Dinosaurs - Lesson 2: Extinction
On this page
- Encountering the Idea
- Exploring the Idea
- Getting the Idea
- Organizing the Idea
- Closure and Assessment
BIG IDEAS:Life can cease to exist because the conditions on
earth that support it change and no longer meet a life form's needs.
Dinosaurs' needs were very great.
Whole Group Activities
- Book: What Ever Happened to the Dinosaurs? by B. Most
- Measuring tape to measure at least 50 feet or a 50-foot paper chain
- Paint brushes, a jar with water, lap chalkboard or similar writing surface
- Sorting trays with numerals zero to five written on the appropriate
- Appendix A - Dinosaur
- Word tags: extinction; disappear; evidence; diplodocus; theory
Have you seen a real dinosaur? Do you know how many dinosaurs exist today? Yes,
zero is the number that tells us how many dinosaurs are alive today. We will be
working with the number zero in the Mathematics and Science Centers
Read the story, What Ever Happened to the Dinosaurs? After reading, ask
the students if they think some of the author's ideas about dinosaurs could be
true. Tell students that they will be writing their stories about extinction at
the Writing Center.
In our first activity we will discover more about dinosaurs. Students complete
Activity - Measure a Dinosaur! as shown below.
50 feet of string; scratch paper, cut and strung into a chain at least 50
Paper chains of various lengths (heights of several of the students) to compare
to the dinosaur chain
Children go outdoors, if weather permits, otherwise use a hallway.
- Children hypothesize as to the size of dinosaurs.
- They measure 50 feet on a sidewalk or a hallway with the string; make a 50-foot
paper chain to represent the length of a dinosaur.
- Students compare the chain to their own heights.
- They estimate how much food a dinosaur like the one they measured would
need to eat every day. If they compare their height to the height of the dinosaur, can
they get a better estimate?
When you measured the dinosaur's size and then your own, who was bigger?
Who was smaller? If you put some of your chains together, were they all
together longer or shorter than the dinosaur? How do you know? Yes, you put
them side by side to compare.
At the Mathematics Center, the students, working in small groups or in
- classify the dinosaur models by color, size, and shape, after describing
them to their partners
- count a given number of dinosaurs to place under the correct numeral
written on the sorting trays
- say how many dinosaurs are alive now and point to the numeral that tells
that number, and continue sequencing the dinosaur shapes.
At the Library Center, the children continue to read and look at the new
book that was read for this lesson. Tapes of the book are available for the
children to listen to, as they "read" the new book.
None of us has seen a dinosaur. If that is true, how do we know that they even
existed? (Pause for student responses.) Yes, we may have never seen a dinosaur,
but we have seen parts of dinosaurs that have survived over millions of years.
These parts, which are mostly bones, that have survived suggest to us that such
things as dinosaurs existed.
We know that many of the animals such as the dinosaurs living on earth at the
time were very large. That means that they needed a lot of food, whether it was
plant or animal food. How much food did you estimate that dinosaurs the size of
the one we measured would eat every day? Yes, if we compare our size to theirs
and then estimate how much food we eat every day, we can get an idea of how much
more food they would need.
What would happen if the dinosaurs could not get enough food? Yes, they would
die. What else did they need? Air and water. If any of these needs were not met,
what would happen to the dinosaurs? Yes, they would die. What would happen if
they had many natural enemies and could not protect themselves? Yes, their
enemies would kill them.
Introduce the word "evidence"; show it on a word card. Tell the children
that there is "evidence", such as that found in fossils, that makes us believe
that dinosaurs existed many years ago even though we have never seen one alive.
We know how big or how small they were because we have measured their fossils.
Tell the students that there are several theories about what happened to the
dinosaurs. A theory is like a guess, but it is a guess based on information or on
the evidence that is available. In our lesson we will study some of these
Theories about the extinction of the dinosaurs suggest that:
All of these suggestions are possible. Scientists, however, still do not know for
certain why the dinosaurs ceased to exist. What do you think? What is your
- maybe their eggs were eaten by the dinosaurs' natural enemies, or by other
- maybe the land moved and caused the weather to change; when the weather
changed the plants living at that time were not able to thrive and produce the amount of
food needed to feed the dinosaurs, and the dinosaurs could not continue;
- maybe a large star caused an explosion of cosmic rays that killed them all;
- maybe a storm of meteors caused clouds to block the sun, which again
affected the plants because they could not produce the amounts of food the dinosaurs
1. Students illustrate and write about the size of the dinosaur they measured, and
how it compares to their own height.
2. At the Writing Center, students dictate reasons (which the teacher
writes on a chart) for why dinosaurs disappeared. Then the students write and
illustrate their reasons for why the dinosaurs became extinct. They trace and
write the word "extinct."
3. Students complete Activity - If I Were A Diplodocus. Students discuss
what a diplodocus is and then write or tell about:
If I were as long as a diplodocus, I would live ________, sleep _______,
go out to eat _________, be careful of my _____ . (The students can add to these
Complete the lesson with the recitation:
One Friendly Dinosaur
One friendly dinosaur wanted to play peek-a-boo.
She found another, then there were two.
Two friendly dinosaurs looked behind a tree.
They found another, then there were three.
Three friendly dinosaurs went to find some more.
They found another, and then there were four.
Four friendly dinosaurs in the water did dive.
They found another, and then there were five.
Five friendly dinosaurs played in the sun.
They all ran to hide; now there are none.
- How many of you made the dinosaurs "disappear" at the Science Center? Let's count.
- What expression did you use that means the same as "disappear"? (Become extinct.)
- How many dinosaurs exist today?
- Teacher: I am going to hold up my hand and show zero, one, two, three, four, or
five fingers. As soon as I hold up my hand and you know how many fingers I have
up, raise your hand and tell me the number.
- How do we know that dinosaurs existed many years ago?
- What do you think happened to the dinosaurs?
Assess students' participation in the activities and the level of
completion of their individual work. For example, assess a student's own
explanation for the disappearance of the dinosaurs and work on Activity -
If I Were a Diplodocus.