How can new combinations of traits increase or decrease an organism's chances for survival?
594843
Recombination (I presume this is what you're talking about) can do both. It creates new combinations of alleles at different gene loci that might be especially advantageous in a particular environment. The down side is that it can separate them also, so a parent that has a good combination will produce some offspring that don't have the combination because recombination has separated them in the gametes.\n\nI hope this is what you were asking about.
805249
Of course. It lead to genetic isolation, then evolution which gave us new species. Look at the ratities as an example.
475300
You cant really guarantee it, but I am sure it can be argued that it could be a solution. This example that I am gonna give is gonna be really vague, but there could be a way to speed up the growth rate of gen modified food and therefore creating more food to eliminate hunger and starvation. It could also be made to resist certain unfavourable conditions that could make plants resist extreme temperatures. I heard of [i think] strawberry being grown in warmer climates becuase they are gen. modified (Their preffered climate is in colder areas). I cant remember much about it tho.. I got this from my bio teacher.... it could be a possibility.
336439
Mutation generates differences.  Most mutations are deleterious and natural selection tends to eliminate them quickly.  Many are neutral and are retained to some degree because there's nothing weeding them out.  A few are positive and variation is also lost in that case because selection will eliminate the other variations.\n\nThere is a process called frequency dependent selection whereby a trait is advantageous but only if its rare.  For example since hosts adapt to a certain kind of parasite, it is advantageous for a parasite to have rare characteristics.  That way the host is unlikely to have seen that model before and the parasite is likely to be successful.  In that case selection actually favors a lot of versions in a species because as soon as anything become really numerous it becomes deleterious.
931077
It's well accepted that the larger the gene pool, the better chance a species has of adapting to change and surviving famine, disease and other disaster.\n\nCulturally, we're no different. The larger the variety of options we have, the better our chances for coming out of a disaster well. Cultures and empires last centuries, so it's hard for us to see this happening in our society. But we still need that diversity for our collective well-being in the long run.
1110389
Species do not evolve, individuals show variation and sometimes that variation is pro reproductive, (not necessarily pro long and happy life)  In that case a pool of individuals with that trait grows and reinforces it.  Such variation tends to be absorbed in a large mobile population and cause no long term divergence, so our own mobility and global success works against a new variety of human emerging.  \n\nOne can anticipate however that our science will progress far faster then any normal evolution and in a short time a group of therapies will be available that will offer longer life, greater vitality and sexual enjoyment, improved health in general and whatever appearance is desired.  The trend to these things already exists.  The factor that will isolate this group of advantaged humans may already exist as well, since it is likely that such biological tinkering will be available only to those who can afford it.  We may see the very rich diverging as a virtual new type of human in the next fifty years, followed by the middle class in places like America.  The difference in lifespan between a wealthy nation and a third world one is now twenty five years or more, it may stretch to a century.  A pretty big issue putting wealth and experience against endless numbers...
1040926
Accident. Coincidence. Chance. These shaped the universe as we know it. Organisms have slowly evolved and become humans as we are today... And we've stopped evolving almost completely because we've learned that, rather than adapting to our environments, we can adapt our environments to US. We no longer need changing survival skills for heat or food, because these are grown and raised and manufactured for us... and this will probably be our eventual downfall. If ever we are failed by technology, our inability to adapt and grow and evolve will cause us all to perish.
703467
Through a variety of mechanisms, gene flow, mutations, etc... allele frequencies in populations change over time. Some genes are favored while others are not this is how selection and evolution, as it were, work. \n\nSay that there is an organism that has two dominant phenotypes, one green and the other bright purple. If for some reason being one color or the other affects that organisms ability survive and reproduce, then organisms with the preferred phenotype will end up creating a larger percentage of the offspring that those without it. IN this way the population will be directionally selected towards the "preferred" phenotype, in this case say purple makes you more attractive to mates so therefore you reproduce more than others of your species that are green.\n\nThe interesting thing is that this is not a one way street and there is no end... this is because the environment is always changing and what was preferred before might be selected against in the future. In this way DNA is always and will always be changing and in that way evolving.
325191
Actually it makes perfect sense.  Things naturally pair together, whether it be by gravity, magnetism, parasitism or whatever reason.  eventually enough atoms will link together for convienience to form a protein, enough protiens will link together to form a cell, then we have life.  cells will then pair together to form tissues, which will pair with other tissues to increase their survival rate giving us more complex organisms.  See the steps yet?  Following that we get to higher functioning organisms.  An organism's cells reproduce millions of times in that organisms lifetime and every time the DNA is replicated there is a chance for a mistake.  How many typos do you make typing a paper?  This is where variation comes from.  Evolution and extinction come from natural selection.  As the world changes things have to adapt those that don't die. If they didn't die we wouldn't call it evolution.
171371
Should natural disaster occurs, natural selection occurs, as the species that adaptable enough to survive the natural disaster will continue their existance and those which not adaptable enough to survive these will be wiped out from the area.\nThose which able to continue their existance will inherit the traits that enable them to survive the natural disaster and of course, those who cannot survive will not have a chance to inherit their traits. \nThose will results to the increase of the "resistance" of the surviving species to the same natural disaster.
491745
"Survival of the fittest" is indeed a misleading formulation. There is no absolute measurement for fitness - what makes you more likely to survive today might hinder you tomorrow and vice versa. So it is not like everything is striving upwards that previously determined fitness slope. Therefore many of the interpretations of Darwinism from early last century where wrong. You can't derive rules from evolution like "society should weed out weak indivudals" or stuff like that. \n\nIt follows that the only thing that really matters in terms of evolution is to survive, or more precisely, to exist. Personally I go as far as to say that "reproduce as much as possible" is not the only strategy. I consider stones as a special case of evolution - they manage to survive for a very long time, too. I see evolution as just "the likely thing will happen".\n\nAs for dropping dead: it is not the individual that evolution operates on. It is the population, ie the gene that evokes a specific behaviour. Death can also be predetermined by evolution, because it might be benefitial for the population.\n\nEdit: in reply to your additional comment, thanks, and I am not saying that death is necessarily always a good idea. Humans live quite long, probably also because they are costly to manufacture. Insects don't live very long, but are also very successful. We humans are free to set our own goals for life, and if it is to live long and well, so be it. The ones who figure out how to live longer will live longer ;-)
163988
The four priciples are:\n1. More individuals are born than survive to reproduce \n2. Heritable variation exists among individuals \n3  Struggle for existence or competition\n4. Adaptation
413080
Your understanding of the evolutionary process is flawed. Evolution means "change in hereditary features over time".  We do not develop structures in order to adapt to our environment.  Rather, through subtle or obvious genetic variation in offspring, those offspring who are most successful in the current environment will live to maturity to reproduce and pass on their genes.  For example, if the environment of polar bears becomes warmer, so that areas of the land have soil showing, a baby born with a slightly mottled coat might have better luck at camouflage -- better luck at hunting -- stronger chance of breeding and passing on the mottled coat genes.  Over many, many years, there would be a shift away from genes for all-white coats towards more genes for mottled coats.  So -- since watching TV does not affect survival and production of successful offspring, we would not expect one type of eyeball to be better suited than another.
237532
if the environment changes faster than the organisms ability to adapt to the changes, the species will go extinct. The reason, be it man made, or natural, is irrelevant. The point is, there is a change, and the organism cannot adapt.
1186604
One answer might be that they have gradually changed, or evolved,over a very long time to suit the places they live in and the food that is available to them.\n                 In the 19th centurya scientist named CHARLES DARWIN (1802-1882) put forward a theory, which he called 'natural selection'. to explain how these changes might happen.\n              According to darwon, individuals animals and plants sometimes have qualities that help them to survive.For example,in agreen forest, a green bug would pribably survive longer than a brown bug,because its appearence would help it to aviod being seen amd eaten.\n       The individuals that survive the longest are likely to have more babies,and will pass on their useful qualities to them.Over a very long time,each species will very gradually develop all the most useful qualities for surviving in its own habitat.
374098
Obviously you dont know how things work.\n\nCheck this out, a fish cannot give birth to a different species fish. What if a mutation occurs and the fish has a extra fin? Due to natural selection that fish is better suited to the environment, and mates more and the mutation becomes more often, vwooleh, we have a new species of fish assuming the other just pure breeds or it has migrated away.\n\nWe all started very basic, that basic thing mutates and mutates into say 10 basic things, those basic things become more complex and so those 10 basic things multiply into 100 more complex things each only breeding within its own mutation.
111422
Come on, you've got to do SOME leg work here.  Those are huge subject areas.  Where would we start?\n\nOK, Darwin: Natural selection acts on random variation.\n\nLamark: Acquired characteristics can be passed on to the next generation.