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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 ...
In relation to biological organisms. Zygote, at the start of an organism's life. Embryo, early in an organism's life. Foetus, early in an animal's life, occurring before birth. Larva, an early stage in many animal life forms before maturity. Child, early human life.
Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from matter that does not. It is defined descriptively by the capacity for homeostasis, organisation, metabolism, growth, adaptation, response to stimuli, and reproduction. All life over time eventually reaches a state of ...
The timeline of the evolutionary history of life represents the current scientific theory outlining the major events during the development of life on planet Earth. Dates in this article are consensus estimates based on scientific evidence, mainly fossils. In biology, evolution is any change across successive generations in the heritable ...
Early childhood development. Early childhood development is the period of rapid physical, psychological and social growth and change that begins before birth and extends into early childhood. [1] While early childhood is not well defined, one source asserts that the early years begin in utero and last until 3 years of age. [1]
History of childhood. The history of childhood has been a topic of interest in social history since the highly influential book Centuries of Childhood, published by French historian Philippe Ariès in 1960. He argued "childhood" as a concept was created by modern society. Ariès studied paintings, gravestones, furniture, and school records.
Poor nutrition early in life contributes to stunting, and by the age of two or three can be associated with cognitive deficits, poor school achievement, and, later in life, poor social relationships. [184] Malnutrition is a large problem in developing nations, and has an important effect on young children's weight and height. Children suffering ...
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] The earliest evidence of life found in a stratigraphic unit, not just a single mineral grain, is the 3.7 Ga metasedimentary rocks containing ...