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What else can I help you with?
Why do you think most extinction's occur as background extinctions?
Most extinctions occur as background extinctions because they are longer time periods unlike the shorter mass extinctions which there were only two in the Paleozoic era, the Ordovician mass extinction, and the Permian/Triassic extinction in which 95% of all marine animals became extinct
What has caused most of the mass extinctions on earth?
Mass extinctions are caused by rapid, global changes. Usually these are changes in climate. Without the right temperatures and precipitation, plants that animals depend on die out, which wipes out the animals. Examples include the Permian-Triassic Extinction, where volcanoes in what is now Siberia caused intense global warming, wiping out over 90% of species, and the K-T Extinction, where an asteroid impact suddenly blocked sunlight for months or years, killing off the dinosaurs and many other organisms.
Past mass extinctions most likely occurred as a result what?
Sudden changes in environmental conditions.
What age of geologic time ended with the great extinction?
Well, there have been several "great extinctions" in earth's history, but the most recent one was the Cretaceous-Tertiary event, ending the Cretaceous. That was c. 65 million years ago.
What is the animal group with the most extinctions?
invertabates are the animals with the most extinctions
Mass extinctions have only occurred since humans have been present on Earth?
This would be an incorrect premise, the most obvious answer being that Dinosaurs ruled the earth long before humans came along. Dinosaurs are now extinct and that would have been more than a mass extinction, it was global extinction.
Why are mass extinction extremely rare?
That's a tough questions because there are many answers to it. Most rocks are meteors which burns before hitting the earth. There are much fewer meteorites that hits earth before completely burned than meteors but most meteors aren't large enough to wipe out life. There are much fewer dangerous meteorites that could wipe out life on earth than normal meteorites. Fortunately, most dangerous meteorites are very far away from the earth. All the gas giants and black holes draws in most of the dangerous asteroids that could wipe out life. There are much fewer dangerous asteroid that comes near earth than dangerous asteroid that got defeated but most dangerous asteroid that comes near earth won't hit earth and just pass by. There are much fewer dangerous asteroids that hits earth than the dangerous asteroid that pass comes near earth. The dangerous asteroid that hit earth could trigger a mass extinction. Most mass extinctions causes most of the life to be wiped out. Only a very few mass extinctions causes completely all of the life to be wiped out. Mass extinctions only happen a very few time every millions of years, which means after a mass extinction occurs, there won't be another mass extinction for millions of years later. That's why mass extinctions are extremely rare. Frequency Arrangement: Meteors, Meteorites, Dangerous Meteorites (sucked in by gas giants and black holes), Dangerous Meteorites (Come pass by earth), Dangerous Meteorites (Wipes out most life), Dangerous Meteorites (Wipes out completely all life) There have been 5 mass extinctions in the past which is 443.8 million years ago (Ordovician-Silurian), 377.5 million years ago (Late Devonian), 252 million years ago (Permian-Triassic), 201.3 million years ago (Triassic-Jurassic) and 66 million years ago (Cretaceous-Paleogene). Most scientists predicted it's most likely that there will be no more mass extinction in the future. Life will be extinct 5.4 billion years ago when the sun expands into red giant because the expansion of the red giant sun causes the earth's ocean to evaporate, making it uninhabitable for life.
How might extinctions affects the evolution of organisms that survive the event?
The role of mass extinction in evolution. At the most basic level, mass extinctions reduce diversity by killing off specific lineages, and with them, any descendent species they might have given rise to. ... But mass extinction can also play a creative role in evolution, stimulating the growth of other branches.
What is it called in particular when a high percentage of the species on earth dies off at a particular time?
These are called "mass extinctions", and there have been five such events (that we know of) on the Earth. These are generally caused either by astronomical impact events (such as the asteroid that killed off the dinosaurs 65 million years ago) or massive volcanic activity. The causes of these extinctions has been a matter of some dispute, since they happened so long ago.
What is the group with the most extinctions?
This is an interesting question and not one that is easily answered. In terms of the entire history of life on earth the groups of individual species that have been around the longest would have experienced the most extinctions. The more complex the animal the fewer organisms produced and therefore the fewer species available for extinction. This makes various unicelluar organisms (animal, plant and bacterial) subject to the most extinctions. Even though several mass extinctions have occurred, the focus is primarily on the larger identifiable organisms of the time, (Dinosaurs for example), especially those that have a fossil record proving they existed. This places the focus on complex plants and animals. Focus is often on man caused extinctions as well...which are, on the whole, a very small number in the grand scheme of the history of life on Earth. The primary concept to remember is that: Extinction is the rule, NOT the exception.
What impact did asteroids have on earth in the distant past?
There have been several mass extinctions in earth's history, and the most recent one (known as the "K-T event") and possibly one or more of the earlier ones, are believed to have been caused by the impact of a large asteroid, or possibly cometary nucleus.
What planet is most similar to Earth in mass and diameter?
Venus is most similar to Earth in terms of mass and diameter. Venus is almost the same size as Earth, with a diameter about 95% that of Earth, and its mass is about 81.5% of Earth's mass.
