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The definition of life has long been a challenge for scientists and philosophers. [2] [3] [4] This is partially because life is a process, not a substance. [5] [6] [7] This is complicated by a lack of knowledge of the characteristics of living entities, if any, that may have developed outside Earth.
The underlying theme of the essay is the need to teach biological evolution in the context of debate about creation and evolution in public education in the United States. [5] The fact that evolution occurs explains the interrelatedness of the various facts of biology, and so makes biology make sense. [6]
Professor of biology Jerry Coyne sums up biological evolution succinctly: [3]. Life on Earth evolved gradually beginning with one primitive species – perhaps a self-replicating molecule – that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.
While the human life span has increased markedly since the 19th century, new research shows that despite recent advancements in medicine, we may have reached our longevity peak—and most of today ...
The researchers discovered that while humans have gained about 30 years of life expectancy over the 20 th century, improvements in overall life expectancy have slowed—and actually declined in ...
“S. cerevisiae holds great potential in libraries of new chromosomes,” the researchers said in the same study, “[including] neochromosomes, and genomes for subsequent transfer into cells to ...
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 ...
Starting in 1985, researchers proposed that life arose at hydrothermal vents, [235] [236] that spontaneous chemistry in the Earth's crust driven by rock–water interactions at disequilibrium thermodynamically underpinned life's origin [237] [238] and that the founding lineages of the archaea and bacteria were H 2-dependent autotrophs that used ...