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[15] [16] The Moon's gravitational pull stabilised Earth's fluctuating axis of rotation, setting up regular climatic conditions favoring abiogenesis. [17] 4404 Ma Evidence of the first liquid water on Earth which were found in the oldest known zircon crystals. [18] 4280–3770 Ma Earliest possible appearance of life on Earth. [19] [20] [21] [22]
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 ...
Feliform evolutionary timeline. All modern carnivorans, including cats, evolved from miacoids, which existed from approximately 66 to 33 million years ago.There were other earlier cat-like species but Proailurus (meaning "before the cat"; also called "Leman's Dawn Cat"), which appeared about 30 million years ago, is generally considered the first "true cat".
It lacked wrists, and was generally poorly adapted for life on land. The limbs could not support the animal's weight. Acanthostega had both lungs and gills, also indicating it was a link between lobe-finned fish and terrestrial vertebrates. The dorsal pair of ribs form a rib cage to support the lungs, while the ventral pair disappears.
The age of Earth is about 4.54 billion years; [7] [33] [34] the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago according to the stromatolite record. [35] Some computer models suggest life began as early as 4.5 billion years ago. [36] [37] The oldest evidence of life is indirect in the form of isotopic ...
Very precocial birds can be ready to leave the nest in a short period of time following hatching (e.g. 24 hours). Many precocial chicks are not independent in thermoregulation (the ability to regulate their body temperatures), and they depend on the attending parent(s) to brood them with body heat for a short time. Precocial birds find their ...
Kittens are able to chew solid food around 5–6 weeks after birth, and it is recommended that 30% of their diet should consist of solid food at this time. [32] The kitten remains on the mother's milk until around eight weeks of age when weaning is complete and a diet of solid food is the primary food source.
Time interval, before the present time. a=annus (year) Period Event, invention or historical development 13.8 Ga – 11 Ga: Big Bang occurs when ordinary space and time develop from a primeval state (possibly a false vacuum) described by a quantum theory of gravity or "theory of everything". Infant universe cools as it begins expanding outward.