why do we die?

Question

im asking for a scientific answer not a philisophical or religious answer.

i can understand the life process all the way up until reproduction but why do we continue to age and then die?

Answer 1

Aging is caused by the shortening of telomeres. Every time our cells reproduce our DNA is shortened. We have telomeres (long sections of repetitive sections of nonsense code) to protect our vital DNA from being left off in reproduction. The longer we live, the more our cells reproduce, the shorter our telomeres get. When we start losing our telomeres and our DNA starts getting shortened, it causes genetic mutations which then cause health problems (anywhere from kidney and heart disease to cancer.) This is why we age and die...barring of course diseases and accidents which have nothing to do with aging.

Answer 2

Evolution is not about what is better for the individual. It is what is better for the species as a whole. By dying, you free up resources for your offspring and increase the numbers of generations. If generations were too long, evolution would be slower and other animals would likely eventually out-evolve you if that is a word.

Answer 3

shortening telomeres are one cause of aging, oxidative stress is another. there may be various causes, but fundamentally there can be no natural selection pressure for immortality - reproduction already ensures the near immortality of genes, and unfortunately for us, it's the genes that are important in evolution, not the organism.

Answer 4

Science is limited on things. You can't answer everything in science. Can you prove that there are no mammoths on earth? No, because you need to look everywhere.

Its hard to answer question scientifically.

P.S. There isn't any proof that evolution exist. Its another kind of religion.

# ARGUMENT FROM THE 2nd LAW OF THERMODYNAMICS (I)
(1) The Second Law of Thermodynamics says that a closed system tends to disorder.
(2) The universe is closed and ordered.
(3) Therefore, God exists.

Evolution disproves the cell theory: All cells comes from living animals.

Answer 5

We die because of hundreds of reasons. Ultimately though it is because our brain (which makes us who we are) does not recieve enough nutrients and oxygen and therefore dies. Without oxygen and nutrients the brain cannot maintain itself, it begins to be destroyed by either intracellular mechanisms such as the ischaemic cascade leading to apoptosis, or sheer physical forces such as by oxidative reactants. Once the brain is unable to maintain itself it dies, and we die with it. After all, we are our brain. There are plenty of reasons why the brain would die - all results in loss of nutrients or inability to maintain health of the cell. Most deaths occur due to infectious disease or malnutrition. If we are lucky enough to survive these then other things will set in such as cancer or heart disease (quite depressing!!). It has been said that cancer is the natural end to all multicellular organisms. This occurs because the DNA in our cells acquires more and more mutations until it becomes useless. These changes are not under our control and are inevitable. Eventually we will be unable to repair DNA good enough, our cells will lose their ability to maintain their health and they will die. This could be a neuron, a heart cell or anything! If its a cancer, the cancer will grow, invade surrounding tissues, destroy them, block vessels, destroy the brain, and so we will die. Infectious diseases have a similar effect, they destroy our cells etc. You can probably appreciate why people die from heart attacks and other such mass physiological catasrophes. So eventually, it is either acquire mutations in DNA, or massive physiological catastrophes which kill us/age us.

So lets look at a heart attack. We accumulate fatty acids, cholestrol and lipids in our blood leading to atheroscleorisis causing the coronary arteries supplying oxygen to our heart to narrow. Because the heart does not recieve enough oxygen the heart begins to die. The heart, dead now, cannot deliver blood to the brain. Because the brain cannot get oxygen and nutrients the brain begins to die. The brain dies under a cascade known as the ischaemic cascade. This is due to the lack of nutrients, cells are unable to maintain normal cellular environments and they begin to commit suicide (known as apoptosis). The brain dies and we die. If they dont commit apoptosis then because of lack of nutrients the cell will be unable to maintain itself and will die due to dyfunctional proteins and DNA. Without some sort of energy input (from nutrients) the cell becomes more and more dysfunctional until it is useless.

To conclude, we age because of acquired DNA mutations that we are unable to repair, or tissues we are unable to replace. And we die because our brain dies due to aging

I've tried to keep this very basic. If you want to ask me questions feel free by email :)