How can concepts of evolution explain these changes in populations over time?
547976
Um... were you "created"?
1017223
If we talk about Evolution Theory, a number of them have been formulated till now, for instance, by Lean Bapist Lamark, by Charles Robert Darwin, by Earnest Hackel, by Hugos de Veries....\nBut in general, the probable evidences, which might have stimulated these gentlemen to formulate their Evolution Theory are,\n1) Fossils - Missing links, and connecting links\n2) Homologous organs\n3) Analogous organs\n4) Vestigial organs\n5) Embryology\n\nAnd apart from these, we can take into consideration, "Physiology ".
1042707
"In biology, evolution is the measurable change in the heritable traits (allele frequency) of a population over successive generations. Evolution is ultimately the source of the vast diversity of the biological world. Over time, it may result in the origin of new species (speciation). Contemporary species are related to each other through common descent, products of evolution and speciation over billions of years." translation organisms change over time due to adapting to their environment and selective breeding, though natural selection plays the largest role in evolution, in natural selection the animal that is best fit to live in  and survive in its environment will be able to live on and reproduce. Also known as "survival of the fittest"
642511
Evolution is a scientific theory that explains the origin of the diversity of species (note that it does not, and is not intended to explain the origin of life). The basic idea of evolution is that mutations result in genetic diversity in a population, and consequently different traits, and different selective pressures favor certain traits over others. In a diverse population, some individuals are better suited to the environment than others, and the individuals that are better suited are more likely to survive to reproduce and thus pass their genes on to the next generation. Consequently, the next generation will have more of the "good" genes and fewer of the "bad" genes than the generation before it. Because the environment is constantly changing, the definition of "good" and "bad" genes is also constantly changing. Something that used to be an advantage can become a disadvantage, and vice versa. More often, however, neutral traits will become either good or bad. Changes in environment can include not only changes in weather or resources, but also competition from other species.\n\nAs the environmental pressures change, the population of organisms changes with it. Over time, the little changes start to add up, and eventually the population will be so different from the ancestral state that it will be considered a different species. The diversity of species results from splitting of populations. If a population is separated by some geographical or reproductive barrier, the two subpopulations will likely evolve in different ways, to become two separate species. Eventually the two species may be reunited, but they will no longer be able to interbreed. Instead, they will compete with each other, and likely diverge even more.\n\nThe theory of evolution is supported by considerable scientific evidence, and is accepted by the vast majority of the scientific community. It is the ONLY scientific theory currently in existence that explains the diversity of species. Some people claim that "intelligent design" is an alternative theory for the origin of species. However, intelligent design is not a theory in the scientific sense. It is not supported by scientific evidence and can never be tested experimentally (not because we don't have the tools yet, but because it is theoretically impossible). Intelligent design provides an alternative to science, not an alternative scientific theory.\n\nScience is not about finding a single piece of evidence to conclusively prove a theory. It's about constructing theories to fit the existing evidence and gathering new evidence that supports or refutes existing theories. Evolution is supported by a preponderance of evidence. While no one point conclusively proves it, when all the evidence is considered in the context of existing scientific knowledge evolution is a well substantiated theory. Intelligent design is not.  What follows are brief explanations of some of the evidence that supports the theory of evolution.\n\n1. Vestigial structures\n\nOne example of a vestigial structure in humans is the appendix. It has no function. Removing it is harmful only in so far as any surgery is associated with certain risks (so I wouldn't have it removed just for fun, but it's because of the surgery not the absence of the appendix). An appendix is found in several mammals. In humans it is small and has no known function. In rabbits and many other herbivores it is large and is used in the digestion of cellulose.\n\nAnother example of a vestigial structure is the hipbones of snakes. Snakes evolved from quadrupeds, and some species still retain not on pelvises, but tiny protrusions of bone in a location that corresponds to the location of the legs in other quadrupeds.\n\n2. Microevolution can be observed in both a controlled laboratory setting and in nature.\n\nCreationists will tell you that microevolution does not prove macroevolution.  This is true.
252845
evolution is the constant change in physiology a life form undergoes to remain adapted to its environment. Its hard not to believe in evolution. What is hard to belive is that God created all species in their current state and doesnt change them. I believe thats just the bibles answer because it was written before evolution was known.
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.
1114506
I would think that things gradually evolved over time.  There must have been enough "almost" butterflies to pro-create with the butterfly to have offspring.  So I feel it would be like being in the current of the stream and the stream would have kept pushing forward maybe a little different but in the same general direction.  Just a guess..  Good question.
312318
NatBoCheck: Well for starters even creationists believe in microevolution, but then you probably don't know what that is.\n\nGive me a few mins...\n\n"The process of evolution can be summarized in three sentences: Genes mutate. [gene: a hereditary unit] Individuals are selected. Populations evolve."\n\n"The mechanisms of evolution are mutation, natural selection, genetic drift, recombination and gene flow."\n\nMutation\n\nThe cellular machinery that copies DNA sometimes makes mistakes. These mistakes alter the sequence of a gene. This is called a mutation. There are many kinds of mutations. A point mutation is a mutation in which one "letter" of the genetic code is changed to another. Lengths of DNA can also be deleted or inserted in a gene; these are also mutations. Finally, genes or parts of genes can become inverted or duplicated. Typical rates of mutation are between 10-10 and 10-12 mutations per base pair of DNA per generation. \n\nNatural Selection\n\nSome types of organisms within a population leave more offspring than others. Over time, the frequency of the more prolific type will increase. The difference in reproductive capability is called natural selection. Natural selection is the only mechanism of adaptive evolution; it is defined as differential reproductive success of pre- existing classes of genetic variants in the gene pool.\n\nThe most common action of natural selection is to remove unfit variants as they arise via mutation. [natural selection: differential reproductive success of genotypes] In other words, natural selection usually prevents new alleles from increasing in frequency. This led a famous evolutionist, George Williams, to say "Evolution proceeds in spite of natural selection."\n\nNatural selection can maintain or deplete genetic variation depending on how it acts.\n\nGenetic Drift\n\nAllele frequencies can change due to chance alone. This is called genetic drift. Drift is a binomial sampling error of the gene pool. What this means is, the alleles that form the next generation's gene pool are a sample of the alleles from the current generation. When sampled from a population, the frequency of alleles differs slightly due to chance alone.\n\nAlleles can increase or decrease in frequency due to drift. The average expected change in allele frequency is zero, since increasing or decreasing in frequency is equally probable. A small percentage of alleles may continually change frequency in a single direction for several generations just as flipping a fair coin may, on occasion, result in a string of heads or tails. A very few new mutant alleles can drift to fixation in this manner.\n\nRecombination\n\nEach chromosome in our sperm or egg cells is a mixture of genes from our mother and our father. Recombination can be thought of as gene shuffling. Most organisms have linear chromosomes and their genes lie at specific location (loci) along them. Bacteria have circular chromosomes. In most sexually reproducing organisms, there are two of each chromosome type in every cell. For instance in humans, every chromosome is paired, one inherited from the mother, the other inherited from the father. When an organism produces gametes, the gametes end up with only one of each chromosome per cell. Haploid gametes are produced from diploid cells by a process called meiosis.\n\nIn meiosis, homologous chromosomes line up. The DNA of the chromosome is broken on both chromosomes in several places and rejoined with the other strand. Later, the two homologous chromosomes are split into two separate cells that divide and become gametes. But, because of recombination, both of the chromosomes are a mix of alleles from the mother and father.\n\nRecombination creates new combinations of alleles. Alleles that arose at different times and different places can be brought together. Recombination can occur not only between genes, but within genes as well. Recombination within a gene can fo
1134801
Relationship to other primates had been suspected for years before Darwin   (1840's)-- simple observation.  Now with the deciphering of the geome for both chimps, and humans, relationship has been proved beyond a shadow of a doubt.  We are all so similar even back to fish ---a central body with 5 protrusions -- head and 4 limbs.  I don't know it all, lady, but taught science and math for years, read Discover Magazine, Scientific American, and watch the Science channel.   Fascinating.... Evolution is no longer a theory, but a fact, a lovely fact.  Our medical research on rats, dogs, and other critters would be worthless if evolution were not..   Helpful?  The question is toooo complicated to fully explain.  But you can start by reading scientific journals....   Good luck  Life is a life-long learning process.....  and god has nothing to do with it.  Critters survived, and evolved.  If a gene were detrimental, the critter carrying it didn't live long enough to procreate.  It the mutated gene was beneficial, it aided in that critter to live long enough to reproduce.  Lots of evolution is even occuring today.  Google things like Darwin's Finches, pigmy elephants, and of course dinasaurs.  \n\nOne quick interesting thing about moths in England to illustrate evolution:  In the early 1600's, before the Industrial Revolution began and coal producing smoke was a fact of life, a particular moth was mostly white, and blended into the tree bark on which it laid its eggs. The tree bark was white. Occasionally a grey-black one was hatched, but never lived very long -- birds got it.  As the Industrial Revolution took off in England, producing black soot, that black soot began to cover the trees' bark.  In less than 150 years, the white variety was gone, and there existed only the darker mutant.  Beginning in 1950 when England passed anti air pollution laws, those trees began loosing the soot off of the tree bark.  Yup, you guessed it..... the white variant is now dominant........ evolution in action  ,,,,,Helpful????
1116290
DNA changes over a long period of time by different factors such as the temperature. For example, During the ice age, the organisms have tough skin, heavy fur to keep their body temperature warm. Then the earth warmed up so the these organisms no longer need the heavy fur to keep warm. Their children's children began to evolve to have less fur in order to not die of heat. The organism changes when its surroundings/environment change. Evolution is needed for the organisms to adapt and survive to the current living conditions presented upon them.
60008
Evolutionary processes can be of two types with respect to the pattern that can be seen. \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 happens in paleontological research and the decision to separate one from the other is ultimately arbitrary. \nCladogenetic (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. Our 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.\nA simple Google search will lead you to data from primate evolution research
1135377
You have to look at evolution as a series of slight beneficial changes that are passed down through generations.  The steps from single to double circ are unknown to me, but it is more than a single big jump.
522543
There is an enormous amount of evidence supporting evolution, and none I have seen disputing it at all- There are gaps in the evidence, but there is no evidence directly *against* the theory.  Originally it was thought that evolution happened in a slow, steady, manner-but fossil evidence mounted that disputed that view, and thus the theory was refined, so that now we know it generally occurs more rapidly when there is major climactic change, leaving different environments, creating new ones, killing off of existing species which creates empty niches for new animals to fill.  Most arguments against evolution depend on areas where there is lack of evidence, not on evidence that disputes the theory.  \nThe first evidence was Darwin's observations that birds adapted genetically to different environments, a process that is, in fact, slow and steady.\nThen the geological and physical evidence that the Earth was actually billions, not thousands, of years old meant that there was plenty of time for evolution.\nThen the morphilogical evidence of relatedness.\nThis theory also explained the many vestigial structures found in animals, such as the tiny hipbones in snakes\nIt was well documented and accepted by the early 1900's-THis theory predicted that there would be a close correlation of genetic patterns with morphology, and predicted that there would be vestigial genes in animals.  It also predicted that all forms of life would share certain genes, and that closely related species would have closely related, but slightly different, genes.  All of these predictions were shown to be true.\nEvolution also predicted that structure such as wings would have evolved at some point with a different function, since evolutionary mutations that are beneficial (less than 1 in 100,000) would tend to make small changes, and one could not expect a lizard to bear baby lizards with full-blown wings.  THus, the structures that become wings would be expected to have had some other function, and eventually evolved into wings.  For many structures, such as wings and eyes, these early purposes have been determined.\nRapid evolution, especially under conditions of stress, is seen in bacteria and other one-celled animals.  Because the theory states that it would require thousands of generations to observe evolution in action, only bacteria and other very rapidly dividing organisms can be tested for evolutionary changes that we can actually see.\nThus, the theory effectively explains animal and plant diversity, the predictions that the theory made were shown to be true, the fossil, genetic, and morphological data from the past support the theory, and it has been demonstrated to occur in the only animals that it could be demonstrated in, bacteria.\nFor a theory about how things have occurred over the last few billion years, when we cannot actually "see" it occuring, when it has happened over a span of time far beyond our historical records, this is an overwhelming and nearly indisputable amount of evidence.\n\nThe theory does not predict that animals will become "better" over time, just that any genetic mutation which increase the viability and number of offspring will tend to change the species- Remember, the theory of evolution is only one of biochemistry, genetics, and environmental interactions- It is not a philosophy, religion, or value system- Evolution does not make value judgements, does not plan or think or even care- it is merely a physical process like a rock falling down a hill.
166140
Evolution is still happening today, so it is observable. However, it takes many generations for any adaptation to become part of the genetic code of a species, and therefore, only in a great many generations will there be any concrete proof. Scientists do not claim to have proved it, at least, none of the scientists I've consulted on this matter. They say there is a lot of evidence to substantiate the theory of evolution and none to disprove it, which I believe to be true. Because of this, it's a theory that has ceased to be contested. However, it is still a theory, with lots of evidence in it's favor but no proof.
411785
Genetic information is increased by mutation of the genetic material inside an organism. Natural selection simply removes the less advantageous mutations. An increase is not necessarily an improvement but is simply an increase.\n\nDo not think of one current species becoming another, instead think about one common ancestor to both and then how the mutations occurred over million of years and generations to present very different animals.\n\nCertainly, there is a consciousness that can be applied to the selection. Genocide is a good example of somebody thinking they can direct the development of a whole species. Surely the Final Solution is evidence that humans can think in this way. It doesn't mean we should but it proves that we can.
748748
Here's a little known fact - the theory of natural selection - very few on YA can describe it correctly yet it's very simple:\nThere are just 3 assumptions:\n\n1. Individual members of a species are not always exactly alike. A population of similar organisms displays variability.\n\n2. Organisms possess some mechanism by which offspring tend to be like their parents. That is, individual traits are heritable.\n\n3. Totally unrestricted breeding doesn't happen. No population can reproduce forever without limit. So clearly there must be some force at work to reduce populations.\n\nFrom these assumptions Darwin concluded the theory of natural selection - some of the variations between individuals are inherited by their offspring, and, in a world where not everyone can survive, some of these inherited characteristics give some individuals a better chance of survival.
226
Evolution is ever-present as always. You could argue it's rate is a function of environment change. So to answer what's driving human evolution you need to look at the human environment as part of the equation. Extreme evolution happens when an organism's environment changes and it cannot escape it. As a previous post mentioned, humans now have the ability to easily move around the world and escape a 'bad' environment. So evolution may indeed have slowed, but it is not dead. Some cataclysmic change affecting the whole planet, if it doesn't kill the species completely, will certainly speed up the evolutionary process when you compare the human race a few generations either side of said event.\n\nGiven that evolution is the result of genetic mutation/favoritism during sexual reproduction are we seeing those more desirable for sex setting the evolutionary path while environment change is minimized by our ability to control it or escape it?\n\nIs average height an example of this? It would certainly seem that humans are growing taller on average, and what western (cultural bias) woman does not want a tall mate for example. It should be noted however that who we think is desirable for sex is very culturally dependent and may not lead to the best long-term (breeding) prospects for an individual conceived to those parents.