Formation. When the solar system settled into its current layout about 4.5 billion years ago, Earth formed when gravity pulled swirling gas and dust in to become the third planet from the Sun.
October 23, 4004 B.C.: Happy Birthday Earth! - Scientific American Blog Network.
The first human ancestors appeared between five million and seven million years ago, probably when some apelike creatures in Africa began to walk habitually on two legs. They were flaking crude stone tools by 2.5 million years ago. Then some of them spread from Africa into Asia and Europe after two million years ago.
Human evolution is the lengthy process of change by which people originated from apelike ancestors. Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.
Co-lead researcher Shimona Kealy said these people probably travelled through Indonesia's northern islands, into New Guinea and then Australia, which were part of a single continent between 50,000 and 70,000 years ago, when sea levels were 25-50 metres below the current level.
Homo sapiens, the first modern humans, evolved from their early hominid predecessors between 200,000 and 300,000 years ago. They developed a capacity for language about 50,000 years ago. The first modern humans began moving outside of Africa starting about 70,000-100,000 years ago.
Modern humans originated in Africa within the past 200,000 years and evolved from their most likely recent common ancestor, Homo erectus, which means 'upright man' in Latin. Homo erectus is an extinct species of human that lived between 1.9 million and 135,000 years ago.
From about 1.2 million years ago to less than 100,000 years ago, archaic humans, including archaic Homo sapiens, were dark-skinned.
No! After the dinosaurs died out, nearly 65 million years passed before people appeared on Earth. However, small mammals (including shrew-sized primates) were alive at the time of the dinosaurs.
By using not only the rocks on Earth but also information gathered about the system that surrounds it, scientists have been able to place Earth's age at approximately 4.54 billion years.
There are later descriptions of creatures in the Bible that could be referring to dinosaurs. One example is the behemoth of Job 40:15-19. Even in fairly modern history there are reports of creatures which seem to fit the description of dinosaurs.
Variables such as temperature, food sources, and oxygen levels are all factors that might impact dinosaur survival. Because dinosaurs lived in much warmer climates millions of years ago, many experts doubt they could even survive today.
For approximately 120 million years—from the Carboniferous to the middle Triassic periods—terrestrial life was dominated by the pelycosaurs, archosaurs, and therapsids (the so-called "mammal-like reptiles") that preceded the dinosaurs.
Basic math tells us that all humans share ancestors, but it's amazing how recently those shared ancestors lived. Thanks to genetic data in the 21st century, scientists are discovering that we really are all descended from one mother.
A new genomic study has revealed that Aboriginal Australians are the oldest known civilization on Earth, with ancestries stretching back roughly 75,000 years.
A new genetic study suggests all modern humans trace our ancestry to a single spot in southern Africa 200,000 years ago.
Humans looked essentially the same as they do today 10,000 years ago, with minor differences in height and build due to differences in diet and lifestyle.
But even without such dramatic doomsday scenarios, astronomical forces will eventually render the planet uninhabitable. Somewhere between 1.75 billion and 3.25 billion years from now, Earth will travel out of the solar system's habitable zone and into the "hot zone," new research indicates.
No demographic data exist for more than 99% of the span of human existence. Still, with some assumptions about population size throughout human history, we can get a rough idea of this number: About 117 billion members of our species have ever been born on Earth.
They used these variations to create a more reliable molecular clock and found that Adam lived between 120,000 and 156,000 years ago. A comparable analysis of the same men's mtDNA sequences suggested that Eve lived between 99,000 and 148,000 years ago1.
Adam is the name given in Genesis 1-5 to the first human. Beyond its use as the name of the first man, adam is also used in the Bible as a pronoun, individually as "a human" and in a collective sense as "mankind".
Adam and Eve, according to the creation myth of the Abrahamic religions, were the first man and woman. They are central to the belief that humanity is in essence a single family, with everyone descended from a single pair of original ancestors.
Mammals: After the extinction, mammals came to dominate the land. An early relative of all primates, including humans, survived the extinction. Snakes: Although a number of snake species died out around 65 million years ago, snakes as a group survived.
We now have a better idea of what T. rex's ancestors may have been like. Two fossils have been found of a new tyrannosaur species, dubbed Suskityrannus hazelae, that lived around 90 million years ago, before the tyrannosaurs evolved into giants like T. rex.
The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old. The signals consisted of a type of carbon molecule that is produced by living things.