37

There are both biological and social factor for that: Biological Females have two X chromosomes. When mutations in genes of the X chromosome occur, females have a second X to compensate. Males, on the other hand gave just one chromosome X and all genes its genes express themselves, even those lethal or deleterious. Females have better resistance to ...


14

Let's see! I took the most recent WHO data from here and did a quick an dirty analysis in R. Here is the histogram as well as a normal distribution with the same mean and standard deviation as the actual data: Does not look very normally distributed. In fact, the shapiro test confirms this impression: Shapiro-Wilk normality test data: df$life_expectancy ...


9

This is an interesting point you raise, and as the study you linked to states, "the link between physique and life expectancy is not clearly understood," which is certainly true at the moment. The relationship between BMI and lifespan in humans is a very different story to controlled dietary restriction in model organisms. Dietary restriction is defined as "...


8

Short answer: Changing something (instead of everything) yes. There are several studies on the impact of environmental factors on life span. Of course it depends from organism to organism. Diet restriction for example has been shown to extend life span of worms and mice. Temperature is also working well, at least with microorganisms, the metabolism of E....


6

There are a lot of factors playing in here. You've pointed out the surface reasons that can sometimes contribute: work accidents, style of life, etc. However, there are biological causes as you suspected. Probably the most obvious has to do with the difference between their hormones. Testosterone (male hormone) is associated with violence and risk taking. ...


6

The histogram you show isn't a distribution of age-at-death for individuals, it's a distribution of life expectancies for different countries. The post you link takes data from a table on the Wikipedia page List of countries by life expectancy. Interpreting the histogram you posted, we see average life expectancy seems to hit a wall around 85. This does ...


5

You will find here on the UN World Population Prospects plenty of data and visualization about change in life expectancy over time (among other things). The data also include predictions until year 2100. For example, here is the life expectancy data and predictions over time for men in Morocco. and here it is for women in Norway (note that x-axis range ...


5

We are only barely beginning to understand how the brain works, including memory. We do know that it is a very complex thing. There are many different kinds of memory; many different processes are involved in creating and recalling memories. One factor that plays into a naïve concept of "how old a memory is" is that "remembering" does not seem to be a ...


4

Are there known life expectancy differences in non human mammals by sex? Yes, there are. It is not well studied in general, but for certain species it is. Here is a relevant excerpt (Austad, Fischer, 2016): Females live longer than males in humans and all Old World monkeys and apes for which we have the best data. . . This appears to be true in both wild ...


4

A few people thought it would be interesting to see what the distribution looked like if we plotted the number of people dying at each age, so I took data from the SSA (which admittedly isn't global data, but it's probably fairly reflective of the world overall) and plotted the number of deaths per 100,000 at each age. This looks like it makes sense - the ...


3

There's no particular reason everything in nature needs to fit a normal distribution; normal distributions are just one of many different types of naturally-occurring distributions. In some cases, the other types can be transformed (e.g. by logarithms) into a normal distribution (e.g. a log-normal distribution), in other cases not so much. As to why it ...


3

I think you might be looking for period life tables A period life table is based on the mortality experience of a population during a relatively short period of time. Here we present the 2014 period life table for the Social Security area population. For this table, the period life expectancy at a given age is the average remaining number of years ...


3

On a basic level, the difference in lifespan is due to the fact that the nautilus has a vastly different reproduction strategy from other living cephalopods. While most other cephalopods exhibit a rather extreme form of r-Strategy reproduction, the nautilus is, relatively speaking, a K-Strategist. To explain, r-Strategy is when a species produces many ...


3

Extremely briefly, we do not evolve shorter lifespans because natural selection does not act for the good of the species. As an interesting historical aside, August Weismann proposed essentially the idea you are suggesting in 1889, in his Essays upon heredity and kindred biological problems. Within a few years, however, he backed away from this hypothesis.


3

How far could we go towards engineering a space-durable human species? I think this question is likely to get closed as off-topic. It is extremely hypothetical and would be a better fit on WorldBuilding.SE. But here is my messy attempt to answer this question. Assumptions So, I guess in your question, you assume that we know everything about how our ...


3

Since no source is given for the 30 - 40 years estimate in Wikipedia, we can't find out how the authors of the Wiki page reached that estimate, but 'someone made an educated guess' seems likely. There are a few reasonable ways that one might educatedly guess the longevity of the cama, but there are good reasons to treat those educated guesses with caution. ...


3

Lowest temperature 2, 3, 4 and 5 week beakers containing eggs and non-infective larvae in lamb faeces didn't develop into infective larvae (L3) when exposed to fluctuating temperatures ranging from -1 to 15°C: [...] there were no significant differences in the number of harvested larvae at the different time points for the faeces incubated at 15°C. However, ...


2

Probably not. There's a thing called Hayflick limit, which is basically a limit of life expectancy caused by a shortening of telomeres with every cell division. And since most of our cells complete cycles more based on time (life cycle of RBC 100 days), and not due to damages to a cell, our telomeres would still shorten at the same rate. Of course the ...


2

The sort of thing you're talking about would be called a Life History Invariant: a dimensionless ratio between two life history traits $A$ and $B$, such that although the traits themselves vary widely between species, the ratio $\frac{A}{B}$ is relatively constant. Eric Charnov has written a lot about this, including a book. One of the invariants which has ...


2

Your first question appears to be answered (tentatively, at least) in the article you linked to... "Traditional" estimates based on slow, reptilian growth rates, combined with the enormous size of dinosaurs, led scientists to conclude it could be up to several hundred years. However, palaeontologists today believe that dinosaurs grew much more ...


2

Not surprisingly, the WHO has a lot of data, I think especially interesting for you is this interactive figure, which you can find here: Other data on this topic can be found on the WHO website here, in the Wikipedia or from the Worldbank.


2

Some of the permanent microbial flora inhabiting the skin protects the host from other pathogens. The complex host– microbe and microbe–microbe interactions that exist on the surface of human skin illustrate that the microbiota have a beneficial role, much like that of the gut microflora. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2746716/ It is apparent ...


2

because some skin cells which are alive , secret fat and other materials , these materials make the skin acidic , and acidic environment is not good for many germs , on the other hand , there is an enzyme in sweat (lysozyme)which destroy the wall of bacteria


2

Another example is the paired helical filament of Alzheimer's disease, so-called because neurofibrillary tangles have a ribbon-like structure when viewed under the electron microsocope. It is now accepted that paired helical filaments consist of a single protein, microtubule-associated protein tau, in a polymerized and hyper-phosphorylated state. (see Lee ...


1

If you mean to ask whether or not humans will be able to continue increasing their life expectancy without an upper bound, the answer is no. If you're asking if people live longer now than in the past and whether we can expect to see further increases, I'd guess that the answer is yes for most of the developed world, with the exception of the United States. ...


1

One reason for that delay in onset of cardiovascular disease could be that women are relatively iron-deficient compared to men — especially younger women, those in their late teens and early 20s — because of menstruation. Iron plays a very important part in the reactions in our cells that produce free radicals, which damage cell membranes and DNA, and may ...


1

Even in perfect environmental conditions we would age. Living is associated with a myriad of deleterious processes, both random and deterministic, which are caused by imperfectness, exhibit cumulative properties, and represent the indirect effects of biological functions at all levels, from simple molecules to systems. Here is a good read on this topic https:...


1

Fireflies 'glow' in larval and adult stages but for very different reasons. It is thought that glowing behaviour first evolved in larvae to deter predators(Branham and Wenzel (2003)). This is an example of an aposematic warning, which uses bright colours, smells, sounds, or in this case light, to tell predators they are undesirable as prey. Sometimes a prey ...


1

It sounds reasonable that reducing the physical stress on a body would reduce the wear and tear, and thus increase the owner's lifetime. However, it's just as reasonable that human bodies are designed to be under stress, and drastically changing the environment will harm the body in subtle and even obvious ways. For instance, some research shows that lung ...


1

There are certain annual(eg.peas) and biennial plants(eg.carrot) also which die at fixed times. But for perennial plants : From this Trees endure as long as they do basically because they're nonhierarchical organisms. In animals, all vital functions are controlled by the central nervous system, the guiding element of which is the brain. When the ...


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