Fossil Facts & Worksheets | Formation, Findings, Importance to Science (2024)

Did you know that fossils serve as the window to our past? These preserved remains or traces of activities of different organisms give us so much information on how ancient organisms lived, how organisms evolved, and even how our planet changed over time.

See the fact file below for more information on Fossils, or you can download our 27-page Fossil worksheet pack to utilize within the classroom or home environment.

Key Facts & Information

WHAT ARE FOSSILS?

• Fossils are remains of dead organisms buried in sediments, frozen in ice, or encased in amber. Evidence of an organism’s movement or behavior is also a fossil.
• Fossils are a window to our past, especially to the numerous organisms that once lived on Earth. It serves as a piece of evidence for evolution, showing us how species have changed over time.
• Fossils show us how organisms lived before, how they looked, and how they behaved. The types of food they ate, the tools they used, and so much more.

FOSSIL FORMATION

• Fossils are of different kinds, and they are formed in different ways.
• An organism’s hard parts, such as bones, shells, and teeth, are mostly preserved and become fossils. The soft parts, such as skin, muscles, and leaves, rarely become fossils. These are known as body fossils.
• Meanwhile, traces of how an organism lived, what it did, and how it behaved are known as trace fossils.
• Here are some of the ways fossils are formed.
• Petrification
  • Petrification came from the Latin word “petra”, which means rock or stone. This type of fossil formation replaces the organic material with mineral-rich fluids containing calcium carbonate or silica.
  • Once a shell, bone, or tooth has been buried under sediments such as mud or sand, minerals can replace the organic materials. Once the minerals have replaced the entirety of the tissue, it turns into a stone.
• Carbonization
  • Fossils formed through carbonization usually turn out to be black or dark brown.
  • Remains of dead organisms are compressed over time, and pressure drives off the organism’s liquid and gases.
• Molds and Casts
  • When an organism dies, its shell or bones may form an impression in sediment.
  • Meanwhile, a cast is formed when the space is filled in by sediments and hardens.
  • A single organism can form both a mold and a cast.
  • Molds and casts only show the external features of an organism.
• Preserved Remains
  • Since an organism’s soft tissues are broken down by bacteria, it is rare to have fossils that preserve the whole organism with its soft and hard tissues.
  • Preserved remains are the rarest type of fossils. Organisms that have been frozen or encased in amber preserve all of their body. Thus, its physical and genetic makeup are intact.

DETERMINING A FOSSIL’S AGE

• As mentioned, fossils serve as a window to our past. A fossil’s age may range from thousand years old to millions of years. But how do we determine a fossil’s age?

RELATIVE-AGE DATING

• Do you have siblings? Are you the eldest, middle child, or the youngest? Answering the second question is like finding out your relative age compared to your siblings.
• Geologists use the same concept to figure out the relative age of fossils.
• If you visit the Grand Canyon, you will see different types of rocks on top of one another. These layers of rocks are called strata.
• The lowermost rock layer or strata is the oldest while the topmost is the youngest rock layer. Thus, a fossil found below another fossil is older in age.
• Relative-age dating allows geologists to put the fossils they have discovered in chronological order. It allows them to determine the relative order by which species have appeared on Earth.
• This method is best used in sedimentary rocks or volcanic rocks.

ABSOLUTE-AGE DATING

• Based on the ages of your family members, who is the oldest and the youngest? Where are you in that order?
• If relative-age dating of fossils is based on their placement in strata, absolute-age dating is based on the numerical age of the fossils.
• To determine a rock’s age, geologists employ radiometric dating methods, which are based on the natural radioactive decay of elements like potassium and carbon.
• The radiometric dating method can provide a rock’s numerical age by measuring the presence of a short-life or a long-life radioactive element.
• Radioactive decay is a process by which the nucleus of a radioactive atom transforms into that of a more stable isotope.
• Radioactive decay is a random event; thus, we cannot say when one atom will undergo the process. But, in a group of atoms, one or more will surely undergo radioactive decay.
• The time it takes for half of the atoms to undergo radioactive decay is known as its half-life.
• Suppose you have twenty atoms, ten of them transformed into a more stable isotope after 10 seconds; what is its half-life? If your answer is ten, then you are correct.
• How long will it take for the remaining ten to transform? Again, if your answer is ten, you are correct.
• Half-lives are important in determining the age of a fossil as it gives us an accurate number of how many seconds, hours, or years have passed since the death of an organism.
• Say, for example, the radioactive C-14 is present in all living organisms, but upon death, the levels of this isotope decline.
• The rate of decline can give us the exact number of years that have passed since the death of the organism.

FINDING FOSSILS

• We won’t be able to look through Earth’s natural history if we, humans, are not able to find and excavate fossils.
• Finding fossils is not an easy task. The combination of hard work, knowledge, and chance can help one find a fossil.
• Knowing where to look will surely help us in finding fossils. But where do we start looking?
• Fossils are mostly found in sedimentary rocks. The best places to look at are cliffs, river valleys, hillsides, road cuttings, and quarries.
• Although scientists conduct research before visiting a location, some people discover fossils by chance. Construction workers, farmers, and miners often discover fossils accidentally.

IMPORTANCE OF FOSSILS

• The discovery of fossils allows us to learn a lot about our natural history and evolution. It can also serve as evidence of how a supercontinent used to exist.
• In terms of natural history, fossils give us information on what organisms existed way before us and how they lived and adapted to their environments. These can also inform us of the time these organisms appeared and went extinct.
• All fossils ever discovered on Earth make up the fossil record. This consists of millions of fossils from thousands of species, and most are already extinct. This record can help us update the tree of life and see how each organism is related.
• The information we can get from fossils and the fossil record supports the theory of evolution. It can teach us how specific organisms adapted to their environments and how these adaptations are passed on from one generation to another.
• Aside from evolution, fossils can also serve as evidence proving the presence of a supercontinent called Pangaea.
• Rhynchosaur fossils were found in the continents of South America and Africa, and India. This goes to show that these countries and continents were once connected before.
• Furthermore, fossils of an amphibian species were found in the continents of South America, Africa, Antarctica, and Australia. Looking at the globes and maps we have now, these continents are no longer connected.
• Fossils, and their study of them, can lead us to important discoveries about our past. More importantly, how the Earth is constantly changing, and even the organisms living on it.

FossilWorksheets

This fantastic bundle includes everything you need to know about Fossils across 27 in-depth pages. These ready-to-use worksheets are perfect for teaching kids about Fossils. Fossils preserved remains or traces of activities of different organisms give us so much information on how ancient organisms lived, how organisms evolved, and even how our planet changed over time.

Complete List of Included Worksheets

Below is a list of all the worksheets included in this document.

1. Fossils Fact File
2. Uncovering Words
3. Self-Check
4. Fact or Bluff
5. Absolute vs. Relative
6. Is It A Body or A Trace?
7. Fossil-Nificance
8. Time Traveler
9. DIY Fossil
10. A Window to the Past
11. An Imprint

Frequently Asked Questions

What is a fossil?

A fossil is the preserved remains or traces of a prehistoric organism. Fossils can be of various types such as bones, teeth, shells, imprints, and tracks.

How are fossils formed?

Fossils are formed when an organism dies and is buried under sediment. Over time, the sediment hardens into rock and the organic material of the organism is replaced with minerals. This process, called fossilization, preserves the organisms remains as a fossil.

What can fossils tell us?

Fossils provide important clues about the history of life on Earth. They can tell us about the appearance, behavior, and habitat of ancient organisms, as well as how they evolved over time. Fossils also provide evidence of past climate and environmental conditions.

Where are fossils found?

Fossils can be found in many places around the world, but they are most commonly found in sedimentary rocks. Fossil-bearing rocks are often exposed on the surface of the Earth in cliffs, canyons, and other geological formations. Fossils can also be found in quarries, mines, and other areas where rocks are exposed.

What is the age of the oldest known fossil?

The oldest known fossils are approximately 3.5 billion years old and are believed to be of simple, single-celled organisms such as bacteria and algae. These fossils were found in Western Australia and provide evidence of some of the earliest life on Earth.

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