Why has evolution allowed us to survive with so many fundamental weaknesses?

Question

In a purely"Survival of the Fittest"setting,I imagine our ancestors sleeping,eating,digesting food,mating,gestating,giving birth and being born but as a result of these activities being prone to attack and therefore more likely to lose their life.
It seems to me that the most successful organisms should be very sturdy - even if they suffer damage in some small way,they can still carry on as though nothing has happpened; should be ones that contain both sex organs in one body so that no unnecessary contact with other members of the species is required; can make use of their immediate environment for food, water, etc; should be able to withstand relative weather extremes; should live a very, very long life, producing many offspring. So why do we seem to be at the top of the evolutionary tree and not trees themselves (especially since they are used as a simple and elegant model of evolution.)
I'm probably being very obtuse, but I AM new to evolution and maybe don't know as much as you.

Answer 1

its a complex question with a simple answer.. life just easier than you are giving it credit for.. if life were more difficult, then perhaps such evolutionary developments like you are suggesting would be necesary

Answer 2

There is no "why" to the process of evolution. It is simply a process that occurs. Just as there is no "why" is there gravity.

Gravity "happens." And when gravity happens, certain things occur. The physical world falls into place as a result of the rules, the so-called "laws" of physics.

Evolution is not different. It occurs as a result of various factors that either occur or do not.

So, while there is no conscious thought taking place that will cause humans to survive the travails of living in the wild, there is a "reason" attributed to this particular circumstance. That reason has already been given by another person responding, and, that is, that the human brain had evolved to the point where it's talents and strengths were able to compensate the human body's weaknesses.

A lone, naked human would be no match for a hungry, healthy lion. but a human, armed with a pointy stick has a much better chance. Even better, yet, SEVERAL humans, armed with pointy sticks can take down a lion with almost 100% certainty.

Tool-making and cooperation are rather higher orders of thinking. Some animal do one or the other. Few animals do both. Only humans have brought those talents to the level we use today.

There is no "why." It just is.

Answer 3

Genetic recombination, as obtained through sexual reprodution is one of the most successful evolutionary strategies. It allows traits to be blended. The successful offspring tend to have favorable traits. The unsuccessful tend to have unfavorable traits. Why not hermaphroditism? Most simultaneous hermaphrodites seek mates because of the benefits of variety. Additionally, we lose the benefit of male/female dimorphism, which was useful in a hunter/gatherer economy and retained utility in agrarian economy. It is probably outdated in a post-industrial economy, but the next few thousand generations should tell.

All of those "sturdy" features you suggest take energy. If we were built like bison, we'd spend our whole day eating. Being able to exist in all environment (without the use of tools) means optimization for none. Producing one offspring that reproduces per adult in the previous generation allows a steady population. More allows growth. Too much more and you get overpopulation which places a strain on resources.

As for the evolutionary tree, it is called such because of its branches, just like a family tree. If you draw it as a function of time with the start of life at the bottom and the present at the top, we are at the top along with everything else that is not extinct.

Answer 4

Because "survival of the fittest" is a misnomer; it should be called "survival of the good enough." Even with billions of years of evolution the appearance of a "perfect" organism is unlikely, and if the environment changes after reaching this ideal it's no longer perfect anyway.

Two creatures do come to mind though which seem to be about as well-adapted as it's possible to get. Sharks and cockroaches live in environments which haven't changed much over millions of years. In their case, any mutations at all will make them less fit than they already are, so it appears that evolution has stopped for them.

Answer 5

evolution within a species is not in dispute however its resulting in new species is still a theory.
who ever said that we are more highly evolved than trees. it is not that kind of competition. trees and humans both have many biological enemies that are sure to kill them off at a pretty good rate. these "weaknesses" to the individual turn out to be strengths to the species as they are what spurs the evolutionary process. If all or nearly all survive then the fittest cannot be naturally selected.
you don't have to know that much about it to understand the process. as long as a species has sufficient weakness and variety to distinguish the fit from the unfit, the process will pass on (to a greater degree) the superior traits.
the shark and the tortoise has proven to be very well adapted to their environments have have for the most part stopped evolving. good for them, but like the dinosaurs, they be be so well suited and with insufficient variety so that they may not be able to adapt to a change in their surroundings.
it is because of our "weaknesses" that we survive.

Answer 6

"Top of the evolutionary tree" is just our opinion. For all we know, the trees see it differently. They have been around longer than us, for one thing.

Other creatures that use the sorts of simple, robust survival strategies you describe do, in a sense, predominate - we are hugely outnumbered by both insects and bacteria.

Each species is not in direct competition with every other species, only with those with identical needs. So all that is necessary is that a species find an ecological niche where it can survive without being out-competed. And each species has its own strengths and weaknesses. We humans compensate for our fragility by being adaptable, and by being able to anticipate and predict, among other things.

Answer 7

Our survival tells you one very important thing - that your assumptions about what you consider our fundamental weakneses are wrong. You need to be very careful about what you consider an "unacceptable risk" in evolutionary terms.

Take, as one example, your assertion that a successful species should live a very long life with many offspring. This may seem desirable to you, but in evolutionary terms it is simply not necessary. Genetic survival can be served by a short life provided it leads to successful reproduction - a long life could be very expensive in biological terms, and carries no evolutionary benefit.

Answer 8

Our weaknesses are overcome with brain power. 350,000 years ago when we were cave men evolution was a little faster because the life expectancy of a human was only about 30. so most births would have been teenage births. The human body even now only grows for 18 - 25 years, after that time it is simply maintained (that is to say, you're left slowly dying).

It seems the whole point of life is to evolve more, possibly to the point where we can evolve ourselves?

Answer 9

The rapid evolution of our governing organ, the brain, is most responsible for slowing our physical evolution. Since we conceived of armor, evasive tactics, weapons that work well at a distance, and so on, becoming physically "tougher" has taken a back-seat. The evolutionary down-side to being hermaphroditic is the lack of variation in genes that that would encourage; the very strength of evolution lays in its intermingling of genetic material giving a wide variety of outcomes, some of which will inevitably give the bearer an advantage.

Answer 10

Survival of the fittest is true from a neo-Darwinian point of view. But why has man survived is your real question given his many weaknesses: his knees and back orthopedically and his lack of fur dermatologically are just two of many human weaknesses. The answer is man's ability to adapt e.g. his ability to make and use tools. In the cold, man hunted bears and used their fur, found out that fat in the diet helps to maintain internal body temperature and energy level. In the Himalayas, Sherpa's have developed greater capacity lungs for the thinner mountain air. In equatorial regions, the skin has evolved (from earlier adaptation) a darker color to obviate ultraviolet pathology. Our feet have adapted to be able to walk over uneven terrain; we humans can run for very long distances (when in proper physical condition) to weaken larger and faster animals. These are just a few of man's adaptations. By far, the greatest is his cranial capacity to outthink lesser animals ie adaptation.

Answer 11

On the contrary, we have been created with amazing design everywhere we look. For example DNA is by far the most efficient information storage mechanism known.

Far from evolving we are in fact devolving. The genetic genepool is deteriorating. Evolution requires a growth of genetic information. What we observe is a reduction in genetic information.