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here is the link to it

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Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.

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You're off to a great start! Keep this box and I will write my feedback here each time I check your work :)

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The ocean formed approximeatly 3.800 million years ago. You can say 3.8 billion years ago too.
So you can basically say that when the Mesproteozoic era existed or when it was that time period, water already existed. Since the mestproteozoic era existed around 1600 million years ago or 1.6 billion years ago.

Since earth didnt look like today, it moved around and there was bigger oceans than now.
Picture of precambrian era:
https://www.google.com/search?q=earth+during+precambrian+era&rlz=1CAQIMT_enSE834&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj6-vCHkpDgAhWsiKYKHS6zDmQQ_AUIDigB&biw=1242&bih=540&safe=active&ssui=on#imgrc=2jsH5ppMTeULdM:

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Submitted by Aaron Cavosie, University of Puerto Rico

Why is this question important?

Most of us teach earth science using simple or sophisticated models and imagery that demonstrate to students that the Earth is essentially a blue marble whose surface is dominated by oceans. This vision of a blue Earth has even been espoused by popular science writers such as the non-fiction work 'Pale Blue Dot' by the late Carl Sagan. For many it would be difficult to envision an Earth without its blue blanket of oceans. However this is precisely what the early stages of our planet were like. An ocean-free Earth existed, perhaps for several hundred million years as a consequence of extremely high surface temperatures following planetary accretion. The formation of oceans on Earth represents no less than a global-scale cooling of Earth's surface to temperatures at which water is stable as a liquid phase.

That such a profound transition occurred from the highly energetic conditions of the newly accreted Earth whose surface was dominated by meteorite impacts and transient magma oceans to cooler conditions capable of supporting liquid water and eventually life is not in question. However, the timing of this transition - which has implications for when surface conditions necessary for the development were established - is poorly known. Part of the uncertainty of the timing of this transition is due to the fragmentary nature of the rock record for the first ~500 million years of Earth history. Simply put, not much is preserved in the rock record for this time. It is the 'not much' part of the rock record that hold the clues however. The most promising information has come in two forms: (1) preserved sediments up to ~3800 million years old and (2) oxygen isotope studies of detrital zircons up to 4400 million years old.

So what does the rock record tell us?

What we know...

The rock record: Isua BIF

The oldest known rocks on Earth are almost exactly 4 billion years old and are comprised of metamorphosed and deformed granitoids from northwestern Canada collectively called the Acasta gneiss. Direct radiometric dating using the U-Pb method on zircons has demonstrated that these rocks crystallized 4030 million years ago. However, these 'oldest rocks' do not record information on surface conditions at the time of their formation. The oldest direct evidence for the presence of surface waters are slightly younger ca. ~3800 million years old sedimentary rocks called banded iron formation (BIF) that are exposed in southwest Greenland at a location called Isua. The very existence of the Isua BIF requires the presence of stable surface water, at least locally for the chemical deposition of the sedimentary components at ca. 3800 Ma. These rocks were deposited in a somewhat analogous way to how limestones or cherts are deposited directly from seawater in modern marine environments.

The mineral record: Detrital zircons

The oldest known Earth materials are actually not rocks. Sand grains comprised of the mineral zircon (ZrSiO4) have been discovered that are almost 400 million years older than the oldest rocks in the rock record. In the Jack Hills of Western Australia detrital igneous zircons with U-Pb crystallization ages as old as 4400 million years occur in Archean clastic sediments deposited at ~3000 Ma. Zircon is a very useful mineral that is mechanically resistant to erosion, chemically resistant to fluids, and can be 'dated' with the U-Pb method owing to the ubiquitous presence of trace amounts of radioactive U and Th that are incorporated in most zircons at the time of crystallization. The very existence of these ancient zircons demonstrates that igneous rock (e.g. crust) was present starting at ca. 4400 Ma. But the evidence of oceans preserved in these grains comes in a different form.

Oxygen isotopes in geologic materials are affected by temperatures present during the formation and alteration of rocks and minerals. In basic terms the oxygen isotope ratio- the ratio of 18O-to-16O (usually expressed in a notation called 'delta', or δ18O, and reported relative to a standard material) of minerals from the mantle varies little due to the high temperatures in the mantle, and is usually around a value of ~5.5‰ (per mil or parts-per-thousand relative to a reference material). In contrast the δ18O composition of surface materials (e.g., minerals and rocks) varies much more widely and can range from values similar to mantle minerals if unaltered (e.g. 5-6‰) up to values of δ18O = >30‰ due to low temperature reactions of minerals with fluids, such as surface waters like oceans. In simple terms mantle materials have 'low' δ18O values, while sediments and other low-T altered materials have 'high' δ18O values.

Analysis of oxygen isotope ratio in zircon can address the nature of the reservoir of oxygen in the magma that is adopted by the zircon during crystallization. In other words δ18O(zircon) provides a reliable record of whether the parental δ18O(magma) was 'mantle-equilibrated' as all primary mantle-derived magmas are prior to interaction with crustal materials, or whether the parental δ18O(magma) was 'crustal' meaning that the magma inherited a component of its oxygen budget from assimilated crustal materials (like sediments or other altered rocks) which results in higher δ18O values in the bulk rock and constituent igneous minerals.

To address our question of when oceans first formed on Earth we can investigate the δ18O values of the ancient zircons to see if they record 'mantle-equilibrated' values, meaning no evidence of a crustal component is detectable in the oxygen or if they record 'crustal' δ18O values meaning that the early magmas assimilated crustal materials that were affected by low-temperature interaction with water prior to melting. Because we can also 'date' the zircon grains, we can place these conditions in a temporal context. What we find is that the oxygen isotope ratios (δ18O) in the oldest detrital igneous zircons record mantle-equilibrated values from 4400 to ~4325 Ma (e.g. ~5.3 to 5.4‰). From 4325 to ~4200 Ma the δ18O values of zircons are slightly elevated up to 6.3‰ (Note: the upper end of this range ~6.3‰ is higher than what is capable of being produced in a mantle melt, however the uncertainty in these analyses overlaps with the mantle). Just after 4200 Ma the story changes. Values of δ18O in the igneous zircons reach values as high as 7.3‰ with uncertainties that exclude a mantle source. We infer that to produce these 'high δ18O' zircons required that the igneous protolith of the zircon must have assimilated or re-melted crustal materials that were altered by low-temperature processes at or near Earth's surface. In other words, surface waters were present by at least 4200 Ma.

What does all this mean? There are now two hypotheses for when oceans originated on Earth.

Hypothesis 1: Oceans first formed at ca. 3800 Ma. The Isua BIF provides definitive 'ground truth' that surface water was indeed stable at 3800 Ma, however no 'boundary condition' can be defined by the Isua BIF. Simply put there is no way to determine if the Isua BIF was deposited in the first ocean on Earth. In that regard the Isua BIF is akin to a geologic 'snapshot'; we can't infer that water existed before the Isua BIF.

Hypothesis 2: Oceans formed much earlier by at least ca. 4200 Ma. The Jack Hills detrital zircons provide an actual timeline that records the magmatic oxygen isotope compositions of magmas on the young Earth. In this record, we can see a time before the influence of low-temperature weathering was recorded in magmas prior to ~4200 Ma and a definitive change in magmatic oxygen as recorded in elevated ?18O (zircon), after 4200 Ma. In this regard, the detrital zircons actually record a boundary condition that marks when surface weathering, and hence the presence of oceans, occurred.

How to link this topic to the classroom

Teach students that we are just NOW starting to write the first chapter of Earth history - that there are lots of exciting areas of research that they can participate in.

Create a better vision of the early Hadean - how long was the Earth 'Hell-like'

Challenge the assumption of permanent oceans on Earth (compare with 'Snowball Earth' conditions later in the Precambrian)

Comparison of Earth with the other terran planets (Mercury, Venus, and Mars) implications of oceans on Europa (Europa is a Moon of Jupiter covered in ice but likely with a liquid water ocean)

Increase knowledge and awareness of BIF (the source of most economic iron deposits known only from the Precambrian)

Recognition that the rock record is not complete (not perfect); raise awareness of the older 'mineral record'

Raise awareness of how 'chemistry' and 'geology' are intimately associated in 'geochemistry'.

References and other Resources

Cavosie A.J. Liu D. Wilde S.A. Weiblen P.W. Valley J.W. 2004 Internal structure and U-Th-Pb chemistry of Jack Hills detrital zircons: a mineral record of Early Archean to Mesoproterozoic 4348-1576 Ma magmatism. Precambrian Res. 135 251-279.

Cavosie A.J. Valley J.W. Wilde S.A. E.I.M.F 2005 Magmatic 94818O in 4400-3900 Ma detrital zircons: a record of the alteration and recycling of crust in the early Archean. Earth Planet. Sci. Lett. 235 663-681.

Nutman A.P. 2006 Antiquity of the oceans and continents. Elements 24 223-228.

Valley J.W. Lackey J.S. Cavosie A.J. Clechenko C.C. Spicuzza M.J. Basei M.A.S. Bindeman I.N. Ferreira V.P. Sial A.N. King E.M. Peck W.H. Sinha A.K. Wei C.S. 2005 4.4 billion years of crustal maturation: oxygen isotope ratios of magmatic zircon. Contrib. Mineral. Petrol. 150 561-580.

Valley J.W. 2006 Early Earth. Elements 24 201-204.

Return to Key Questions about the Early Earth index page

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teach the earth:teaching topics:early earth

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Submitted by Aaron Cavosie, University of Puerto Rico Most of us teach earth science using simple or sophisticated models and imagery that demonstrate to students that the Earth is essentially a blue marble whose surface is dominated by oceans.

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What do the fossil records say about your time period

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What do the fossil records say about your time period

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The fossils in this time period doesnt say much about it. If we refer to the era that was two eras ago, we would have the first/oldest known fossil. I cant find any good pictures of fossils from this era, but they do look pretty simular to the oldest known ones. I mean i can barely tell the difference

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How did the environment of the Earth during your time period shape the forms of present life

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How did the environment of the Earth during your time period shape the forms of present life

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During this era there was only fossils. Bacteria hadnt formed and there was only rocks and mountains. I dont know how the enviroment then would change anything now. The only thing that gets on my mind is the rocks. And ofcourse the fossils, not that i know what its used for.

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The atmosphere was created around the first 500 million years (about 4500 million years ago).  According to this site, "1 billion years ago (1000 million years ago) early aquatic organisms called blue-green algae began using energy from the Sun to split molecules of H2O and CO2 and recombine them into organic compounds and molecular oxygen (O2)". Around this time, oxygen levels on earth were rising.

To a conlusion, atmosphere did exist during this time period, but it was not breathable. You could not use it as we use it today.

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There was a supercontinent named Rodinia that occurred at the same time as the Mesoproteozoic era took time. The rodinia supercontinent did go on after the mesproteozoic era was done, but that doesn't mean that it looked the same. It looked different every other million years.
It always formed into a big landscape and then it just broke up together, over and over. Rodinia is believed to have formed about 1 billion years ago (The time where Mesoproteozoic era started to end) and would have covered most of the Earth's existing crust. It is believed that the supercontinent broke up to eight continents about 750 million years ago.

Before the Rodinia supercontinent occured, there was another supercontinent. That supercontinent is called Columbia supercontinent.
The supercontinent Columbia broke up in the beginning of this era. After a time supercontinent Rodinia came.

The last super major events that occured was the evolution of sexual reproducion.

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What were the apex predators during your time period

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What were the apex predators during your time period

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Scientist does not know when predators actually came to earth. Scientist have found teeth from about 500 mya,  they are not sure but predators could have existed before the 500 mya mark.

Base fact. According to biologists  "predation must involve the death of one living thing at the hands (or teeth, or claws) of another". A predator could be a Weasels, hawks, wolves, mountain lions, and grizzly bears. In swedish its called a "rovdjur". e

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Around the world right now, thousands of animals are about to die. The game is up for untold numbers of deep-sea fish, mountain-dwelling hares, subterranean earthworms and high-flying songbirds. They are all seconds away from becoming dinner for predators like lions, eagles and sharks.

But when did this carnage begin? Have predators stalked the Earth since the origin of life itself? Or was our primordial planet once a Garden of Eden where species lived in peaceful co-existence?

The truth is, no one actually knows for sure. But evolutionary biologists have learned enough about the history of life on Earth to begin the hunt for the first predator. Their work suggests it was about as far removed in appearance from today's killers as it's possible to imagine.

Before we pick up the trail, it might help to spell out what a predator is. According to most biologists, predation must involve the death of one living thing at the hands (or teeth, or claws) of another, which has to gain some nutritional benefit from the kill. A lion is a predator because it kills and eats a gazelle, but the gazelle is not a predator, because it doesn't have to kill the grasses it eats.

Predators can kill without inflicting physical injury

What sort of traces would the first predator have left behind? We often think of predators using jaws and sharp teeth to rip chunks out of their prey, so maybe we should look for the oldest jaws and teeth. In fact, just last year, we learned that modern vertebrate jaws date back 420 million years and that teeth appeared 500 million years ago.

But predators can kill without inflicting physical injury. Think of the predatory pitcher plants that trap, drown and devour insects. So if predators don't need teeth and jaws, they might have appeared long before the 500-million-year mark.

It turns out they really did. Palaeontologists have collected fossils of predators that existed tens of millions of years before teeth evolved. These predators date right back to the first abundant animal life, about 540 million years ago.

They are known collectively as the anomalocaridids, a name that translates as "abnormal shrimp". It's well chosen: the anomalocaridids were odd-looking marine animals that to our eyes seem to have been cobbled together from bits of various different species. They grew up to 2 m (6ft) in length, and had good eyes and a pair of dextrous graspers near their mouth. They may have lacked teeth and jaws but they were undoubtedly terrors of the seas they occupied.

"Anomalocaridids are the earliest 'mega-predator'," says Lindsey Leighton at the University of Alberta in Edmonton, Canada.

Originally palaeontologists thought a hunting anomalocaridid would have used the formidable ring of plates around its mouth to crush its prey. But disappointingly, an analysis a few years ago suggested that these plates were too weak to crush anything. The anomalocaridids may actually have used their mouths to suck up soft worms from the muddy ocean floor.
To crush or to suck?
But were these worm-sucking anomalocaridids the original predators? In July 2014, we learned something new that helps answer the question. An exceptionally well-preserved fossil revealed that, for all their sophisticated appearance, anomalocaridids had simple brains. What's more, other well-preserved fossils from the same time period show that the animals living alongside the anomalocaridids - including some that the predators might have eaten - had relatively complex brains in comparison.

This actually fits with what we know about today's predators, says Nicholas Strausfeld at the University of Arizona in Tucson, who helped describe the anomalocaridid brain. "There are many extant examples of what can be considered small-brained species preying on others that have larger brains," he says. This shows that predatory behaviour can occur in relatively simple species: the kind that existed before the anomalocaridids evolved.

"We subconsciously tend to think of predators as advanced, probably because we envision them at the top of the food web," says Leighton. But predatory behaviour may be among the first feeding strategies to appear in ecosystems. "Actually, herbivory [plant-eating] tends to show up much later."

In fact, there is evidence that predators existed before the anomalocaridids. Animals first began to grow hard shells and exoskeletons about 550 million years ago. Some of the fossils of these earliest exoskeletons are punctured with circular holes about 0.4 mm across. These are almost certainly marks left by predators that bored through the tough armour to feast on the soft tissue hidden within.

The borings are all similar in shape, which suggests they were made by a single predatory species. We don't yet know what it looked like. But the borings it made are currently the earliest good evidence for relatively large predators, says Leighton. That makes the mystery species responsible a much better candidate for the title of first predator than the anomalocaridids.

The Ediacarans escaped the attention of predators, simply because there weren't any

A look at slightly older rocks and fossils strengthens the case. Between about 575 and 540 million years ago the world was occupied by a peculiar collection of organisms that have been labelled the Ediacaran biota. The Ediacaran organisms were large - some were over 1 m (3 ft) long - soft-bodied, and mostly incapable of movement. They should have been torn to shreds by predators, but they weren't.

In the 1980s, Mark McMenamin at Mount Holyoke College in South Hadley, Massachusetts suggested that the Ediacarans escaped the attention of predators simply because there weren't any - or at least, none large enough to pose any real threat. These ecosystems may have been peaceful live-and-let-live worlds in which each Ediacaran used photosynthesis to meet its own energy needs. McMenamin dubbed his idea "the Garden of Ediacara".

In the 30 years since, geologists have found little evidence that large predators were active during the Ediacaran period. That suggests McMenamin's ideas may be correct. If they are, we have identified the point in geological time - about 550 million years ago - when large predators first appeared.

But not all predators are large. The world of microbes is teeming with tiny killers. They might be too small to inflict damage on something the size of an Ediacaran, but these predators can still wreak havoc at the microscopic scale - and they were doing so long before the Ediacarans evolved.

A decade ago, Susannah Porter at the University of California Santa Barbara and her colleagues discovered tiny fossilised amoebae in 740-million-year-old rocks near the bottom of the Grand Canyon. The amoebae had developed tough skeletons, just like big animals did 550 million years ago did when large predators appeared.

It seems that at least some of the amoebae grew their skeletons for a similar, defensive reason. Several of the fossils carried semi-circular borings about 20 micrometres wide. These were probably the marks left by some unidentified predatory microbe that punctured the tough skeletons to feed on the nutrients within, rather like vampire amoebae do today.
Teeny tiny miniature predators
In the same way that the borings in the 550-million-year-old animals are the earliest strong evidence we have that big predators had evolved, the borings in the 740-million-year-old microfossils are the earliest good evidence of tiny predators.

But they probably don't signify the moment when predatory behaviour first evolved. More likely they show us when micro-predators began to attack complex microbes, like amoebae, that could evolve hard skeletons in response. Simpler microbes, like bacteria, might have been attacked by micro-predators much earlier in Earth's history, but without ever evolving a defence strategy that can be easily identified in the fossil record.

In other words, micro-predation probably predates these 740-million-year-old fossils. So we will need a different way to study it.

One approach is to look at the predatory strategies that microbes use today. The most well-known is called engulfment: a relatively large microbe swims up to a smaller cell and swallows it whole. Look at these microbial engulfers, though, and a pattern soon emerges. They are almost all "eukaryotes", the group that includes big organisms like animals and plants, as well as microbes like the amoebae. Engulfers seem to be absent from the other great branch of the tree of life, the prokaryotes, which include all the bacteria.

Some prokaryotes force their way into larger cells

No one knows for sure when the eukaryotes first evolved, but the general consensus is that they came after the prokaryotes, around 2 billion years ago. So perhaps engulfment, and predation, began with those first eukaryotes. This would imply that the earlier, prokaryotic-only world was a predator-free zone.

That seems to fit with what we know about living prokaryotes. "There are no real prokaryote predators today," says David Penny at Massey University in Palmerston North, New Zealand.

Or are there? It's true that prokaryotes seem to be incapable of engulfment, says Edouard Jurkevitch at the Hebrew University of Jerusalem in Rehovot, Israel. But they can use other strategies to prey on cells in their environment. Some prokaryotes force their way into larger cells and digest them from the inside, says Jurkevitch. Others latch onto the side of cells and consume them from the outside. Some even team up with other prokaryotes to form hunting packs that can target entire microbial colonies.

The general consensus is that prokaryotes first appeared about 3.5 billion years ago. Perhaps some of them were predatory. "The roots of predation (and parasitism) may be very ancient," says Jurkevitch.

Penny's research backs this conclusion. A few years ago, he decided to test whether life could have enjoyed a peaceful Garden of Eden-style existence before eukaryotes appeared. He ran computer simulations to see how the first populations of cells would have evolved 3.5 billion years ago, assuming they obeyed a few fundamental biological principles. His results suggest that predation is too good a strategy not to evolve rapidly, although predators will usually be heavily outnumbered by organisms that make their own energy.

We don't know what the very first life was like

"It did seem that predation was an inevitable outcome of the principles," says Penny. "Predation appeared within a thousand or so generations."

Penny's theoretical work, and Jurkevitch's observations of prokaryotes today, suggest that there were predators on Earth 3.5 billion years ago, very soon after prokaryotic cells first appeared. So have we finally identified the very first killers? After all, before prokaryotes appeared there was no cellular life at all. We don't know what the very first life was like, but it may have been a loose collection of complex organic chemicals floating in solution. These probably included nucleic acids similar to DNA, such as RNA.

Remarkably, though, some researchers think predators might have lurked even in this pre-cellular world of chemical replicators.

About 15 years ago Thomas Cavalier-Smith at the University of Oxford suggested that these nucleic acid communities were a kind of simple ecosystem. Today, some nucleic acids act as catalysts that break up other molecules. Cavalier-Smith reasoned that they probably existed in the pre-cellular communities too. Some of them would have latched onto other nucleic acids and broken them apart, effectively attacking and destroying them to fuel their own growth and replication. In other words, these molecules would have behaved as predators.

Armen Mulkidjanian at the University of Osnabrück in Germany, who studies the origins of life, says the idea is reasonable. It's more common for researchers to call this behaviour parasitic, he says. "But parasitic behaviour, generally, should include predatory behaviour."

The biggest hurdle of all is to picture the predators in the primordial soup

If Cavalier-Smith is right, then these catalytic nucleic acids really were the very first predators. Go back to the time before they existed and there was no life of any sort, so by definition there can have been no predators.

From our position as large animals, it's easy to lose perspective on life's history on Earth. Think predators and the first thing that springs to mind might well be a pride of lions or a pack of wolves. It's a big mental leap from these modern killers to the worm-sucking anomalocaridids and the enigmatic predators that patiently drilled their way through defensive armour over half a billion years ago.

But even that leap is easy compared to the jump we have to make to recognise predators among prokaryotes. And the biggest hurdle of all is to picture the predators in the primordial soup that existed before cellular life. If they existed, they might not have looked particularly fierce, but those killer molecules are hugely significant. They suggest that from its very inception, life has been troubled by predators intent on causing death.

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What was Earth's first predator and when did it live?

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Around the world right now, thousands of animals are about to die. The game is up for untold numbers of deep-sea fish, mountain-dwelling hares, subterranean earthworms and high-flying songbirds. They are all seconds away from becoming dinner for predators like lions, eagles and sharks. But when did this carnage begin?

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What were the dominant species during this time period

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What were the dominant species during this time period

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There was no dominant species during this era. Right after this era comes the first multicellular life. So to sum it down. In this era there was no dominant species because no "life" had actually formed yet, only modern plants (if that counts) and fungi. At this point they were called small single-celled organisms.

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There was not so much "geographic landscape" during this era. It was moslty rocks as earth still formed into what it is today. Mountains formed but they breaked down when the landscape moved. There is not much fact about how the landscapes locked, like if there were any trees.

The only """real""" fact that you can find about the geographic landscape is that there were rocks. Scienctists may have found out that during this era, there was a mountian higher than mount everest, approximetly 9km long.

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geographic landscape Mesoproterozoic - Google Search