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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 ...
There are numerous plants and animals for which the mortality rate has been observed to actually decrease with age, for all or part of the life cycle. [2] Hydra were observed for four years without any increase in mortality rate. [3] If the mortality rate remains constant, the rate determines the mean lifespan.
The most well known examples are antibiotic resistance in the medical field along with better-known laboratory experiments documenting evolution's occurrence. Natural selection is tantamount to common descent in that long-term occurrence and selection pressures can lead to the diversity of life on earth as found today.
A life form (also spelled life-form or lifeform) is an entity that is living, [1] [2] such as plants , animals , and fungi . It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species, [3] are extinct. [4] [5] Earth is the only celestial body known to harbor life forms. No form of ...
The origin of life has not been established by science, however, some evidence suggests that life may already have been well-established only a few hundred million years after the formation of the Earth. Until approximately 2.5 billion years ago, all life consisted of microorganisms – archaea, bacteria, and single-celled protozoans and ...
Land plants evolved from a group of freshwater green algae, perhaps as early as 850 mya, [3] but algae-like plants might have evolved as early as 1 billion years ago. [2] The closest living relatives of land plants are the charophytes, specifically Charales; if modern Charales are similar to the distant ancestors they share with land plants, this means that the land plants evolved from a ...
The Encyclopedia of Life (EOL) is a free, online encyclopedia intended to document all of the 1.9 million living species known to science. It aggregates content to form "pages" for every known species. Content is compiled from existing trusted databases which are curated by experts and it calls on the assistance of non-experts throughout the world.