Discover the history and the mysteries of the Earth
The Megalodon, or Meg, was a giant prehistoric shark that was the fiercest predator to have ever lived on the Earth
Growing up to 60 feet long and weighing over 50 tons, the Meg was one of the largest creatures to ever roam the ocean. During the Miocene and Pliocene epochs, the Megalodon was the devil of the seas, preying on a variety of other marine creatures including whales, dolphins, and seals. The giant prehistoric shark Megalodon went extinct over 3.6 million years ago.
How old is the Earth?
The Earth is estimated to be around 4.5 billion years old. When the planet was newly formed it was uninhabitable. According to scientists, the Earth’s surface was almost entirely covered up by molten lava. It also had no atmosphere at the time.
Eventually, the planet began to cool over the course of a few hundred million years, and thus began the emergence of oceans consisting of liquid water.
Holocene Extinction
Unlike the mass extinctions of the past, scientists predict one of the future to be human-induced. During the last several centuries humans have burned immense amounts of fossil fuels, used more than half of the planet’s unfrozen land for cities, and have hunted animals such as the woolly mammoth and giant kangaroo to extinction. In the 200,000 years on the planet, some scientists estimate humans have caused the extinction of 1,000 species. Currently, around 1 million animal and plant species are now threatened with extinction.
Considering this, some scientists argue, the sixth extinction event is in effect, called the Holocene. However, not all scientists agree and some say the extinction event has not happened quite yet. Whether the sixth extinction event is upon the world or not, the Holocene is unlike extinction events of the past in that it is human-induced. People can choose to change how they interact with the environment. Keeping this in mind, there is still hope for the future.
Cretaceous–Paleogene Extinction
65 million years ago
Of the five mass extinction events, the Cretaceous-Paleogene is probably the most well-known. This is the mass extinction event that saw the extinction of the non-avian dinosaurs around 65 million years ago. Many vertebrates were also lost, including the flying pterosaurs. In the oceans, marine invertebrates disappeared, including ammonites.
The extinction enabled mammals to evolve on land and sharks to further evolve in the oceans. The Paleogene was a significant period, seeing the evolution of species such as bats and whales. Most scientists agree that an asteroid caused this mass extinction event. Geological evidence indicates the asteroid would have had a diameter of six miles. There is a debate if the asteroid was the sole cause of the extinction event or if other factors contributed to the extinction.
Triassic–Jurassic Extinction
199 million to 214 million years ago
After the Great Dying, life took a long time to recover and flourish. However, once life started to diversify another extinction event took place. During the Triassic-Jurassic extinction event, 76% of all marine and terrestrial species perished.
At the beginning of the period, mammals outnumbered dinosaurs but by the end, dinosaurs outnumbered mammals. This extinction event enabled the dinosaurs to temporarily be earth’s dominant species.
Scientists disagree about the cause of the Triassic-Jurassic extinction event. Some scientists theorize climate change and rising sea levels resulting from the sudden release of large amounts of carbon dioxide caused the extinction event.
Permian–Triassic Extinction
Arguably earth's worst extinction event, the Permian-Triassic extinction event saw approximately 90% of earth's species disappear. This included the disappearance of over 96% of marine species and 70% of terrestrial species. The Permian-Triassic extinction event is the only mass extinction event that took a toll on the insect population, wiping them out in large numbers.
Since so many species perished, the Permian-Triassic extinction event is also called, "The Great Dying". The Great Dying started with a volcanic explosion from the Siberian Traps, an immense volcanic complex. The eruption released more than 720,000 cubic miles of lava across what is now known as Siberia, triggering the release of immense amounts of carbon dioxide.
This resulted in global warming. The release of carbon also fed different kinds of bacteria that emitted large amounts of methane. Many geologists and paleontologists agree the extinction event took place over the course of 15 million years. However, some argue the extinction event took place over the span of only 200,000 years.
80 Shackled Skeletons Found in Greek Grave After Ancient Mᴀss Ex*****on
Archeologists offered the first image of the site where 80 skeletons in an mᴀss grave with wrists clamped by iron shackles lie in an ancient Greek cemetery
The skeletal remains show the bodies were placed in a row upon death.
The archaeologist's team said that the fossils, which could date from 632 BC, were the result of an mᴀss ex*****on.
More than 1,500 bodies are buried in the ancient Falyron Delta cemetery in Athens.
The cemetery dates from between the 8th and 5th century BC.
“It is a period of great unrest for Athenian society, a period where aristocrats, nobles, are battling with each other for power,” Dr. Chryssoulaki said.
One of the strongest theories is that they were supporters of Cylon, an Athenian noble and Olympic champion who staged an attempted coup in Athens in 632 BC with the help of his father-in-law, the tyrant of Megara.
Experts say the people who were killed were supporting a failed ancient coup.
The coup failed and Cylon hid in a temple of the Acropolis. He managed to escape, but the people who backed him were killed.
“Perhaps with the DNA tests that we will do on these skeletons we may confirm or not this hypothesis that these deceased, these young people could be … part of a coup … an attempt by a noble to take power by force,” Dr. Chryssoulaki said.
More than 1,500 bodies lie in the whole cemetery; some infants are laid to rest in ceramic pots, and other adults are burned on funeral pyres or buried in stone coffins.
Unlike Athens’ renowned ancient Kerameikos cemetery, the last resting place of many prominent ancient Greeks, these appear to be the inhabitants of regular neighborhoods.
Late Devonian Extinction
Starting 383 million years ago, earth's second mass extinction called the late Devonian extinction occurred. During the Devonian period, organisms that survived the late Ordovician extinction were steadily recovering.
In the Devonian extinction, around 70 to 80% of marine life disappeared. Open water swimmers such as sharks and bony fish survived the extinction, while nearly all the bottom fish disappeared. More shallow water and reef-dwelling fish died in the Devonian extinction because they are more sensitive to changes in ocean chemistry than animals living in deeper water.
Scientists are not yet sure if the extinction happened in one larger event or several pulses spanning millions of years. A combination of low-temperature stress (hypothermia) and oxygen deprivation (hypoxia) caused the mass extinction event. Some scientists theorize a meteorite or volcanic eruption was a possible trigger.
890-million-year-old sponge fossil may be the earliest animal yet found
Ordovician–Silurian Extinction
The Ordovician-Silurian period saw earth's first mass extinction 443 million years ago. Approximately 85% of the earth’s species disappeared. Scientists believe climate change caused mass extinction. Climates cooled globally after an ice age in the southern hemisphere. The extinction happened in two waves, one million years apart, which resulted in glaciation and falling sea levels.
The first wave of extinction happened 443 million years ago when climates cooled down. The second wave happened about a million years later when the ice age was coming to an end and the climate was warming. Animals had not yet ventured to land at the time, so the extinction impacted marine life. While all the major animal groups survived, each lost important members, and graptolites came close to total extinction.
Do you know ? The earliest epoch of earth's geological history
Precambrian
The Precambrian Time Span is the earliest time period on the Geologic Time Scale. It stretches from the formation of the earth 4.6 billion years ago to around 600 million years ago and encompasses many Eons and Eras leading up to the Cambrian Period in the current Eon.
The earliest known fossils are from the Archean Eon epoch of this epoch, which began at 4,000 mya, or 4 billion years ago. Overall, the Precambrian Era accounts for 88% of Earth's history
Beginning of Earth
The earth was formed about 4.6 billion years ago in a violent explosion of energy and dust according to the rock record from Earth and other planets. For about a billion years, the earth was a barren place of volcanic action and a less than suitable atmosphere for most types of life. It wasn't until about 3.5 billion years ago that it is thought that the first signs of life formed.
Early Earth: A Battered, Hellish World with Water Oases for Life
An artistic conception of the early Earth-moon system showed the Earth's surface after being bombarded with large impacts, causing magma extrusion on the surface, though some liquid water was retained.
Asteroids and comets that repeatedly smashed into the early Earth covered the planet's surface with a molten rock during its earliest days, but still may have left oases of water that could have supported the evolution of life, scientists say.
The new study reveals that during the planet's infancy, the surface of the Earth was a hellish environment, but perhaps not as hellish as often thought, scientists added.
Earth formed about 4.5 billion years ago. The first 500 million years of its life are known as the Hadean Eon. Although this time amounts to more than 10 percent of Earth's history, little is known about it, since few rocks are known that are older than 3.8 billion years old
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