication. Over a million different kinds
of organisms have been identified. In order for
scientists to study them, talk to each other about
them, and report their findings to the world, it is
necessary that each kind of organism have a
unique name. If every scientist created a different set of names, considerable confusion would
arise. For example, think about the confusion
that arises when people talk about mountain
lions, pumas, cougars, and panthers. Inconsistencies like this led scientists to create a universally accepted binomial naming system. The
third reason has to do with scientific understanding. We classify in order to understand the
relationships among organisms and their
ancestry.
“In the world of nature
things have a natural
tendency to be ordered in
the best possible way.”
—Aristotle
Extension Discussion:
What Is a Species?
Ligers and Tigons and Mules, Oh My!
The definition of “species” is based on whether
or not organisms can successfully reproduce
among themselves. Ask students what happens
when a female horse and a male donkey mate.
Explain that the resulting offspring, known as a
mule, has characteristics of both parents—it’s
part donkey and part horse. Does that mean that
a horse and a donkey are part of the same
species? No, because a mule is born sterile—it
cannot reproduce itself. The only way to make
more mules is to breed donkeys and horses.
Scientists say that, since the horse and donkey
cannot reproduce successfully (they can’t make
an offspring that is able to reproduce), they are
not of the same species. The binomial names
show that the two animals are part of the same
genus, but not the same species:
Horse: Equus caballus
Donkey: Equus asinus
First ask students if they think lions and tigers
are part of the same species. They may remember from the discussion of binomial names that
Agency for Instructional Technology • www.ait.net
9
Lessons ALIVE: Engaging Learners with Video
the tiger (and the lion as well) is part of the
genus Panthera, a group of four species of large
cats that are able to roar. Use a computer with a
projection device or take students to an
Internet-ready computer lab, and go to PBS’s
Evolution Library Web site, found at
www.pbs.org/wgbh/evolution/library/05/2/
l_052_02.html, to learn about lions, tigers, and
creatures known as tigons and ligers. Click on the
image and enlarge the pop-up window so that
all four animals are visible to all students. Tigons
and ligers, like mules, are the results of lions and
tigers mating and reproducing. They are born
sterile. Are they the same species? Once again,
the binomials show the difference:
Tiger: Panthera tigris
Lion: Panthera leo
through an easily accessible database. Teachers
or students may use this site as a reference for
reliable information on species names and their
hierarchical classification.
http://news.nationalgeographic.com/news/
2003/05/0505_030505_tvnewjellyfish.html
Read the May 5, 2003 article from National
Geographic Today about the Western Flyer’s discovery of the new jellyfish species, T. granrojo.
www.troy.k12.ny.us/thsbiology/taxowhales.html
You might want to play a taxonomy name game
with your class, like this one offered by the
Enlarged City School District of Troy, New York.
Troy High School’s Web site provides instruction
for a Whale Naming Game that will give your
students more exposure to Greek- and Latinbased binomial names.
You might wish to assign additional research on
ligers and tigons, asking students to discover the
difference between these two animals.
References
www.itis.usda.gov
This site, hosted and funded by the U.S.
Government, provides authoritative taxonomic
information on plants, animals, fungi, and
microbes of North America and the world
10
Agency for Instructional Technology • www.ait.net
Lessons ALIVE: Engaging Learners with Video
Dichotomous Keys: Identify the Aliens!
Name_____________________________________
Instructions: Select one alien from the group below. Follow the dichotomous key branches to
identify it, and write its name on the line. Repeat the steps for all five aliens.
________________
________________
________________
________________
________________
1a. The alien has no arms
>>>>
Go to Number 2
1b. The alien has arms
>>>>
Fleebits
2a. The alien has a two-colored head
>>>>
Morphiap
2b. The alien has a single-colored head
>>>>
Go to Number 3
3a. The alien has a straight neck
>>>>
Chizzle
3b. The alien has a curved neck
>>>>
Go to Number 4
4a. The alien has a neck ring
>>>>
Pooly
4b. The alien has no neck ring
>>>>
Lo Mo
Agency for Instructional Technology • www.ait.net
11
Lessons ALIVE: Engaging Learners with Video
12
Agency for Instructional Technology • www.ait.net