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Schematic overview of the classes of stresses in plants Neurohormonal response to stress. Stress, whether physiological, biological or psychological, is an organism's response to a stressor such as an environmental condition. [1] When stressed by stimuli that alter an organism's environment, multiple systems respond across the body. [2]
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 ...
The theory of panspermia speculates that life on Earth may have come from biological matter carried by space dust [93] or meteorites. [94] While current geochemical evidence dates the origin of life to possibly as early as 4.1 Ga, and fossil evidence shows life at 3.5 Ga, some researchers speculate that life may have started nearly 4.5 billion ...
Stress proteins can exhibit widely varied functions within a cell- both during normal life processes and in response to stress. For example, studies in Drosophila have indicated that when DNA encoding certain stress proteins exhibit mutation defects, the resulting cells have impaired or lost abilities such as normal mitotic division and ...
Stress is highly individualized and depends on variables such as the novelty, rate, intensity, duration, or personal interpretation of the input, and genetic or experiential factors. Both acute and chronic stress can intensify morbidity from anxiety disorders. One person's fun may be another person's stressor.
4, which is a powerful greenhouse gas and was produced by early forms of life known as methanogens. Scientists continue to research how the Earth was warmed before life arose. [15] An atmosphere of N 2 and CO 2 with trace amounts of H 2 O, CH 4, carbon monoxide (CO), and hydrogen (H 2) is described as a weakly reducing atmosphere. [16]
A stressor is a chemical or biological agent, environmental condition, external stimulus or an event seen as causing stress to an organism. [1] Psychologically speaking, a stressor can be events or environments that individuals might consider demanding, challenging, and/or threatening individual safety.
Prolonged stress can disturb the immune, digestive, cardiovascular, sleep, and reproductive systems. [17] For example, it was found that: Chronic stress reduces resistance of infection and inflammation, and might even cause the immune system to attack itself. [27] Stress responses can cause atrophy of muscles and increases in blood pressure. [28]