EnviroKids October 2018 Issue

Digging Up The Past...

Big Words for Big Jobs A person who studies dinosaurs is called a Palaeontologist . Palaeoanthropol- ogists study hominin (primate groups, which include our ancestors and our- selves) and evolution. Archaeology is the study of remains related to ancient

peoples, including cultural items (tools, orna- ments, art, etc) and their food (bones, shells and other preserved resources), which tell us about their behaviour. Palaeobotany is the branch of palaeontology that deals with the recovery and identification of plants. Archae- ozoology studies remains related to ancient people including items left behind when an animal dies, including bones and shells.

Local Discoveries

A new species of human relative named Homo naledi was discovered in 2015. The expedition team found more than 1550 identi- fied fossil elements (the single larg- est fossil hominin find made on the continent of Africa).

Our oldest fossils are the remains of ancient plants and animals that lived millions of years ago, preserved in layers of rock. They are important because they provide us with a picture of what life was like in the past.

What's it like to be an Archaeozoologist? Dr Graham Avery was introduced to archaeolo- gy by his Grade 7 teach- er, who brought artefacts into a lesson. “He men- tored me and I collected stone tools, which was al- lowed in those days.” The inspiration stuck, and Dr Avery obtained his Mas- ter of Arts and PhD at the University of Cape Town. “Excavations were usually

What are Fossils?

There are two main types of fossils. They are body fos- sils and trace fossils. Body fossils are the preserved body parts of an organism such as bones, shells, leaves, stems and seeds. Body fossils tell us a lot about what the animal or plant looked like. We can also work out what kind of food it ate from its jaw structure, what senses it used most, the size of its brain, its defense mechanisms, and much more. Trace fossils are the signs of life that have been preserved. They give evidence that organisms once lived on Earth but are not made up of parts of the organism itself. Examples include footprints, droppings or leaf impressions. Fossils vary in their degree of mineralisation and pet- rification. An example of ancient petrified fossils can be found in the hard rocks of the Karoo formations. In more recent re- mains, normal bone composition is replaced by minerals such as iron and phosphate, for example in the West Coast Fossil Park, Elandsfontein and the Vaal Gravels.

Cango Caves in Oudtshoorn, Western Cape

Where can fossils be found?

over two to three weeks , but could be up to two months long. Then the time-consuming work of processing the material started. A day might include all or some of the following: iden- tification of categories of cultural items and/or food species, labelling and recording items in collection databases, counting the results before statistical analysis, interpretation and write up for publication in scientific journals or articles for the pub- lic.” Dr Avery worked in a museum, so there was also some ad- ministration, writing funding proposals, assisting students and researchers, answering queries from members of the public and involvement in the Museum’s exhibition, school education and other public programmes. "Being able to do what I enjoyed was a constant high- light of my research career. I shifted my focus from stone tools to the role of shellfish, birds and mammals in the diets and be- haviour of past humans (archaeozoology) and was able to be- come competent in biological disciplines I’d previously had no training in. In retirement, my research continues and I mentor younger archaeological and palaeontological colleagues and assist scientists and post-graduate students in identifying the prey of raptors and carnivores they are studying.

Most fossils are found in sedimentary rock. This rock is formed when layers of erod- ed earth are deposited on top of each other. The process by which sedimentary rocks are formed is delicate enough that fossils can be preserved within them. How were fossils formed? Fossils were made when living things died and got buried quickly before the hardest parts of the animal had a chance to decay. Over thousands of years, more and more layers of sand and mud settled on top of the animal. All these layers caused pressure which made the skeleton harden into rock. Over time, the rock surrounding the fossilised skeleton is eroded by wind and water.

Photo credit: National Geographic

Coelacanths (pictured below) were thought to have become extinct in the Late Cretaceous period (around 66 million years ago) but were rediscovered in 1938 off the coast of South Africa.

Did you know? The human skull is made of 22 bones.

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