Iconic Australasian Trees Found as Fossils in South America

by M. R. Carvalho

Summery: 
In this article it reveals the recent discovery of the Agathis tree in South America. This tree was originally found in Australia and later also discovered in Antarctica. Fossil records show that this happened as early as 52 million years ago, when Antarctica and the other countries had the same environments to sustain this tree, which is mountain rainforests where it stays wet and warm all year. These three countries all were all joined together when they were part of the southern supercontinent called Gonwana. The Agathis trees became extinct in Antarctica once the continent broke off and became very cold and icy. The went extinct in South America when the environment started to experience seasonal dryness. The reason that researchers have just found these fossils now is due to the thickness of the rock, which scientists had not been able to penetrate until 1999 even though the sites were found in the 1920's. It still is present in some places of Australia and New Zealand with little human interference.

Connection:
In this unit and our very first unit we studied adaptation and the challenges adaptation faces. In this article it discusses how adaptation can be disrupted by the environment. Because this tree takes so many years to grow and can reach up to 200 feet tall and relies on a specific niche, it has a low adaptation rate. As a result, it has become extinct from two of it's places of origin. It also shows that the growing technological field of human research is improving the ability to find fossils in dense rock. This allows scientists to add to the fossil record, furthering our understanding of the Earth. The last connection that is brought up is having to do with the changing environment due to humans. Deforestation and climate change is having a huge influence over the survival of certain populations. In a study done on similar living relatives of the Agathis in Borneo, the species is being seriously threatened.

Published:The National Science Foundation
URL: http://www.sciencedaily.com/releases/2014/01/140109132650.htm