First Fauna Fossils
By Patti Hutchison
Fauna is a term for animal life. In 1947, fossils of the
first fauna were found in Australia. They were casts of softbodied organisms made of many cells.
1
Scientists believe these animals existed during the late
Proterozoic Eon. The fossil record shows that many of
these organisms lived between 670 and 570 million years
ago. For millions of years before that, life was mostly
single-celled.
2
There were many kinds of organisms in this group.
Some floated about in the ocean. Others were attached to
the ocean floor. They simply absorbed nutrients from the seawater in order to survive. There was
no other animal life around to eat them, so they were safe floating or sitting in the ocean.
3
There is little evidence that these organisms moved on their own. Many ancient animals that
moved left trace fossils in the rock record. These fossils were tracks and trails formed in the rocks.
Scientists have found no trace fossils of the first fauna.
4
Scientists disagree whether these animals were ancestors to present-day organisms. Some
believe that they were. They looked much like some animals that live today. They had body
shapes similar to jellyfish and worms. Some looked like echinoderms. These are sea animals like
starfish and sand dollars. Others looked like arthropods or insects.
5
Some scientists believe that they were not related to any animals alive today. The ancient
fossils show no evidence that the organisms were able to store and digest food. These scientists
believe that it is just chance that these life forms were similar to animals that are alive today. In
fact, they are not sure whether they are plants, animals, or fungi.
6
Scientists have recently found these fossils in all parts of the world. This shows that these
organisms lived throughout the shallow oceans during the Proterozoic Eon. Then, suddenly they
disappeared from the rock record. Apparently, there was a mass extinction. This is another reason
why scientists disagree about whether or not they were related to modern-day life.
7
Name___________________________________
Mr. Hobbs
Date____________________
“First Fauna Fossils” HW
1. The word fauna means:
a. Fossils
b. Animal life
c. Extinction
d. Proterozoic
2. The first fauna fossils were:
a. Insects
b. Jellyfish
c. Soft bodied organisms with many cells
d. Mammals
3. How did organisms that were stuck to the
floor survive?
4. Animals like starfish and sand dollars are
called:
a. Echinoderms
b. Insects
c. Arthropods
d. Reptiles
5. When did the first fauna live?
6. Scientists are sure these organisms were
related to organisms alive today.
True
False
7. According to paragraphs 5 – 7, what are TWO (2) reasons that scientists disagree about the
fossils of animals that have ever been found? Support each of your reasons with specific evidence
from the article.
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First Fauna Fossils - Answer Key
1 Animal life
2
Soft bodied organisms with many cells
3 They absorbed nutrients from the seawater.
4
Echinoderms
5 during the late Proterozoic Eon; 670 to 570 million years ago
6
False