A few thoughts on Mass Extinctions [ 2003 ]

NASA Astrobiology Institute / SpaceRef ^ | February 21, 2003 | Madalyn Edwards and Daniella Scalice

[SunkenCiv]

Officially there have been five big mass extinction events over the past 540 million years. What is often not mentioned is that up to five other mass extinctions occurred between 650-500 million years ago. These little publicized events mainly involved microorganisms, and marine animals and plants. They each took place before the Cambrian Explosion (between 543 and 490 million years ago) during which time life forms on Earth exploded into previously unseen levels of diversity... The Earth has not seen the same type of diversification of life forms since the Cambrian Explosion, so the percentage of species lost with these five main extinction events is quite stunning. Between 75-95% of all species were lost with each extinction event... One big question is whether there is a cyclical pattern to mass extinction events. Within the fossil record - an incomplete script at best - there appears to be a pattern that suggests mass extinction events occur every 26-30 million years. This pattern is thought to be related to celestial objects such as comets and meteors which have long been known to travel distinct paths on very dependable timetables. This could imply that there have been possibly up to 23 mass extinction events since life first evolved on Earth!

[SunkenCiv]

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[SunkenCiv]

This is a GGG and Catastrophism topic; I didn't ping the GGG list, but pinged the C list instead -- just to be confusing, causing chaos and cataclysm.

To all -- please ping me to other topics which are appropriate for the GGG list. Thanks.

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[muawiyah]

Gad!!!!!!!

[SunkenCiv]

See?