Analysing Paleontological and Geological Evidence Flashcards
What is palaeontology?
The study of fossils and extinct life
What is geology?
The study of the origin, history and structure of the Earth as recorded in rocks.
What was the first scientific interpretation of fossils?
Leonardo di Vinci studies mollusc fossils in Italy and concluded that they were buried in marine sediment.
Who proposed the principles of stratigraphy?
Nicolas Steno, in 1669. These laws established rules for relative dating.
What is the law of superposition?
Any undisturbed rock layers will have oldest rocks at the bottom.
What is the law of original horizontality?
All sedimentary strata are deposited horizontally to start with, and will bend due to subsequent tectonic forces
What is the law of cross-cutting relationships?
In any rock sequence, the layer that crosses or intrudes another is the younger rock layer.
What is the law of lateral continuity?
A stratum of rock will be continuous until something disturbs it (erosion or igneous intrusion).
Describe the theory of catastrophism
Early theory on the formation of the earth, changes occurred due to sudden and catastrophic events such as earthquakes and floods.
What discovery did James Hutton and Charles Lyel contribute to?
The theory of gradualism, that changes in the earth’s crust occurred due to slow and progressive causes.
What did the theory of gradualism contribute to?
The creation of the first geological timescale in 1841.
Who discovered radioactivity in 1896?
Henri Becquerel.
How did the discovery of radioactivity contribute to understanding the formation of the earth?
It enabled the establishment of absolute dating methods whereby materials could be given ages in years.
What sources of evidence do scientists draw on to reconstruct past ecosystems?
Proxy data
Fossils
Ice cores
Human evidence - rock paintings
Why is art from ancient humans valuable evidence about past ecosystems?
Humans are artistic by nature, their paintings give scientists clues about when and how the people arrived in the area, the environments at the time, how they lived and adjusted to changes in the climate and landscape, and the effect of climate change on local flora and fauna.
What methods have been used to study Aboriginal rock paintings?
Radiometric dating/ uranium dating to measure the underlying calcite formations.
DNA sequencing of symbiotic bacteria and fungi on the paint.
What region in Australia is rich in Aboriginal rock paintings?
The Kimberly region in northern WA.
What are the two types of paintings int he Kimberly region?
Wandjina and Bradshaw paintings.
What animals do the Aboriginal rock paintings depict?
Australian megafauna including thylacoleo, thylacine and megalania.
What have the Aboriginal rock paintings revealed about the past Australian ecosystem?
There were a series of climate changes. 40,000 years ago, there were lush tropical rainforests, and 10,000 years ago during the ice age, they contracted and were replaced with grasslands. At the end of the ice age, regular monsoon rains returned, and droughts also occurred.
