Education is an important part of the Bruce Museum mission. We have hands-on programs in both science and art, and I recently had the pleasure of testing an upcoming activity with one of our museum educators. The activity is tied to our current science exhibit, Secrets of Fossil Lake.
Secrets of Fossil Lake tells the story of a lake from ancient Utah and Wyoming. 52 million years ago this lake was home to an abundance of fish, as well as varieties of early mammals and birds. Reptiles such as turtles, crocodilians, and lizards also made this area their home. We know this because of the fossils they left behind.
Sometimes plants and animals are fossilized individually while other times they are preserved with additional plants or animals alongside them. When we see multiple organisms fossilized together we know that they must have lived and died together as well. With this, we can start to put together a story.
In the case of the monitor lizard above, we can see that it was fossilized with several Knightia fish. Based on the proximity of both lizard and fish, we can guess that the monitor lizard may have been a habitual swimmer, or might even have fed on Knightia fish. Modern monitors swim and eat fish, so this wouldn't be far-fetched to suggest.
In our activity, we made "fossils" with stories to tell. First, we assembled an assortment of plastic aquatic plants and animals. Next, we rolled out clay to be our sediment. We pressed our chosen plants and animals into the clay, leaving behind impressions.
Fossilized impressions of life are called trace fossils. Trace fossils can take many shapes, including footprints, animal burrows, or impressions of the plant or animal themselves. The fossils of Fossil Lake include skeletal and plant material so cannot be considered trace fossils, but this is still a good way to approximate the diversity we see in Fossil Lake.
I added the impression of plants and a stingray near my crab. Stingrays eat crabs and crabs often hide themselves in aquatic plants. The story of my "fossil" grew more vivid with each new species I added.
Once I'd completed my composition, it was time to pour plaster over the clay. This is a good analog for the fossilization process. Fossilization occurs when layers of sediment cover a deceased organism or impression and harden over time. Fortunately, we didn't have to wait thousands of years for plaster to harden!
After the clay was removed, my creation was finally complete (Though it could use a trim to remove the excess plaster). Just like our fossils from Secrets of Fossil Lake, it shows a snapshot of a scene from the past. In my scene there is a preserved food chain, with a shark that could feed on the stingray and snails that feed on aquatic plants.
Until we invent time machines, fossils are the only way we have to see what life was like in the past. Interpreting those fossils can be difficult, but this exercise provides a glimpse into the thought process that goes into it.
All of our education programs include engaging, hands-on activities. School groups interested in scheduling a visit should contact Amanda Skehan, Interpretive Services and Audience Engagement Assistant, at email@example.com
-Kate Dzikiewicz, Paul Griswold Howes Fellow