Animals are more
difficult to design
than seaweeds, but
they are more fun,
too. Be sure to
think carefully as you
work. Everything
has to come from
something already in
the ancestor, or be
something that could
logically
evolve. For
example, a fish will
never evolve into a
crab, and a crab will
never evolve into a
fish, because their
body plans are too
different and
evolution generally
goes forward, not
backward. Once
you have a basic body
plan, develop the
shapes and life styles
that could logically
come from
it.
It
helps to talk your
ideas over with your
partners and to make
some sketches before
you do the computer
work. Save time
and do the thinking
first.
Part
One: Design the Basic
Ancestral Animal
| Design
Step 1: Create
a Single Cell. |
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Begin with some primitive animal cells. Include the nucleus
and some organelles.
I have named this cell species The Blob. It will be the ancestor
of all my animals.
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| Design
Step 2: Sketch
a Clump of
Cells. |
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Cut, paste, reduce -- now you have a clump of cells!
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| Design
Step 3:
Play with the Idea of Shapes |
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Reduce the size of the cells and put more of them together.
Play with shapes a bit.
Could this somehow be the beginning of
an organized life form?
It
is still very
small.
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Design
Step 4: Make a Simple Animal
 Reduce the size of the cells further
and combine them to make a blobby little animal.
We have a tiny animal here. It is about a quarter of an inch
long, and semi-transparent. It has short, fine bristles. It also
has brown light sensitive spots running down its body. It crawls
and oozes along. This is a plant eater. Its mouth is on the end
at the right. This is the ancestral animal. I have named it the
Lumpy Crawler.
It lives among the rocks in a warm, shallow sea with not much
wave action.
Design Step 5: Start Thinking About the Environment
Where does this little animal live? It is probably crawling
around in the shallow water plants growing on the rocks. It eats
the plants (that I made last week.) It has short bristles for
protection. But does it have a future?
Design Step 6: What about Reproduction?
These little animals reproduce both sexually and asexually.
They have a pair of special organs that make eggs or sperm. Eggs
and sperm pass out of their bodies through pores in a fold on
the sides of their bodies.
Sexual Reproduction: If food is plentiful they make
eggs and sperm which they release into the water when they meet
another animal of the same kind. Each parent contributes half
of the chromosomes, so the new animals combine the characteristics
of their parents and differ from each other.
Asexual Reproduction: When food is scarce, these
little animals may not find others of their kind. They release
cells which have a full set of chromosomes identical with that
of the parents. All of the young who survive will be clones of
the parent and identical with each other.
Part Two : Diversify
into More Niches
Biome
One: The
Jumping Muncher lives in
Shallow Water
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Adaptation Step One: Begin with
Primitive Ancestral Animal.
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We start with the
Lumpy Crawler, the
small animal that
we have already developed.
It
is about to become
an ancestor!
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Adaptation
Step
2: Document Important Changes in
Body Form
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After
millions of years, the little animal has a brownish mottled skin,
making it hard to see. It has short spines for protection. It
is a herbivore, and still lives in the shallow water among the
rocks.
It has developed a stiff tab on each
side of the front of its body and another at the back end of
the animal. It uses the front tabs to drag itself along, and
pushes with the back tab. Mobility has improved.
It can tell light from darkness because
of eye spots on its sides.
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Adaptation Step Three: Show Improvement
in Fitness to Survive |
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Many
millions more years have gone by.
The tail of the jumping muncher
is now tucked under its body, and can be used to push the animal
forward quickly.
The little herbivore is now about two
inches long.
It can see movement in the environment, so it sees its predators.
Reproduction is now mostly sexual, as
the animals are successful enough to be able to find mates most
of the time.
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Niche Two: Tentacle
Mouth Eats Everything!
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Adaptation Step One: Begin with
the Primitive Ancestral Animal.
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This is the
Lumpy Crawler that evolved earlier.
It is a tiny plant eater that lives
in the rocks in shallow water.
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Adaptation
Step
2: Show Differences
in Structure
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The animal is developing short tentacles
for grasping food and pulling itself over the rocks. It is eating
plants and bits of debris.
It continues to live among the rocks
in shallow water but
has expanded its range
into the deeper off-shore
waters. Its color is
changing to help it to be
invisible among the brown
seaweeds.
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Adaptation Step Three: Show
Development of
Adaptive
Structures |
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Millions of years have gone by.
The tentacles are working -- they are
longer and stronger. The animal is bolder, sometimes catching
and eating smaller animals. It is growing plates of shell on
its back. It is still living among the
rocks and seaweeds
. The eye spots in
front of the body see movement.
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Adaptation Step Four: Note How
Evolution Continues |
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Millions of years have passed.
The animal is
well adapted to its home among the
rocks and seaweeds. It is protected by
a shell over its body, and has long, flexible tentacles to help
with locomotion and the capture of food. It eats plants and animals.
Reproduction is mixed, both asexual
and sexual. There are many of these animals around in the warm
shallow seas, but they move slowly, and so may
have difficulty
finding each other,
especially among the
taller seaweeds.
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Niche
Three: Razor-Strap:
a Carnivore
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Adaptation Step One: Begin with
the Primitive Ancestral Animal.
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Can
the Lumpy Crawler
evolve to change in
yet another way?
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Adaptation
Step
2: The Animal
is Getting Longer.
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Millions
of years have passed. The animal
is getting longer and thinner. It can move more rapidly through
the rocks. It is beginning to eat other animals.
It reproduces sexually so that its many
children differ from each other. The fastest and most ferocious
become the parents of the next generation.
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Adaptation Step Three : Adaptation
Continues |
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Over more millions of years the animal gets
longer, thinner, and faster. Its spines begin to support a band
of skin that helps stability when it swims. It is beginning to
be a predator, chasing down other small, moving life forms. It
can see its prey moving in the water. This is a new species of
strap swimmers.
It is venturing out
further from the shoreline
and exploring new
environments.
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Part Three:
Diagram Relationships
 This chart shows the family tree of these animals
and how they are related to each other.
They could continue to evolve and diversify
out into many different species of descendents.
They could change in order to adapt
to new environments.
Header by Viau from
tide pools,
Olympic National Park
©
1996,1997, 1998, 1999,
2000, 2002, 2003.
Elizabeth
Anne Viau.
All rights reserved.
This material may be
used by individuals
for instructional
purposes but not sold.
Please inform the
author if you use it
at
eviau@earthlink.net
.
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