80M year old bee found preserved in amber
Photo and article courtesy of the American Museum of Natural History


For more than 11,000 years, people have collected, traded, carved, and examined amber; yet much about the substance remains a mystery. For example, no one is certain how amber manages to preserve the organisms entrapped in it (called "inclusions") so exquisitely. It is thought that terpenes, compounds that become linked as the resin hardens, help to preserve the inclusions by dehydrating the organisms and killing any bacteria that might cause decay. Moreover, the organisms' tissues do not shrink as they normally would during the dehydration process; as a result their cellular structure remains intact, making amber inclusions perfect for DNA study.


Amber from the Cretaceous period, 65 to 140 million years ago, when the later dinosaurs flourished, offers some of the earliest glimpses of many life forms. During this period, flowering plants (now the dominant life form on earth) evolved along with bees, moths, and other symbiotic insects. Cretaceous amber, from extinct conifer trees, is brittle and fractures easily. Specimens of amber from the Cretaceous period can be found all over the world, with the largest deposit in Northern Russia. The Middle East has the oldest Cretaceous amber containing insects and other larger organisms. In Kuji, Japan, there are pieces of amber that are 85 million years old. The United States has several Cretaceous deposits, although only in New Jersey is amber found in appreciable quantities. Deposits there range in age from approximately 65 to 95 million years old.
This drawing depicts one of the most important insect fossils, the oldest known bee, Trigona prisca, which is encapsulated in amber from New Jersey. Although it dates from 65 to 80 million years ago, this specimen belongs to a surprisingly recent evolutionary group, raising questions about the corresponding evolution of flowering plants.