Dinosaurs - Teacher Background Information
Dinosaurs existed millions of years ago. These giant animals
lived on earth 200 million years ago, and they became extinct about 64 million
years ago, according to fossil finds. Scientists can only guess what they looked
like, what they ate, where they lived and how they died. There are several
theories of how dinosaurs became extinct: egg-eating mammals ate all the
dinosaurs' eggs; a continental shift caused the weather to change, and shallow
areas where animals could graze and drink began to disappear; a large star close
to earth exploded, emitting deadly cosmic rays that destroyed the dinosaurs; or a
meteorite storm on earth caused huge clouds and steam to block the rays of the
sun, causing an ice age, during which the warm-blooded mammals that were prey for
the dinosaurs could not survive.
Initiate the unit by having students make a list on the bulletin-board-size
dinosaur poster of all the things they would like to know about dinosaurs. After
making the list, the students make guesses, or suggest hypotheses, about the
answers. During the implementation of the unit, whenever a student finds an
answer, she/he puts it on the board next to the corresponding question, after
it has been agreed to by the rest of the class. The student supports the
answer by telling where it is found in a book, why a calculation is made, or
where there is other evidence to support the claim.
The suggested teaching strategies are role playing and problem solving. As
the students pretend they are paleontologists, they travel in a time capsule to
the world of the dinosaurs where they can study them in their habitat and make
guesses about why they became extinct. The role playing suggests a prehistoric
time. The students begin working on a mural, coloring a large dinosaur cutout of
butcher paper, on which students will display their work, as they complete it.
As the students learn more about the dinosaurs and their time, the students add
these details to the mural.
The word "dinosaur" means terrible lizard. Dinosaurs lived in the Mesozoic Era,
before people populated earth. The earth was warm and covered with plants at the
time dinosaurs lived. All dinosaurs lived on land or were amphibious; none had
wings or paddles. Dinosaurs' eggs were not huge, but they were hard shelled, and
dinosaurs were meat eaters (carnivores) and/or plant eaters (herbivores).
All dinosaurs walked fully erect. Modern reptiles like lizards and crocodiles
walk with their legs sprawling out from their sides. Dinosaurs are the only
reptiles that walked like mammals, some walking on two legs, some on four. All
four-legged dinosaurs were herbivores. All carnivores were two-legged, although
some herbivores were two-legged as well. All dinosaurs had special skeletal
features: unique skull openings, hip arrangements that permitted them to walk
erect, and straight thigh bones.
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