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53

The answer to your question is yes it is certainly possible. At one time it was thought that there was something special about "organic" chemicals which meant that they could not be artificially synthesised out of fundamental elements. In 1828 Frederick Wöhler synthesised urea (CO(NH2)2) which is often taken as the first demonstration that the organic v ...


49

Why do we age is a classical question in Evolutionary Biology. There are several things to consider when we think of how genes that cause disease, aging, and death to evolve. One explanation for the evolution of aging is the mutation accumulation (MA) hypothesis. This hypothesis by P. Medawar states that mutations causing late life deleterious (damaging) ...


36

Living organisms can be divided into hetrotrophs and autotrophs. Autotrophs like plants and algae are able to produce complex organic compounds from relatively simple inorganic components. They are satisfied with sunlight, water and other abiotic stuff and do not need to consume "life". We -- along with all other animals -- are not autotrophs, but ...


36

SolarLunix posted an excellent answer detailing the criteria for being classified as "alive", and showed that by those criteria, mitochondria could be considered as "dead". However, I would argue that the narrator's statement in your video does not make any sense. The currently-accepted theory of the evolution of mitochondria (and possibly other organelles) ...


21

Even on a purely synthetic diet, your body would still use living cells as an energy source. Our bodies contain more bacterial cells than human, mostly contained in our gut. These microbes process any nutrients we ingest and when they die, we absorb their cellular components as nutrition. The lining of the gut is the most rapidly dividing population of ...


17

This is a very good question. There is a big ongoing field of research called "evolution of aging/senescence" that tackles this question. I won't give you a complete overview of the different hypothesis the could explain why we age but here is a fundamental concept that is to know. We'll assume that there is some extrinsic mortality, mortality against ...


17

Generally frogs are cold blooded animals (more specifically ectothermic or poikilothermic) . Wood frogs can maintain their body temperature by production of cryoprotectants which a human body cannot produce from normal metabolic processes. Such molecules depress the freezing point of tissue and avoid ice formation. Here is a scientific report on the ...


14

Your question is phrased somewhat ambiguously as to whether you're asking about the theoretical possibility, the feasibility, or the practical ability in everyday life. 1) Theoretically, yes. It is chemically possible to produce all substances that humans need to survive without the use of living organisms in the process. In the end, biological systems use ...


14

Short answer: According to the definition of life, yes, Mitochondria are "dead". To be considered alive an organism must meet the following criteria: organized structure performing a specific function an ability to sustain existence, e.g. by nourishment an ability to respond to stimuli or to its environment capable of adapting an ...


12

How can really even draw a defined line of what life is? It's easy, really: just make one. In the answer I linked to I go into the reasons why viruses aren't alive (spoiler alert: no ribosomes) and what our current definition is, but the bigger question is why does it matter? We can draw the line wherever we want to, but it's still an arbitrary construct ...


12

The definition of life is the main issue here. That is one of the great philosophical questions in Biology (and not only Biology) and is way beyond the simple Q&A format of this site. However, most definitions of life can be boiled down to1: A self replicating entity that interacts2 with its environment. Or, even more simply [1]: Life is self-...


12

I would like to expand a bit on SolarLunix's post, because the logic used in the conclusion would also mean that endosymbionts, such as https://en.wikipedia.org/wiki/Buchnera_(bacterium), who cannot survive outside their host are also "dead". I think many of us disagree with that notion, so instead I would say that it's the fact that so many of their genes ...


10

Actually, genetically, there is no reason for animals to continue to exist after they have procreated. If you look at salmon, they die immediately after procreating, which is probably the most efficient way to carry the best genes to the next generation. In the case of mammals, they need to teach their offspring where to find food, where to find water and ...


10

Because evolution isn't about individuals: it's about species. What matters to natural selection isn't how long you live, but how many grandchildren you have. A long lifespan can be an evolutionary advantage, but like any trait, it's only an advantage to the extent that allows you to reproduce more. It would seem that a longer lifespan would be advantageous ...


9

It may never have happened again, however, since all lifeforms on Earth today are similar on a molecular level (DNA), suggesting a common origin. An important distinction to make here is that all extant life on Earth has a common origin. It's completely possible that abiogenesis occurred many times, but whatever organisms emerged as a result became ...


9

The definition of life is a controversy in itself, and as it is simply a word that can be understood by everyone however they wish, there is no "correct" definition. It is thus not really possible to give a "correct" answer to your question, but here are a list of things you may want to consider: Replication of DNA is probably the most agreed common ...


9

Depends on how you define "life"? Is unfertilized chicken eggs alive? What about cow milk? Well there are bacteria in it. What if you get rid of that bacteria? Then some people would not be able to utilize lactose... Also as Bez mentioned rice grains are quiescent, meaning they are in a dormant state and not really "alive" but again depends on how you ...


8

OK, so we know a couple of things about life in the universe. Note, however, that this is not really an answer and is also not very biological in nature. So, we don't know how life began on the Earth. However, do know that: The probability of life evolving on a planet in the universe is non-zero (since we exist) and, So far, we have not found evidence ...


7

Depends on what kind of life you want! The Database of Essential Genes lists genes essential for life for a number of species, although I would be wary of some of the numbers; bacterial results are probably more reliable but it lists 118 for humans and 2114 for mice. There are a bunch of different numbers for different E. coli strains, with larger numbers ...


7

Yes. The Bristlecone Pine, Pinus longaeva, is one example. This species boasts the oldest individual living organisms, and also has been convincingly argued by Lanner and Connor (2001) to show no evidence of senescence. While the Wikipedia page on Biological Immortality (as of June 2013) unfortunately ignores plants, the pages on Negligible Senescence and ...


7

Question: Is it possible for humans to live healthy long lives without eating any type of life, i.e no animals, no plants? First, according to a definition of a living organism(biology-online), milk is not live, because it does not have an ability to reproduce itself, among other... My claim: If you consider milk and honey non-live (no DNA), then, yes, ...


6

I now found this Wikipedia article on biological immortality. It's pretty much what I was looking for. Wikipedia describes the phenomenon as follows: Biological immortality refers to a stable or decreasing rate of mortality from cellular senescence as a function of chronological age. Various unicellular and multicellular species may achieve this ...


6

No. It is possible but extraordinarily impractical to nourish yourself without killing animals, plants or even bacteria, as many have explained in detail. However, your immune system constantly kills pathogens that infect your body. What's worse, the macrophages literally catch and eat these bacteria alive, so you are very much "consuming" them. You could ...


5

In men, gout is associated with a higher risk of death from all causes. This would imply that their life expectancy is shorter. From a review by Kim et al. (1): Among men who did not have pre-existing coronary heart disease, the increased mortality risk is due primarily to an elevated risk of cardiovascular death, particularly from coronary heart ...


5

The issue I suspect you are struggling with is the anthropomorphization of the evolutionary process. Evolution is an optimization process driven by random mechanisms...i.e. there is often not a "reason" for why certain things are the way they are. Evolution is not a conscious "designer" that produces things with a specific goal in mind...it simply "picks" ...


5

All of your reasoning is correct - viruses are not motile (i.e. not self-propelled). I don't understand why you think this would cause a difficulty in the case of bacteria. Edit in response to comment @Remi.b Some cursory research on estimating probabilities of collisions between particles engaged in random walks has revealed some very challenging maths. ...


5

First, the "snowball earth", despite favoured by many scientists, is not a theory in the scientific meaning of the term, but a hypothesis, because it is not widely accepted: https://en.wikipedia.org/wiki/Snowball_Earth#Scientific_dispute. Some models show sea ice at the equator, while some more sophisticated climatic models failed to form sea ice to the ...


4

...many biologist/scientists say that viruses are not living because everything they do is just chemicals carrying out their predefined chemistry. I don't think that's correct. Many definitions of life exclude viruses because they lack the apparatus to perform the life functions themselves, especially reproduction. They don't seem to qualify as parasites ...


4

It may never have happened again, however, since all lifeforms on Earth today are similar on a molecular level Actually, the similarity is at the chemical level where the chirality of all known-life's amino acids are "left-handed" (see http://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Alternative-chirality_biomolecules). Since there is no ...


4

News to me is that about 4500 of the 4900 minerals on Earth have been created by life. After reading the article, this isn't what was said. What was said is that life increases mineral diversity on a planet, most notably through biproducts reacting with existing minerals (like Oxygen - a biproduct of photosynthesis - reacting with iron to create iron-...



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