Learning from the Fossil Record
Grade 8 Science
Name:
Date:
Part1 of Performance Assessment Task
In analyzing other features around the fossils in each layer, the scientists were able to identify
some key features that struck them as interesting. They have sent you a description of the
environment that existed at each level, based on the features they found in each layer.
Deepest fossil layer: all
short skull and jaw
Long, skinny tail
Long front legs
Long back legs
No flukes on the tail
Next fossil layer:
some
short skull and jaw
Long, skinny tail
Long front legs
Long back legs
No flukes on the tail
Next fossil layer:
all
Long skull and jaw
Short, fat tail
Front flippers
Short back legs
Flukes on the tail
Next fossil layer:
all
Long skull and jaw
Short, fat tail
Front flippers
No back legs
Flukes on tail
Environmental Evidence:
mostly medium trees
some smaller shrubs
many small creeks
some
Environmental Evidence:
long skull and jaw
taller grasses
short, fat tail
small shrubs
short front legs
swampy
long back legs
no flukes on the tail
Environmental Evidence:
taller grasses
shallow ponds
swampy
Environmental Evidence:
larger, deep lakes
many aquatic plants
By studying present day animals with similar traits, they have inferred that:
1. Long skull and jaw are dominant over short skull and jaw
2. Short thick tail are dominant over long skinny tail
3. Long front legs is dominant over short front legs
4. Long back legs is dominant over short back legs
5. No flukes on tail is dominant over flukes on tail
They do know all of these fossils are related as the area was isolated and no other animals
could come in or go out of the area.
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Learning from the Fossil Record
Grade 8 Science
Name:
Date:
They ask that you add notes to your original report of your findings on the possible genetics and
inheritance of these traits.
Please include, in a new color, the following in your report.
1. Explanations for why the organisms’ features changed from one layer to the next.
Include specifics for each trait that changed.
2. More detailed explanations for those changes that occurred for reasons other than
inheritance.
Each answer will be scored on the following aspects:
a. Does the reasoning behind the answer make sense and is it possible? 0 1 2 3
b. Is the report organized in a logical manner so the reader can understand the explanations
provided? 0 1 2 3
The organisms feature, long skinny tails, changed from one layer to the next. This
organism changed, by instead of long skinny tails that all of them had in the beginning,
some were short fat tails in the next layer and some were the same as long skinny tails.
The long skinny tail is recessive ss. But it was still the more popular one over the dominant
short fat tailed genes. This makes the next layer make sense. Because in the next fssil
layer, short fat tails became equally popular with long skinny tails. The environment was
mostly medium sized trees, some small shrubs, and many small creeks. The organism
must have had a mutation. I have a feeling that the mutation was caused by excessive
sunlight or chemicals in the creeks. I believe that this is because that the chemicals in
the creek must have either killed or mutated the animal. And somehow recreated or
made the short tail dominant gene reappear. This mutation must have spread to
offspring over a few generations until it was equally popular to the long skinny tail gene.
The next layer had an environment that had taller grasses, small shrubs, and swampy.
This allowed other organisms to hide in the tall grass, and the swampy environment
would be good for being safe from predators. For the next layer they all had short fat
tails. Which to me seems like all of the other organisms with long skinny tails died. The
mutation was obviously an advantage because maybe the long tails would get stuck in
the swampy ground. While the short tails wouldn’t, or the dominant short tail trait spread
so is was just the completely dominant gene. So they ended up going extinct. The next
layer had taller grasses small ponds and was swampy. Where all of the organism
species had short fat tails. And nothing had really changed. And finally in the last layer
there were large lakes and many aquatic plants. And the species remained the same
with the short fat tail being the only existing trait for the species…at least for now.
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