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  2. Precambrian - Wikipedia

    en.wikipedia.org/wiki/Precambrian

    The Precambrian is an informal unit of geologic time, [3] subdivided into three eons (Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga ) to the beginning of the Cambrian Period, about 538.8 million years ago ( Ma ), when hard-shelled creatures first appeared in ...

  3. Common descent - Wikipedia

    en.wikipedia.org/wiki/Common_descent

    Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. According to modern evolutionary biology, all living beings could be descendants of a unique ancestor commonly referred to as the last universal common ancestor (LUCA) of all life on Earth.

  4. Timeline of human evolution - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_human_evolution

    Date Event 4.3-4.1 Ga The earliest life appears, possibly as protocells.Their genetic material was probably composed of RNA, capable of both self replication and enzymatic activity; their membranes were composed of lipids.

  5. History of life - Wikipedia

    en.wikipedia.org/wiki/History_of_life

    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 ...

  6. Last universal common ancestor - Wikipedia

    en.wikipedia.org/wiki/Last_universal_common_ancestor

    His formal test favoured the existence of a universal common ancestry over a wide class of alternative hypotheses that included horizontal gene transfer. Basic biochemical principles imply that all organisms do have a common ancestry. [71] A proposed, earlier, non-cellular ancestor to LUCA is the First universal common ancestor (FUCA).

  7. Evolution of mammals - Wikipedia

    en.wikipedia.org/wiki/Evolution_of_mammals

    Figure 1:In mammals, the quadrate and articular bones are small and part of the middle ear; the lower jaw consists only of dentary bone.. While living mammal species can be identified by the presence of milk-producing mammary glands in the females, other features are required when classifying fossils, because mammary glands and other soft-tissue features are not visible in fossils.

  8. Earliest known life forms - Wikipedia

    en.wikipedia.org/wiki/Earliest_known_life_forms

    Evidence of possibly the oldest forms of life on Earth has been found in hydrothermal vent precipitates. [1]The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia. [2]

  9. Descent from antiquity - Wikipedia

    en.wikipedia.org/wiki/Descent_from_antiquity

    In European genealogy, a descent from antiquity (DFA or DfA) is a proven unbroken line of descent between specific individuals from ancient history and people living today. . Ancestry can readily be traced back to the Early Middle Ages, but beyond that, insufficient documentation of the ancestry of the new royal and noble families of the period makes tracing them to historical figures from ...

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