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A life history strategy is the "age- and stage-specific patterns" [2] and timing of events that make up an organism's life, such as birth, weaning, maturation, death, etc. [3] These events, notably juvenile development, age of sexual maturity, first reproduction, number of offspring and level of parental investment, senescence and death, depend ...
In 2010, based on "the vast array of molecular sequences now available from all domains of life," [70] D. L. Theobald published a "formal test" of universal common ancestry (UCA). This deals with the common descent of all extant terrestrial organisms, each being a genealogical descendant of a single species from the distant past. His formal ...
Experimentalists used a variety of terms for the study of the origin of life from nonliving materials. Heterogenesis was applied to the generation of living things from once-living organic matter (such as boiled broths), and the English physiologist Henry Charlton Bastian proposed the term archebiosis for life originating from non-living materials.
The theory held that "lower" animals are generated by decaying organic substances. Aristotle stated that, for example, aphids arise from dew on plants, flies from putrid matter, mice from dirty hay, and crocodiles from rotting sunken logs. [16] The basic idea was that life was continuously created as a result of chance events. [17]
If an origin of life is hypothesised to involve a simple organism that had not yet evolved a membrane, let alone ATP, this would make the existence of reverse gyrase improbable. Moreover, phylogenetic studies show that reverse gyrase had an archaeal origin, and that it was transferred to bacteria by horizontal gene transfer.
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 biology, evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organization , from kingdoms to species , and individual organisms and molecules , such as DNA and proteins .
The tree of life or universal tree of life is a metaphor, conceptual model, and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin's On the Origin of Species (1859). [1]