This lesson helps students understand specialized structure and variation.
Background for Teachers
This lesson helps students understand specialized structure and
variation. These terms are very similar in that specialized structures
often vary across a species to accommodate different environments. This
can be confusing to students. Use this lesson to solidify these two terms
and their differences.
Discuss how specialized structures and variations help species survive
in their environments. Point out the obvious creatures such as lions,
cheetahs, giraffes, bears, and others that have obvious specialized
structures. Write the names of two similar species on the board and have
groups analyze them using Venn Diagrams for specialized structures.
Then analyze the specialized structures based on variations from
environment to environment.
To follow up, discuss humans and how we have many specialized
structures that aren’t so glamorous or exciting, but help us survive just
the same. Using cooperative learning groups, students investigate
specialized structures that humans have and tell how they help us survive
in our environment. Each group presents what they think is the most
important specialized structure on their list.
As a conclusion, discuss each of the specialized structures and decide
if they might have variations in different species of animals.
Intended Learning Outcomes
1. Use Science Process and Thinking Skills
3. Understand Science Concepts and Principles
Invitation to Learn
Ask for two volunteers to come up for an experiment. Wrap their
hands with a few rounds of masking tape so that their thumb is immobile.
Have them play a game of Tic-Tac-Toe on the board. The trick is to write
without the use of their hands. After expected laughter and giggles, calm
students down, take the tape off, and ask them to go ahead and play.
When they are finished, ask how it felt not have use of their thumb.
They probably didn’t realize how important their thumb really was until
then. Introduce the lesson with discussion about specialized structures.
You may also incorporate a survival item such as opening a peanut for
- Write the terms specialized structure and variations on the board
and have the students tell you what they mean. Instigate a
discussion about how specialized structures help species survive
in their environments. Point out the obvious creatures such as
lions, cheetahs, giraffes, bears, and others that have obvious
specialized structures. Talk about their specialized structures and
what they allow them to do.
Note: ADD POWERPOINT HERE IF POSSIBLE, or create
transparencies from pictures found on the PowerPoint
provided at the CORE Academy session.
- Now narrow it down to a few different species. Write five
different species pairs on the board such as Polar Bear/Grizzly
Bear, Zebra/Mustang, Snowshoe Hare/Jackrabbit,
Crocodile/Alligator, and Pelican/Woodpecker. Draw a Venn
Diagram underneath each pair. Divide the class into five groups
and assign each group one set of animals on the board. They
have two minutes to think of the specialized structures the pair
has in common. One representative from each group comes to the
front to complete the center of the Venn Diagram with common
specialized structures. While they are doing this, hang up a
poster-sized Venn Diagram comparing a Chihuahua and an
Alaskan Husky. Have five specialized structures written down the
middle as an example for them. When their two minutes are up,
have another representative present their findings to the class.
Once each group has presented the specialized structures, have
them move on to discussing variations.
- Show the class your example of Chihuahuas and Alaskan Huskies.
They have many specialized structures that are the same, but even more interesting are the variations in those structures that help
them survive in their environments. Talk about the different
environments these members of the dog family live in. Would
this affect their specialized structures? They both have fur, but
does a Chihuahua need as much as the Husky to survive in
Mexico? They both have claws, but an Alaskan Husky probably
needs longer, stronger ones to actually kill his food (which is
probably the size of the Chihuahua!). Complete each side of the
Venn Diagram addressing the variations in the specialized
structures; in the middle address what they have in common.
- Have students think of how their specialized structures might vary
for each animal. They may find that some of them don’t vary
much at all (zebra’s hooves and mustang’s hooves might not be
different enough for a fifth grader to point out). Have a
representative write their findings on either side of the Venn
Note: Either continue with the remainder of the lesson the next
day or shorten the first section to fit it into one day.
- It is good to have the students relate what they have learned back
to their own species. Discuss humans and how we have many
specialized structures that aren’t so glamorous or exciting, but
help us survive just the same. Put the students into different
cooperative groups and give them a Human Body Outline. Have them come up with at least five different
specialized structures that we have and tell how they help us
survive in our environment. Each group presents what they think
is the most important specialized structure on their list. Hang a
four-foot outline of a fifth grader on butcher paper on the board.
Each group sends a representative up to draw the specialized
structure with quick explanations on the body. Once all groups
are done, review and talk about each of the specialized structures
and decide if we even have variations. Propose the situation of
one student whose family has lived in the northwestern part of the
world for generations and generations—hundreds of years.
Compare to a student from Africa or Alaska whose family has
lived there for generations and generations. Would they have
- Go through each of the specialized structures listed on the class
body and discuss what variations might be there—skin color, skin
thickness, eye color, hair color, hair texture, facial shape, body
structure differences, feet, toes, body hair, etc.
Strategies for Diverse Learners
ESL and Special Needs Learners
- The PowerPoint presentation comes in handy for students with special needs and ELL learners. Visual images help them follow the presentation and be more involved in the comparing process. If a PowerPoint presentation is not available, having pictures of the animals you are comparing is crucial to helping the new ELL
student glean substance from the lesson. All learners are more stimulated with pictures of the animals to refer to.
- Group your low achieving and ELL students with others who will work with them and not do the brainstorming for them.
- In some cases it might help for you to have special needs students work with you on your dog Venn Diagram. If you do not have pictures for all the animals, try to have them for this pair.
Gifted and Talented
- Encourage students to do further research on their animal pairs. Pairs of students study one of the animal pairs and provide the class with a mini-report on their findings.
- If students have been trained in PowerPoint, they can create a presentation with additional pictures and photos from CD encyclopedias of their animal pairs.
- Provide modeling clay and embellishments for pairs of students to create pairs of animals in the same species. They must show five variations on five specialized structures.
- Students complete a creative writing assignment on two to three
specialized structures or variations they wish they had. You could
give them a story line with the main character, villain, and
problem, then let them come up with specialized structures and
variations that would help them solve the problem. Involved in
the plot could be a different environment that might spark their
imaginations as to what kind of specialized structures and
variations to give themselves!
- Create a worksheet that introduces students to a new type of
species with three very specific specialized structures. Introduce
three possible variations for each specialized structure. Have the
students calculate how many different combinations can be made
to see how many truly different subspecies there could be of this
- After completing the discussion on human specialized structures
and their variations, have students write a summary of what a
specialized structure is and why it is important to survival.
Include why specialized structures vary and give an example of a
- To turn this into a more in-depth expository or research writing
assignment, provide one to three paragraph summaries on
different animals for the students to use in their assignment.
(First or second-grade level animal books work great for this
because the information is simple and easy to read. The students
won’t get overwhelmed with the material they need to read and
- They can do a mini-research report on a particular animal
focusing on its specialized structures and its variations for its
particular subspecies. These reports act as an assessment tool
where students give examples of the specialized structures and
variations and explain how they are related to survival in the
Have students create and take home a matching game of two
similar species and the specialized structure that they share. It
could be played like Go Fish. Twenty sets of animals is
sufficient. Students tell the variation in the specialized structure
for each animal when they get a correct match in order to keep
Give the students paper with pictures of a pair of similar animals
in the same species. Have them construct a Venn Diagram
showing their specialized structures and fill in the variations that
go along with each. Give at least five answers in each part of the
Venn Diagram. On the bottom of the sheet, explain why there are
variations in specialized structures. They should be able to tell
you that it is due to the different environmental needs for survival.