Why was 90% of life wiped out during the cambrian-triassic boundary? Do scientists have any theories?

Answer 1

I am assuming that you are referring to the Permian mass extinction. If so, read below:
Although the cause of the Permian mass extinction remains a debate, numerous theories have been formulated to explain the events of the extinction. One of the most current theories for the mass extinction of the Permian is an agent that has been also held responsible for the Ordovician and Devonian crises, glaciation on Gondwana. A similar glaciation event in the Permian would likely produce mass extinction in the same manner as previous, that is, by a global widespread cooling and/or worldwide lowering of sea level.

Answer 2

if you're referring to what caused the extinction of the dinosaurs during the k-t period then i have the answer. an asteroid. a father and son(both scientists) discovered a strange dust in the k-t boundary while unearthing dinosaur remains. they tracked the dust to a geologically unique area off the yucatan peninsula. pictures where taken of the area and showed that a massive crater lay under the ocean off the coast of the peninsula that was several hundred miles in diameter. the crater is the result of an asteroid collision several millions of years ago, the dust discovered by the father-son duo has been found all over the world smack dab in the k-t boundary. lots and i mean lots of animals would have been incinerated by the blast and the dust would have been kicked up into the upper atmosphere and spread to the four corners due to the trade winds, therefore blocking out the sun and lowering earths temperature enough to kill the remaining animals. only those creatures who were favored by fate lived.

Answer 3

I believe you mean the Permian-Triassic, also known as the great dying:

http://en.wikipedia.org/wiki/Permian-Triassic_extinction_event

This almost ended life on earth. There are multiple theories that have been proposed for this event, however it seems the best explanation is the huge eruption of the Siberian trapts.

This eruption began a series of events which ultimately ended up poisoning the atmosphere and the ocean. It also affected th ozone layer, affecting all surface based life. The oceans became anoxic, killing off most marine life.

~X~

Answer 4

i seen a great show about this on the science channel, scientists believe that vulcanism helped to create a green house gas effect raising the temperature of the earth. the rise in temperature released methane gas from the oceans. there was massive green house effect. a rise in temperature of 10 degrees all over the planet. combined with ash from volcanos and possibly an asteroid impact creating dust in the atmosphere, blocking out the sunlight. this is enough to wipe out almost all life on the planet.

Answer 5

you answered your own question. It's ALL THEORY any intelligent scientist knows the method of theory. and that this is just that. I believe in science but you can't believe something is real based on theory. nothing can be based on this method.So if, what you see you precieve as reality ok?
so how do you get a parrot to talk. Repetition,repititon, and did I mention repitition. how do you get an intelligent person to believe that theory is fact. Repetition of theory without the facts,repetition of theory without the facts,repetition of theory without the facts,repetition of theory without the facts and did I mention repetition of theory without the facts. So theory is just theory call it what it is.

Answer 6

Global warming.

Answer 7

These are not two adjacent periods. Which boundary do you mean?