1. Fossils
8.E.6A.4 Construct and analyze scientific arguments to support claims that different types of fossils provide evidence of (1) the diversity of life that has been present on Earth (2) relationships between past and existing life forms, and (3) environmental changes that have occurred during Earth’s history

2. Fossils
Fossils are mineral replacements, preserved remains or traces of organisms that lived in the past
Fossil Record
Collection of fossils and their placement in chronological order
Documents the existence diversity, extinction, and change of many life forms and environmental changes throughout history of life on Earth

3. Fossils and Their Environment
Thousands of layers of sedimentary rock not only provide evidence of the history of Earth but also the changes in organisms whose fossil remains have been found in those layers
Erosion and weathering of sedimentary rock layers can cause the destruction of fossils and result in gaps in the fossil record

4. Certain environmental conditions favor certain fossil formation
Type of fossils found in an area can explain the environmental changes that have occurred
Rapid burial of organisms (more likely marine environment), results in greater likelihood that the remains of marine organisms will be preserved.
Volcanic ash and Flash floods will help preserve land organisms
Certain fossilized organisms could only live in specific environments or under particular climate conditions
Extinction of life forms as well as how and when new life forms appear is part of the fossil record

6. Fossils and other organisms
Fossils can show structural similarities and differences in organisms over time revealing the vast diversity of life forms that have and continue to exist on Earth
Anatomical similarities and differences between various organisms living today and between them and organisms in the fossil record
enables the understanding of the diversity of life that has been present on Earth
Comparisons between living organisms and fossils also allow scientists to make inferences about the lines of descent

7. Types of Fossils
Mold- Sediment buries organism, organism decays, leaves a hollow mold in the shape of the organism
Cast- Mold filled with sand and mud to harden into the shape of the organism
Petrified (Permineralized)- Minerals soak into the remains, Replaces remains and turns into rock
Preserved- Remains stay intact and do not decay (preserved in rock, ice, tar, or amber)
Carbonized- Sand, mud, or rock squeezes organism’s decaying material out and leaves an imprint of the organism
Trace- mud or sand hardens turning the track, or trail of an organism into rock