Question

What information do scientists still lack concerning the history of life on earth?

Answer 1

The evolutionary history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to the present. Earth formed about 4.5 billion years (Ga) ago and evidence suggests life emerged prior to 3.7 Ga](Although there is some evidence of life as early as 4.1 to 4.28 Ga, it remains controversial due to the possible non-biological fomation of the purported fossils. The similarities among all known present-day species indicate that they have diverged through the process of evolution from a common ancestor.[8]Approximately 1 trillion species currently live on Earth of which only 1.75–1.8 million have been named  and 1.6 million documented in a central database.  These currently living species represent less than one percent of all species that have ever lived on earth.

Life timeline

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water

Single-celled life

photosynthesis

Eukaryotes

Multicellular life

Arthropods and Molluscs

Plants

Dinosaurs

Mammals

Flowers

Birds

Primates

 

 

 

 

 

 

 

 

 

 

 

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Earth (−4540)

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Earliest water

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Earliest life

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Earliest oxygen

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Atmospheric oxygen

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Oxygen crisis

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Sexual reproduction

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Earliest plants

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Ediacaran biota

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Cambrian explosion

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Tetrapoda

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Earliest apes

Phanerozoic

Proterozoic

Archean

Hadean

Pongola

Huronian

Cryogenian

Andean

Paleozoic

Quaternary

Ice Ages

Axis scale: million years

Also see: Human timeline and Nature timeline



The earliest evidence of life comes from biogenic carbon signatures[2][3] and stromatolite fossils[15] discovered in 3.7 billion-year-old metasedimentary rocks from western Greenland. In 2015, possible "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia  In March 2017, putative evidence of possibly the oldest forms of life on Earth was reported in the form of fossilized microorganisms discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada, that may have lived as early as 4.28 billion years ago, not long after the oceans formed 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.