How is life scientifically defined?

Question

How does the scientific community define life or something as being alive?

Answer 1

In school I was taught MRS GREN as a way to remember the characteristics of living things-

Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition

Not all species are covered by this but its a good introductory checklist.

Answer 2

Viruses aren't considered alive by many since they can't reproduce without a host; however, some bacteria can't either. So, for the sake of consistency, I say viruses are alive. They're nothing more than self-replicating molecules.

Not all life even needs RNA or DNA, some organisms are just proteins! So life is really just molecules that reproduce themselves. Some have membranes to separate their internal processes from the environment.

Answer 3

Predominately considered to be a characteristic of humans, plants and animals. However, even inert matter is in constant movement and change. We continue to find life in places that we did not believe that it could exist, such as on the bottom of the sea floor around thermal vents. Perhaps our ideas of what is living and what is non-living are flawed and merely the measure of our ignorance and restricted powers of observation. Many consider that the earth is alive.

Answer 4

Tears are a liquid produced by potential of the physique's technique of lacrimation to bathe and lubricate the eyes. The be conscious lacrimation is often utilized in a scientific or literary sense to consult with crying. One lacrimal gland is placed above and beside each and every eye, at the back of the better eyelid. The lacrimal glands secrete lacrimal fluid which flows by lacrimal ducts into the gap between the eyeball and lids. whilst the eyes blink the lacrimal fluid is unfold around the exterior of the attention. The lacrimal fluid flows interior the path of the lacrimal lake by potential of the puncta to the lacrimal caniliculi on the indoors nook of the eyelids then interior the path of the nasolacrimal duct, and ultimately into the nasal hollow area. An far extra advantageous than tears, as with solid emotion, can for this reason reason the nostril to run. There are 3 situation-loose forms of tears: a million.) Basal tears: In wholesome mammalian eyes, the cornea is constantly stored moist and nourished by potential of basal tears. They lubricate the attention and help to maintain it clean of dirt. Tear fluid incorporates water, mucin, lipids, lysozyme, lactoferrin, lipocalin, immunoglobulins, glucose, urea, sodium, and potassium. a number of the components in lacrimal fluid combat against bacterial an infection as a element of the immune equipment. 2.) Reflex tears: the 2nd style of tears outcomes from inflammation to the attention by potential of foreign places debris, or components consisting of onion vapors or tear gasoline or pepper spray. those reflex tears attempt to bathe out irritants that could are starting to be into the attention. 3.) Crying or weeping: The third class, additionally observed as crying or weeping, is extra advantageous lacrimation as a results of solid emotional stress or soreness. this custom isn't constrained to adverse thoughts; lots of human beings have been ordinary to cry whilst relatively chuffed. In human beings, emotional tears could nicely be observed by potential of reddening of the face and sobbing — cough-like, convulsive respiratory, now and lower back regarding spasms of the full bigger physique. Tears introduced approximately by potential of thoughts have a distinct chemical make up than those for lubrication.

Answer 5

an organismic state characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction

but everybody has his or her own interpretation of what life is and the meaning behind it. humanity has debated the question of "what is life?" for several millenia, and i believe we will continue to argue for many more