Search results
Results from the WOW.Com Content Network
Life history theory has provided new perspectives in understanding many aspects of human reproductive behavior, such as the relationship between poverty and fertility. [43] A number of statistical predictions have been confirmed by social data [ citation needed ] and there is a large body of scientific literature from studies in experimental ...
Neutering, from the Latin neuter ('of neither sex'), [1] is the removal of a non-human animal's reproductive organ, either all of it or a considerably large part. The male-specific term is castration, while spaying is usually reserved for female animals. Colloquially, both terms are often referred to as fixing. [2]
Surgical castration in animals is often called neutering. Castration of animals is intended to favor a desired development of the animal or of its habits, as an anaphrodisiac or to prevent overpopulation. The parallel of castration for female animals is spaying. Castration may also refer medically to oophorectomy in female humans and animals.
If true, this would challenges the common belief [3] [4] in existence of a fixed maximal human life span. Biodemographic studies have found that even genetically identical laboratory animals kept in constant environment have very different lengths of life, suggesting a crucial role of chance and early-life developmental noise in longevity ...
The theory that DNA damage is the primary cause of aging is based, in part, on evidence in human and mouse that inherited deficiencies in DNA repair genes often cause accelerated aging. [ 29 ] [ 30 ] [ 27 ] There is also substantial evidence that DNA damage accumulates with age in mammalian tissues, such as those of the brain, muscle, liver and ...
By another definition, however, maximum life span corresponds to the age at which the oldest known member of a species or experimental group has died. Calculation of the maximum life span in the latter sense depends upon the initial sample size. [1] Maximum life span contrasts with mean life span (average life span, life expectancy), and longevity.
However, viruses are still poorly understood and may have arisen before "life" itself, or may be a more recent phenomenon. Major extinctions in terrestrial vertebrates and large amphibians. Earliest examples of armoured dinosaurs. 195 Ma First pterosaurs with specialized feeding (Dorygnathus). First sauropod dinosaurs.
Biological immortality (sometimes referred to as bio-indefinite mortality) is a state in which the rate of mortality from senescence (or aging) is stable or decreasing, thus decoupling it from chronological age.