We’ve had an abundance of babies over the past year. Check out the April
issue of ZOONOOZ to revisit the arrival of some of our youngsters and
see what they’re up to now. Download on iPad, Kindle Fire or desktop.
A fossil is the remains or traces of an organism preserved from the past and they can be exceptionally preserved, recording extremely fine detail or some remains of soft tissue. There are certain conditions that lend themselves to exceptional preservation, including rapid burial, low energy, lack of oxygen and acidity. If an organism is buried rapidly in a protective material such as a soft clay it will be protected from both weathering processes and scavengers. This is not enough to guarantee exceptional preservation, and so it may be combined with other factors; low energy environments for example are the best chance of fossilisation and both a lack of oxygen or high acidity reduce decay, among other factors.
There are two methods of exceptional preservation that are particularly striking, these are preservation by tar and amber. Tar pits such as those at Rancho La Brea, California are formed when hydrocarbons migrate up through water farming a pool on the surface. Water then accumulates on top of this pool attracting animals to bathe and drink. When an animal enters the pit they become stuck, their struggling then attracts others, both attempting to prey on and aid the stuck animal. Eventually those trapped die due to a combination of exhaustion, drowning, stress and dehydration.
Amber is hardened tree resin. Tree resin form inside trees, when a tree is injured amber flows out of cracks in the bark to seal the break. Insects become trapped in the amber, which then hardens preserving the insect inside the amber. ~SA