what are examples of natural selection in the envierment?
445462
Say you have a species of beetle.  There are two color types of the same beetle, say a lighter colored one, and it has a few darker colored beetles here and there.  The lighter colored beetles blend in better with their surroundings, so the darker colored beetles have a tendency to be picked off by birds or whatever.  Say a volcano erupts or something, and it causes a dark ash to settle all over everything, then the darker beetles will blend in more with the environment than the lighter ones, and then you have a population surge of darker beetles, because they are more suited to the environment.  Make sense?  I know what I'm talking about, I just can't describe it very well!
328841
Natural Selection is a process where the weaker individuals are "culled out" and only the stronger ones survive.  A good example of this concerning bacteria is the overuse of antibiotics.  Eventually, the resilient individuals will survive antibiotic treatment and become resistant to that particular antibiotic.  Eventually, that population will grow enough and be untreatable with that particular treatment and another antibiotic will have to be used.  Some speculate (myself included) that this is how Bird Flu was created except on a viral level instead of bacterial.  In summary, new environment (heat, cold, antibiotics, etc.) weaker bacteria die off, strong ones survive and propagate and therefore, live on. . . thus adaptation.  Hope this helps.
179265
Everything in nature has a cause, but I would contest it having a purpose. Natural selection could be described as "purposeful" in a sense because it benefits those species that can adapt to changing conditions and compete for limited resources. But the mechanism is pretty well explained and doesn't require conscious, supervisory intent. \nHurricanes happen for pretty well known causes too, and to impute a purpose in this case is a much longer stretch. But if it is absolutely required to define a purpose, you could say that hurricanes aid evolution by placing unusually high stresses on most life forms that experience them. If overpopulation has reached resource-threatening levels, this may be ultimately beneficial to a species, aiding the selection process if it doesn't wipe them out.
272274
let's see...\nAccording to Darwin, natural selections is when species born with a trait that's slightly different from what they are supposed to be turn out to have a bigger advantage in life. Because it's successful, it breeds, and the trait is passed on to the next generation. Eventually, that trait dominates the species in a way that we identiy them as a new or different species. \nIn the case of hummingbirds, the flowers they feed on also evolve with the birds. As we all know, hummingbirds have prett long beaks. To 'protect' their nector (or something), flowers start to grow more in a 'tube' shape, which prevents species like bees to get the nector. In response, hummingbirds evolve by growing longer beaks so they can still get their food (drink?)
916499
I don't know why you asked the same exact question 3 times.  I gave a full description in another post.\nhttp://answers.yahoo.com/question/index;_ylt=AmiwcqFgnMC2QHEoVOkL3y_zy6IX?qid=20061127161951AALL9zd\n\n... But on the assumption that this is some school question or project, I'll try and compress all the evidence into just four main categories:\n\n1. Evolution reproduced in the lab or documented in nature, including the basic mechanisms of natural selection established in artificial selection (like breeding).\n\n2. Fossil evidence. \n\n3. Genetic and molecular (DNA) evidence.\n\n4. Common morphology and proteins (vestigial, homologous, and atavistic structures and proteins). \n\n5. Others (OK, that's 5 ... but I needed a place to include things like bacteriology, virology, imunology, embryology, biogeography).\n\nAgain, these are just the names of the *categories* of evidence ... for details, see my other post.
323144
This is Darwin's Theory of Evolution known as natural selection:\n\n1. Species have great fertility. They make more offspring than can grow to adulthood. \n\n2. Populations remain roughly the same size, with modest fluctuations. \n\n3. Food resources are limited, but are relatively constant most of the time. From these three observations it may be inferred that in such an environment there will be a struggle for survival among individuals. \n\n4. In sexually reproducing species, generally no two individuals are identical. Variation is rampant. \n\n5. Much of this variation is heritable.
1071975
the things you say (or the article said) seem to be true about evolution because the hypothesis is so plastic...however, it is falsifiable and it has been falsified; it has made numerous predictions that have failed miserably\n\nnatural selection is real, it happens\n\nnatural selection does not help evolution\n\nthe reason being that information must first exist to select from\n\nnatural selection can explain the survival and extinction of organisms...but it can not explain the original arrival\n\nfor evolution to be true you need a net gain of highly specific complex information (which first of all has never, at least not in our experience or observation to date, been the result of random processes; it has, in all of our observation thus far, always and only been the result of intelligent mind -- sa information science) however natural selection always results in a loss of information...some info is selected (kept), and some info is neglected (lost)\n\nbut first you gotta have all that info to select from\n\nand you better start out with a lot of it if you're going to be selecting some and neglecting some every generation\n\nwhich still leaves the real problem...where did all that info (that natural selection selects from) come from in the first place
1096462
A is incorrect because this statement is usually attributed to Malthus however, Darwin was aware of this and it is one of the driving forces of natural selection-- that there are more organisms (not just humans) that can be supported by available resources.  \n\nB is incorrect because the adaptations that are favorable are not always biased towards being swift and aggressive.  There are passive, defensive adaptations that are effective.  \n\nC is incorrect because evolution is not directional.  There is no such thing as devolution.  A trait that is advantageous under one set of conditions may be a liability under different environmental conditions.  The most successful organisms on this planet are bacteria.  Also, individuals do not evolve.  Populations evolve.\n\nD is correct.  It is even right there in the title of Darwin's book on natural selection.  Look it up and read it.
1037290
Natural variations are variations that are often the result of random mutations, that arise when cells divide during development of new organisms. \nWhen these organisms reproduce, they pass on these variations to their offspring – inheritance of natural variation. \n\nOrganisms can vary in size, coloration, ability to fight off diseases and countless other traits. These natural variations and their ability to be inherited makes it  possible to survive as a species.
947619
1. All organisms tend to produce more offspring than can possibly survive (Darwin's generation gave this principle the lovely name of "superfecundity").\n\n2. Offspring vary among themselves, and are not carbon copies of an immutable type.\n\n3. At least some of this variation is passed down by inheritance to future generations. (Darwin did not know the mechanism of heredity, for Mendel's principles did not gain acceptance until early in our century. However, this third fact requires no knowledge of how heredity works, but only an acknowledgment that heredity exists. And mere existence is undeniable folk wisdom. We know that black folks have black kids; white folks, white kids; tall parents tend to have tall children; and so on.)\n\nThe principle of natural selection then emerges as a necessary inference from these facts:\n\n4. If many offspring must die (for not all can be accommodated in nature's limited ecology), and individuals in all species vary among themselves, then on average (as a statistical statement, and not in every case), survivors will tend to be those individuals with variations that are fortuitously best suited to changing local environments. Since heredity exists, the offspring of survivors will tend to resemble their successful parents. The accumulation of these favorable variants through time will produce evolutionary change. \n\nhttp://www.mc.maricopa.edu/dept/d10/asb/anthro2003/origins/selection/fullhouse.html
686544
large gene pool\n\nrandom selection
194840
"Natural selection' is the metaphor chosen by Charles Darwin in 1859 to describe what he proposed to be the major force driving the evolution of new species and of those organismic attributes that allow life forms to negotiate their normal environments better than others (see Evolution, Adaptation). Along with the rules of inheritance, discovered by Gregor Mendel at about the same time, natural selection provides the fundamental mechanistic foundations for modern evolutionary theory"\n\n\nI'll say what I said in another question you asked only I'll be a little more brief here.\n\nspecies evolve within their own species but they will never evolve into another species.
599194
charles darwin proposed theory of natural selected or DARWININISM.It states:\n1.Despite having enormous potential of fertility, the population size of any kind of organism remains within a limit.\n2.It is due to the struggle between members of same species and different species for food, space and mate.\n3.The struggle eliminates the unfit individual.(survival of the fittest).\n4.These favourable changes when accumulated for a long time lead to origin of new species.\n\nHope it helped
63723
unfortunatly there is none for the emergance of species that can be observed. natural selection can be observed and has been but there is no conclusive evidence that evolution took place.
134758
Oh no, not this question again. Why doesn't anybody use the Search button?\nLet me address two separate issues (the first part is modified from another answer):\n1) The pattern of evolutionary processes that can be seen (in the fossil record and living species)can be of two types: \nIn _anagenetic_ (meaning "that generate upward movement") events, an entire population evolves in one direction and becomes so different that at some point the people who study it give it a different name. This is encountered in paleontological research and the decision to separate one from the other is ultimately arbitrary. \n_Cladogenetic_ (meaning "that generates branches") events entail a population that splits into different sub-groups; each of these then evolves independently from the others. We share A COMMON ANCESTOR with living apes, but we have not evolved from them directly. \nOur direct ancestors are fossil hominid species. \nAll the species that are living today have their separate evolution and history; also they all (including humans) share common ancestors from which they (we) have inherited our common traits. And apes have their own ancestors that are closer to them than to Homo sapiens; the fact that apes are our closest living relatives does not exclude the existence of more related _extinct_ relatives.\n\n2) What you're stating is one of the arguments that many creationist use, namely, that change within a species (adaptation, i.e. microevolution) is possible (they are astute in not denying this, because the proofs are overwhelming!), but a species cannot transform into another (macroevolution). \nThis is based on a mistaken concept of "species". Most people think in terms of the biological species concept, which is based on reproductive isolation. That is, individuals of each species cannot hybridize succesfully with individuals of other species. However, there is not a single path for the rise of the mechanisms for recognition or isolation that we perceive as the "real boundaries" of a species (see second link for an interesting discussion here at Y!Answers). What the taxonomist calls a species may respond to different species concepts (such as morphological, evolutionary, biological (isolation), paleontological, recognition, etc,), and there are many examples of populations in which speciation (total isolation) is on the way, and there's a thin line between "subspecies" or "geographical races" and valid species (just ask an expert in systematics, which I am not). \nEvolutionary processes are long-term phenomena, and it may seem that there are "evolutionary leaps" from one species to the other. But although there are particular cases of "instantaneous speciation", most of the "leaps" are due to the fragmentary nature of the fossil record. So many populations become extinct or become something else and their former existence is not recorded anywhere! But although the record is fragmentary, life is continuous.\n\nSorry for the lengthy answer, I hope you find it useful.
209928
i havent heard that example, but its possible. that would possibly fall into the category of microevolution...like when birds beaks get bigger or smaller to crack different nuts. its still a bird, with slightly different attributes. that would be an example of artificial rather than natural selection though, since it would be people choosing what they think is attractive, rather than nature killing off people who were less well equipped to deal with the environment.
886021
Evolution and the means to survive.