Video Transcript
The picture shows a piece of
amber. What type of fossil has been
preserved in this amber? (A) Complete body fossil, (B) trace
fossil, (C) petrified fossil, (D) cast fossil, (E) mold fossil.
This question is asking us about
amber, which is a type of fossil. So, what is a fossil anyway? A fossil is the preserved remains,
such as bones or shell, impression, or trace of an organism that lived many years
ago. Since we’re looking at amber, let’s
discuss how this can form.
Millions of years ago, a tree
produced some sap. An unlucky mosquito happened to
land in the sap and got stuck. This tree sap was very sticky, but
over time it dried out and fell to the ground. In order for any fossil to form,
including this tree sap here, it needs to be buried under many layers of
material. This can be sand from when a giant
sand dune falls on top of the tree sap or volcanic ash when a nearby volcano
erupts. Or it can be mud that forms another
layer.
Remember, this is all happening
over millions of years, so many layers can form. And over all this time, these
layers pile on top of each other and get compacted because of all the weight of the
layers on top. Over time these layers become rock,
which we call sedimentary rock. Anything inside this rock is
preserved and fossilized, even our chunk of tree sap here. This fossilized tree sap is called
amber and contains the complete body of the mosquito preserved.
There are many different types of
fossils, and you can see some of them listed as answer choices. Mold, cast, and trace fossils are
fossils that are imprints of an organism or its behavior, such as a footprint. Petrified fossils can be the bones
of an organism itself that have turned to stone. A complete body fossil is what we
see here, where the entire remains of an organism are preserved, even the soft
tissue that would otherwise degrade over time.
Therefore, the type of fossil
contained in the amber is given by answer choice (A), complete body fossil.
