Does sacrifice contradict evolution?

Question

Is this an observable phenomena in nature(I seem to think so but i cannot find any examples)? Examples will be great.

Answer 1

No, sacrifice does not contradict evolution.

Simple example, many insects and arachnids (e.g. the male praying mantis or male black widow) will quite literally sacrifice themselves to mate ... they become a nice meal for the female afterwards, but their genes live on.   The male praying mantis will actually continue to copulate *while being eaten*!

Bees will sacrifice themselves for the hive.  The very act of stinging a threat is usually fatal to the bee ... so clearly there is an evolutionary advantage beyond survival of the individual bee.  Namely, survival of the hive with other genetically related bees.

Many birds and mammals will put themselves at risk to protect offspring.

True story (warning: sad):  My g/f and I were driving on a busy freeway when we were horrified to see a mother duck with several ducklings marching right towards the freeway.   I stopped and we jumped out of the car to try and redirect the mother duck back away from the freeway.  But she, perceiving us as a threat, shooed her ducklings into the short grass, and then took off in the opposite direction, flying right into the windshield of a car.   We were able to gather the ducklings into a shoebox, and took them and the fatally wounded mother to a wildlife hospital (the mother didn't make it but the ducklings were OK).  The point is that the mother duck clearly tried to hide her young, and then protect them by flying towards danger (us and the freeway).   What was the evolutionary advantage?  7 ducklings with her genes.

Sacrifice does not contradict evolution in any way because evolution is not just about survival but about *reproduction* ... all that matters (as far as natural selection is concerned) is whether you pass your genes on.   So if there is some instinct that ensures the passage of genes, even at the sacrifice of the individual, then that instinct will propagate.

Answer 2

Altruism (the science-y) word for self-sacrifice has been difficult to explain.  But, when scientists carefully look at instances of supposed altruism, they generally find a self-serving purpose.

There are a number of instances in the animal kingdom (esp. in insects, mammals, and birds) where some individuals will forgo their own chance at reproduction in order to advance the reproductive capacity of others.  How could this ever be an evolutionary stable strategy?  The genes for non-reproduction would die out in a generation.  It turns out that when these instances are investigated, the individual being given the help is genetically related to the  one providing the help.  

About 10% of bird species show this kind of cooperative breeding where the non-breeding helper is usually the yearlings from mom's brood last year.  So, by lending mom a hand, they're assisting in the survivorship of their siblings (probably half-siblings) who share their DNA.  

Evolutionary biologist modelers, in fact, have even modeled out the ideal strategy based on the likelihood of genes being passed on.  Siblings share 50% of their genes.  Therefore, if you, a young, inexperienced breeder, might only be able to rear one successful offspring of your own (who would have 50% of your genes), you might be better off helping your parents raise two more siblings.  Overall, more of your genes will be making it into the pool.

Answer 3

Secretsauce's answer is - as usual - tip-top.

For further information, look up "kin selection" and the "gene-centred theory of evolution".

Kin selection is the phenomenon where two siblings will collaborate in order that *one* of them find a mate (eg - two male birds performing a mating-dance, even though only one of them will get to mate with the female).

And the Gene-Centered view of evolution (aka the "Selfish Gene Theory") is the hypothesis which explains this, and the phenomena that Secret mentioned.

Answer 4

No because you are protecting those with similar genes to you. So your gene line might still be passed on.

Answer 5

Altruism has nothing to do with evolution. If you think survival of the fittest means that the strongest and biggest one wins, you are mistaken. Survival of the fittest has to do with adaptations to the environment caused by genetic mutations.

Humans, apes and chimps are the only social animals that behave altruistically.

Chimps get food for their entrire tribe and not just themselves.

Chimps do that picking the bugs off their partner's back thing.

Other animals "sacrifice" themselves for their offspring. Like a mother protecting her young eggs or babies.

So I guess it is observable in nature. But sacrifice in the way you meant it does not contradict nature. It is a part of nature.

It's instinct to want to protect your offspring.