Beforehumans walked this earth there were five mass extinctions.
Although theCretaceous-Tertiary (or K-T) extinction event is the most well-known because it wiped out the dinosaurs, a series of other mass extinction events has occurredthroughout the history of the Earth, some even more devastating than K-T. Massextinctions are periods in Earth's history when abnormally large numbers ofspecies die out simultaneously or within a limited time frame. The most severeoccurred at the end of the Permian period when 96% of all species perished.
The Permian period,which ended in the largest mass extinction the Earth has ever known, beganabout 299 million years ago. The emerging supercontinent of Pangaea presentedsevere extremes of climate and environment due to its vast size. The south wascold and arid, with much of the region frozen under ice caps.
This along with K-T aretwo of the Big Five mass extinctions, each of which wiped out at least half ofall species.
The Miocene Epoch was characterized by major global climatic changes that led to more seasonal conditions with increasingly colder winters north of the Equator. (This puts the climate change debate to bead)
The earth went from theOligocene through the Miocene and into the Pliocene, with the climate slowlycooling towards a series of ice ages.The Miocene boundaries are not marked by a single distinct global event butconsist rather of regional boundaries between the warmer Oligocene and thecooler Pliocene Epoch.
https://en.wikipedia.org/wiki/Miocene
An ice age isa period of long-term reduction in the temperature of Earth's surfaceand atmosphere, resulting in the presence or expansion of continental andpolar ice sheets and alpine glaciers.Within a long-term ice age, individual pulses of cold climate are termed "glacial periods" (or alternatively "glacials"or "glaciations" or colloquially as "ice age"), andintermittent warm periods are called "interglacials".In the terminology of glaciology, ice age implies the presence ofextensive ice sheets in both northern and southernhemispheres.[SUP][1][/SUP]By this definition, we are in an interglacialperiod—the Holocene—ofthe ice age. The ice age began 2.6 million years ago at the start of the Pleistocene epoch, because the Greenland, Arctic,and Antarctic icesheets still exist
Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by massextinction events. Over 99% of all species[SUP][32][/SUP] thatever lived on Earth are extinct.[SUP][33][/SUP][SUP][34][/SUP]
https://en.wikipedia.org/wiki/Earth
The next well-documented iceage, and probably the most severe of the last billion years, occurred from 850to 630 million years ago
(the Cryogenian period) and may have produced a Snowball Earth in The Snowball Earth hypothesis proposes that Earth'ssurface became entirely or nearly entirely frozen at least once, sometimeearlier than 650 Mya (million years ago).
which glacial ice sheetsreached the equator,[SUP][33][/SUP] possibly being ended by the accumulation of greenhouse gases such as CO[SUB]2[/SUB] produced by volcanoes.
"The presence of ice on the continents and pack ice on the oceans would inhibit both silicateweathering and photosynthesis, which are the two major sinks for CO[SUB]2[/SUB] atpresent."[SUP][34][/SUP] It has been suggested that the end of this ice age wasresponsible for the subsequent Ediacaran and Cambrianexplosion, though this model isrecent and controversial.
https://en.wikipedia.org/wiki/Ice_age#Glacials_and_interglacials
I will get to the point later. I have to go
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Although theCretaceous-Tertiary (or K-T) extinction event is the most well-known because it wiped out the dinosaurs, a series of other mass extinction events has occurredthroughout the history of the Earth, some even more devastating than K-T. Massextinctions are periods in Earth's history when abnormally large numbers ofspecies die out simultaneously or within a limited time frame. The most severeoccurred at the end of the Permian period when 96% of all species perished.
The Permian period,which ended in the largest mass extinction the Earth has ever known, beganabout 299 million years ago. The emerging supercontinent of Pangaea presentedsevere extremes of climate and environment due to its vast size. The south wascold and arid, with much of the region frozen under ice caps.
This along with K-T aretwo of the Big Five mass extinctions, each of which wiped out at least half ofall species.
The Miocene Epoch was characterized by major global climatic changes that led to more seasonal conditions with increasingly colder winters north of the Equator. (This puts the climate change debate to bead)
The earth went from theOligocene through the Miocene and into the Pliocene, with the climate slowlycooling towards a series of ice ages.The Miocene boundaries are not marked by a single distinct global event butconsist rather of regional boundaries between the warmer Oligocene and thecooler Pliocene Epoch.
https://en.wikipedia.org/wiki/Miocene
An ice age isa period of long-term reduction in the temperature of Earth's surfaceand atmosphere, resulting in the presence or expansion of continental andpolar ice sheets and alpine glaciers.Within a long-term ice age, individual pulses of cold climate are termed "glacial periods" (or alternatively "glacials"or "glaciations" or colloquially as "ice age"), andintermittent warm periods are called "interglacials".In the terminology of glaciology, ice age implies the presence ofextensive ice sheets in both northern and southernhemispheres.[SUP][1][/SUP]By this definition, we are in an interglacialperiod—the Holocene—ofthe ice age. The ice age began 2.6 million years ago at the start of the Pleistocene epoch, because the Greenland, Arctic,and Antarctic icesheets still exist
Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by massextinction events. Over 99% of all species[SUP][32][/SUP] thatever lived on Earth are extinct.[SUP][33][/SUP][SUP][34][/SUP]
https://en.wikipedia.org/wiki/Earth
The next well-documented iceage, and probably the most severe of the last billion years, occurred from 850to 630 million years ago
(the Cryogenian period) and may have produced a Snowball Earth in The Snowball Earth hypothesis proposes that Earth'ssurface became entirely or nearly entirely frozen at least once, sometimeearlier than 650 Mya (million years ago).
which glacial ice sheetsreached the equator,[SUP][33][/SUP] possibly being ended by the accumulation of greenhouse gases such as CO[SUB]2[/SUB] produced by volcanoes.
"The presence of ice on the continents and pack ice on the oceans would inhibit both silicateweathering and photosynthesis, which are the two major sinks for CO[SUB]2[/SUB] atpresent."[SUP][34][/SUP] It has been suggested that the end of this ice age wasresponsible for the subsequent Ediacaran and Cambrianexplosion, though this model isrecent and controversial.
https://en.wikipedia.org/wiki/Ice_age#Glacials_and_interglacials
I will get to the point later. I have to go
-
What's "later" to you?
Some of us here are waiting for part two...
And we ain't got all day...
