Plate Tectonics and the Diversity of Life Life has not evolved on its own; it has evolved on a planet that has experienced changing geology, geography, and climate. Life did not evolve in random patterns, either; in order to understand how life has been affected by its global environment over geological time, we have to look at the relationships between the physical and biological world on which it lives. The Global Diversity Gradient The diversity of life over the globe can be measured by the number of species that occupy a given habitat or area. Many factors affect diversity, including the available energy supply in the area, the number and variety of the different microenvironments that can be occupied by different species, and the severity of the physical environment.
Australia has not always had its present shape or position on the globe. Even today, it is in the process of colliding with South-East Asia. Originally, Australia was joined to a super-continent, referred to as Pangaea meaning 'all lands' in Greekbefore it separated and drifted across the Earth's surface, experiencing a variety of different climatic changes and geological events.
In focusing on Australia's journey across the Earth, it is possible to gain a greater insight into the evolution of Australian landforms, soils, flora and fauna. See image 1 Origins of plate tectonic theory Plate tectonics is a geological theory used to explain the phenomenon of continental drift, which is the tendency of landmasses to move around the Earth.
This theory provides an explanation of how Pangaea was able to break up into two separate landmasses, Gondwanaland and Laurasia, which in turn broke into the seven continents that exist today. See image 2 After Pangaea split into two landmasses, Australia was located on the southern super-continent of Gondwanaland.
Other present-day continents which formed part of Gondwanaland are Africa, Antarctica, South America and some southern parts of the Asian continent. The existence of Gondwanaland was first discovered during the late 19th century by an Austrian geologist named Eduard Suess.
Suess named the ancient landmass after a province in Central India called Gondwana. This was after he discovered that a plant species found in Gondwana matched the fossilised remains of plants found on other continents in the southern hemisphere.
Suess' findings helped to form the theory of plate tectonics. What is plate tectonics? The Earth is made up of many layers. From the outside in, they are the crust, the mantle, the outer core and the inner core. Central to the theory of tectonic plates is the idea that the outermost part of the Earth, the crust, is composed of two layers: The lithosphere is composed of the crust and the solidified uppermost part of the mantle.
The asthenosphere lies underneath the lithosphere, and is made up of the inner viscous part of the mantle. The lithosphere is a more fixed, rigid, cooler substance than the hotter, mechanically weaker asthenosphere. See image 3 The plate tectonic theory hinges upon the principle that the lithosphere exists as separate, distinct tectonic plates, which float on the fluid-like asthenosphere.
Volcanic activity, earthquakes, mountain building and oceanic trench formation occur at the plate boundaries, which are the areas separating the plates. The tectonic plates can be categorised as continental plates or oceanic plates. The Indo-Australian Plate is subdivided into two plates along a low active boundary: The Indo-Australian plate was originally connected to Gondwanaland, and later Antarctica, before it began to drift north some 96 million years ago.
As the continent moved northwards, the climate became drier. As the Australian continent drifted north it developed unique flora and fauna.
The Australian Plate is drifting 35 degrees east of north at a speed of 67 millimetres a year. The easterly side of the Indo-Australian Plate is a convergent boundary with the subducting Pacific Plate.
From the fusing of these two plates, whereby the Pacific Plate slides underneath the Australian Plate, the Kermedac Trench is formed. New Zealand is located at the south-eastern boundary of the plate and was part of Australia before detaching around 85 million years ago.
An old, flat continent Australia has been described as old and flat. This is because the Australian continent has experienced a long period of geological stability, which means there has not been much volcanic or tectonic activity in the recent past. As a result, Australia has been open to the forces of weathering and erosion, which are processes that break apart and move rocks and soil around.
In the distant past, however, there were volcanic eruptions and earthquakes that helped shape the face of Australia. See image 5 Other Chapters. · Plate tectonics is a geological theory used to explain the phenomenon of continental drift, As the Australian continent drifted north it developed unique flora and fauna.
The Australian Plate is drifting 35 degrees east of north at a speed of 67 millimetres a year. The easterly side of the Indo-Australian Plate is a convergent boundary with regardbouddhiste.com · Effect of oil pollution on flora and fauna of the Black Sea. The effects of oil dispersants BP, Finasol ESK and Corexit on the development of herring, Clupea harengus L., plaice regardbouddhiste.com · CONTINENTAL DRIFT, SUPER VOLCANOS, ASTROIDS AND UNDERSTANDING THEIR EFFECT ON SPECIES By Bernard Harrison, Principal Partner, Bernard Harrison & Friends On the land the effects of the impact on the flora and fauna would have been devastating, especially on regardbouddhiste.com Wallace considered the edge of the continental shelf of Asia (the Sunda Shelf) to form the border of this region, and Wallace’s Line is the demarcation, east of Borneo, Bali, and the Philippines, of the “typical” Oriental fauna (Figure 5).
The basis for this division is the striking difference between faunas to the east and west of the regardbouddhiste.com://regardbouddhiste.com · tropics, Part 9 – Climate, flora and fauna J.
F. P. Galvin Met Office, Exeter Much of this series has covered the weather types experienced in the tropics. Following on from the introduction to tropical climates in Part 1 (Galvin, ), this regardbouddhiste.com · As in the case of other natural causes of climate change mentioned here, however, the effects of continental drift is considered to be too small to be a real contributor.
Man-made Causes of Climate Change. Importance of Flora and Fauna; Most Trending regardbouddhiste.com://regardbouddhiste.com