What are fossils?
The first thing that comes to mind when we hear fossils is dinosaur bones! But, fossils can teach us about any living thing – or organism from the past. In fact, a fossil basically freezes the living thing, or its trace, and allows us to view its bones, imprints, or even hair, millions of years later!
There are two types of fossils, body fossils and trace fossils. Body fossils can include the entire body of the organism, or just body parts. If you’ve ever been to a museum with dinosaur bones, these are what we are talking about! On the other hand, trace fossils show us the activities of past living organisms. This can include footprints and poop!
Body fossil of a Pterodactyl (the P is silent!). This fossil was found in Germany! (Photo credit: Jonathan Blair, https://education.nationalgeographic.org/resource/fossil/)
Trace fossils of human footprints. These are from 23,000 years ago, and found in New Mexico! (Photo credit: Dan Odess, https://www.nationalgeographic.com/history/article/fossil-footprints-challenge-theory-when-people-first-arrived-americas)
How are they made?
In addition to the two types of fossils, the way the fossils are made can be different! There are five different ways of fossil formation. These include: preservation of the original remains, permineralization, molds and casts, replacement, and compression.
Permineralization is the most common way fossils form. When a bone is buried, it will be exposed to mineral-rich water moving through the ground. The moving water places the minerals into empty spaces of the fossil. This hardens the bones and turns them into stone! Which allows us to dig up the bone many years later!
This is an example of permineralized wood! This particular fossil comes from the Blue Forest in Wyoming. This tree is about 34 million years old, meaning it is from the Eocene era! (2008, http://petrifiedwoodmuseum.org/permineralization.htm)
Amber fossils are an example of preservation of the original remains. The amber comes from trees, which can cover up organisms, such as insects. After the amber covers an organism, it will harden and protect it, allowing for scientists to look at the organism millions of years later!
This is a stingless bee preserved in amber! The bee is 16 million years old! This type of bee is closely related to honey bees and bumblebees. (David Green, 2010, https://naturemanchester.wordpress.com/2010/02/16/bees/)
Carbonization is another form of fossil formation. This happens when all of the elements of the organism are dissolved, except for carbon. This process leaves a residue, which shows us the outline of the organism.
This is a carbonized moth found in Colorado.This carbonization fossil was formed during the Eocene era (about 34 million years ago). (Photo credit: National Park Service, 2017, http://www.extinctblog.org/extinct/2017/7/9/the-transformative-value-of-fossils).
Why are fossils important?
Most fossils take at least ten thousand years to form. But, the information we can get from the fossils provides us with a picture of the past. Fossils also tell us about how we have evolved bacteria to humans! Fossils also teach us about animals that used to exist, and how they may have behaved, like knowing that a T-Rex can eat 500 lbs of meat in one bite! That is the size of an adult male lion!
Fossils in the biosphere?
Most of the fossils found in the Biosphere between 460 and 450 million years old! This means that these fossils are from the Ordovician period, which is the second period of the Paleozoic Era. A fun fact about the Ordovician period, Starfish existed during this time period as well!
This is a starfish fossil from the Ordovician period! This fossil was formed about 450 million years ago! (Photo credit: Natural History Museum, London, https://www.sciencephoto.com/media/436776/view/starfish-fossil)
Making your own fossil at home!
Another way fossil preservation can occur is through permafrost ice! (Permafrost ice is ice that has been frozen for at least two years!) Permafrost ice perfectly preserves the remains of organisms, allowing scientists to study them millions of years later!
You can make your own ice fossils easily at home, in 5 steps!
- Pick out your favorite insect or dinosaur toy you have! (CAUTION: this toy will get wet and cold!)
- Locate a plastic container that can fit your insect or dinosaur.
- Fill the container with water, and place your insect or dinosaur into the water.
- BONUS: add extra elements to your fossil such as food coloring!
- Place the container in the freezer for about 24 hours.
- The next day, remove your ice fossil from the container and take a look!
You can extract your dinosaur or insect using hot water or a small hammer, but be sure to ask an adult for help!