Larva
Locomotion
How Are Larvae Adapted to Their Environment?
Before
You Watch |
It's
a good thing monarchs migrate by flying instead of walking! These
video clips show how monarch larvae walk, in normal speed and in
slow motion.
-
Describe in writing how you think a caterpillar walks, based on
your memory (or your imagination).
- Think
about how people walk and write a very careful, step-by-step description.
(Have a volunteer walk in slow motion so you can visualize all
the tiny changes in the muscles and joints. And/or, watch this
video clip of a person
walking in slow motion.)
- For
homework tonight, watch a dog walk. How does it keep track of
all four legs? Do its front legs jump ahead and the back legs
follow? Wouldn't it be confusing to walk with four legs? Get down
on all fours and try it yourself. How does your gait compare to
a dog's?
|
Another
Step: Insect Anatomy |
You'll
need some information and new vocabulary to describe what you're
about to see: All insects have six legs. That includes monarch butterflies,
even in the caterpillar stage. The pictures below show one side
of the caterpillar. If you count, you might think you're seeing
8 pairs of legs. But the leg-like structures you see in the rear
are not actually legs. They are called "prolegs." A proleg
is an appendage that looks like a leg, and acts like a leg, but
is not a true leg (embryologically speaking).
How
are the monarch's prolegs different from its true legs?
True
Legs
|
Prolegs
|
-
located
on the monarch's thorax
-
segmented,
with joints
-
present
in adult insect
|
-
located
on the abdomen
-
not
segmented, no joints, fleshy & shaped like a cylinder
-
disappear
in the adult butterfly
|
|
Watch
the Clips |
How
Do Larvae Walk?
Now that you've watched carefully, describe how a monarch caterpillar
walks:
-
Which of the monarch's legs or prolegs does it move first? Were
you surprised?
- How
are the legs and prolegs used differently? Write a step-by-step
description of larva locomotion.
- Describe
the challenge the monarch faces when walking on a leaf.
- How
is the caterpillar’s method of walking helpful for balance?
- How
does the caterpillar's body change as it walks?
- If
the prolegs could talk, what do you think they would say to each
other?
- Generate
research questions while you watch. (For example: What is on the
ends of the prolegs? Are they sticky? How can a caterpillar walk
upside down on the bottom of a leaf without falling?)
- Watch
these video clips of a pony,
a person
and a pigeon
walking. Compare and contrast larva locomotion to that of other
animals. (Does a caterpillar slither like a snake? Crawl like
a turtle? Hop like a bird?) Use similies to enhance your description.
- Did
You Know? After watching caterpillar locomotion engineers have
designed heavy construction equipment, needed for driving on difficult
terrain. Can you find other things that people have designed based
on examples in nature? (See PARC'S
Modular Robotics for some fun examples.)
|
Pulling
it Together: Adaptions to the Environment |
How
Are Larvae Adapted to their Environment?
- Where
do monarch larvae spend their time?
- What
special needs do they have?
- What
are the characteristics of a milkweed plant? Look closely. Use
a magnifying lens for an even closer inspection. What new things
do you see? Can you find ways that the monarch's feet are adapted
to those characteristics?
- Look
at the clip again. See if you find more ways that monarch larvae
are adapted to their environment.
|
National
Science Education Standards
Science
as Inquiry
Ask a question about objects, organisms, events. (K-4)
Identify
questions that can be answered through scientific investigations. (5-8)
Use data
to conduct a reasonable explanation. (K-4)
Life Science
Each plant or animal has different structures that serve different functions
in growth, survival, reproduction. (K-4)
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