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Evolution of live birth , with early therians probably having pouches for keeping their undeveloped young like in modern marsupials. Nipples stemmed out of the therian milk lines. The posterior orifice separates into anal and urogenital openings; males possess an external penis.
The Earth was formed at 4.54 Gya, and the earliest evidence of life on Earth dates from at least 3.8 Gya from Western Australia. Some studies have suggested that fossil micro-organisms may have lived within hydrothermal vent precipitates dated 3.77 to 4.28 Gya from Quebec , soon after ocean formation 4.4 Gya during the Hadean .
The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; [30] graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; [31] and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
If an earlier civilization existed on Earth millions of years ago, we might have trouble finding evidence of it -- but that doesn't mean it didn't exist.
Human history is the record of humankind from prehistory to the present. Modern humans evolved in Africa around 300,000 years ago and initially lived as hunter-gatherers.They migrated out of Africa during the Last Ice Age and had spread across Earth's continental land except Antarctica by the end of the Ice Age 12,000 years ago.
The hominoids are descendants of a common ancestor.. Human evolution is the evolutionary process within the history of primates that led to the emergence of Homo sapiens as a distinct species of the hominid family that includes all the great apes. [1]
This is an accepted version of this page This is the latest accepted revision, reviewed on 25 December 2024. Scientific projections regarding the far future Several terms redirect here. For other uses, see List of numbers and List of years. Artist's concept of the Earth 5–7.5 billion years from now, when the Sun has become a red giant While the future cannot be predicted with certainty ...