Biology Notes
Biology – Preliminary – Evolution of Australian Biota
1. Evidence for the rearrangement of crustal plates and continental drift indicates that Australia was once part of an ancient super continent
identify and describe evidence that supports the assertion that Australia was once part of a landmass called Gondwana, including: ▪ − matching continental margins ▪ − position of mid-ocean ridges ▪ − spreading zones between continental plates ▪ − fossils in common on Gondwanan continents, including Glossopteris and Gangamopteris flora, and marsupials ▪ − similarities between present-day organisms on Gondwanan continents
Plate tectonics is the study of the movement of crustal plates. The lithosphere consists of the crust and the upper mantle and is divided into several major plates. Plate tectonics provides the evidence that Australia was once part of an ancient super continent.
Alfred Wegner proposed that the continents had once the continents had been united in one large land mass known as Pangaea. He suggested that pangaea broke apart and the continents drifted apart into their present positions. For this reason his hypothesis was called the continental drift hypothesis. Wegner however, was not the first person to suggest the continents had once been joined especially since many scientists noticed the maps of Africa and South America suggested the two continents were once joined together.
There was much opposition to Wegner’s hypothesis but it was later hypothesized by Arthur Holmes that convention currents in the upper mantle moved the continents. However it was not until WWII when scientists began to investigate the topography of the ocean floor that the theory of continental drift became prominent.
Matching Continental Margins
The continental margin is the zone between the ocean basin and the mass of the continent. The continental shelf is the area underwater from the shore to the continental margin. If the continental margins of
1. Evidence for the rearrangement of crustal plates and continental drift indicates that Australia was once part of an ancient super continent
identify and describe evidence that supports the assertion that Australia was once part of a landmass called Gondwana, including: ▪ − matching continental margins ▪ − position of mid-ocean ridges ▪ − spreading zones between continental plates ▪ − fossils in common on Gondwanan continents, including Glossopteris and Gangamopteris flora, and marsupials ▪ − similarities between present-day organisms on Gondwanan continents
Plate tectonics is the study of the movement of crustal plates. The lithosphere consists of the crust and the upper mantle and is divided into several major plates. Plate tectonics provides the evidence that Australia was once part of an ancient super continent.
Alfred Wegner proposed that the continents had once the continents had been united in one large land mass known as Pangaea. He suggested that pangaea broke apart and the continents drifted apart into their present positions. For this reason his hypothesis was called the continental drift hypothesis. Wegner however, was not the first person to suggest the continents had once been joined especially since many scientists noticed the maps of Africa and South America suggested the two continents were once joined together.
There was much opposition to Wegner’s hypothesis but it was later hypothesized by Arthur Holmes that convention currents in the upper mantle moved the continents. However it was not until WWII when scientists began to investigate the topography of the ocean floor that the theory of continental drift became prominent.
Matching Continental Margins
The continental margin is the zone between the ocean basin and the mass of the continent. The continental shelf is the area underwater from the shore to the continental margin. If the continental margins of