L1: Introduction to palaeobiology Flashcards
What is palaeontology?
The study of fossils and the evolution of life on earth
In what type of rock do fossils occur?
Sedimentary rock
What percentage of rock on earth is sedimentary?
75%
In what ways are fossil specimens analysed?
Synchtron and CAT scanning, finite state analysis, geochemical analysis
What was believed about fossils pre 1750s?
Thought that fossils were inorganic, rather than the remains of living things
How old is the earth?
4.6 billion years old
Who discovered the masterdom dinosaur?
Thomas Jefferson
Who proposed the theory of speciation in 1859 and what is it?
Darwin and Wallace, the evolutionary process by which populations evolve to become distinct species
What did Darwin beleive about the course of evolution after studying the stratigraphy of a cliff?
Saw a new species appearing in each layer and proposed that speciation occurred by gradualism
What is gradualism?
the hypothesis that evolution proceeds chiefly by the accumulation of gradual changes and that speciation is slow and gradual and uniform
What is Neo-darwinian evolution?
Theory of evolution that represents a synthesis of Charles Darwin’s theory in terms of natural selection and modern population genetics.
When were the mechanisms of plate tectonics realised?
In the 1960s
What is the punctuated equilibrium model?
Theory proposing that once a species appears in the fossil record, the population becomes stable, showing little evolutionary change for most of its geological history, occurs at the population level, not species level
How do the ideas of gradualism and punctuated equilibrium (PEM) differ?
Theories go against each other, the PEM means that a species will speciate rapidly then undergo a period of stasis, and works on a small isolated population, rather than a slow change throughout the species over time.
What is the cladistics revolution?
Occurred in the 1970s, organisms now categorised into clades based on their most recent common ancestor
What did the presence of Iridium in the rock layer indicate?
The element is not naturally found on earth so must have been a meteorite strike. Dates of the rock coincided with a loss of many species in the cretaceous, so was determined that this was a mass extinction
When did the major mass extinctions occur?
End Ordovician Late Devonian End Permian End Triassic End Cretaceous
What is an icehouse earth?
Occurs when there are ice sheets permanently at both poles, like in an ice age, global temperatures on average cooler
What is a greenhouse earth?
A period when there are no continental glaciers whatsoever, temperatures are generally much warmer
What is palaeobiology?
The biology of fossil animals and plants
What are the different types of fossils found?
Trace Soft tissue Gastroliths Coprolites Eggs Feathers Bones Teeth
What are trace fossils?
A geological record of ancient biological activity, such as footprint tracks or burrows
What can we work out about a dinosaur by looking at its tracks?
The speed it travelled at, how they walked, whether they lived in herds or are solitary
What are soft tissue fossils?
When the parts that normally decay are preserved, by exceptional preservation, such as skin. This is very rare
