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Evolution
The scientific theory according to which populations change gradually through a process of natural selection.
5,264 Questions
Could anyone give me facts about evolution?
Unsure why this is in the religious section; its a scientific matter.
Facts?
Firstly evolution IS a fact. Why is it called the theoryof evolution? The same reason its called the theory of gravity. Scientific nomenclature, a theory is a set of statements which explain the physical world. And can always be updated/upgraded/improved upon.
The fossil record, sampled millions of times from 1000s of sites all over the world, has never contradicted itself. Animals and plants appear at certain times (i.e. become visible in certain layers) and never before (never in deeper,older layers). This shows how species originate at set times by diverging from ancestor species.
Next theres radio-dating. No, its not an inadvisable pastime for lonely people, its a phenomenally powerful scientific technique which allows us to calculate the ages of pretty much anything.
Heres how it works. When created through geological processes, all rocks contain trace amounts of unstable atoms. These atoms spontaneously break down over time, releasing radiation and changing into different elements. A few of these breakdown products, the newly created type of atoms, take a long long time to break down further. Because we know
1) how much of each element is present in these rocks when theyre created
and
2) the half life of all types of radioactive atoms, that is, the time it takes for half the original amount of atoms to break down into something else,
we can simply find out how much of a certain element is left and multiply back up until we reach the original level.
Example
Lets say we know that rock A when created from clay under an ocean (for example) has 10g per kg of Skitterium in it and we know that skitterium breaks down such that theres only half left after 50 million years
we measure how much is in the rock we find our fossil in and we find theres only 2.5g per kg
2.5 x 2 = 5 and x 2 again = 10 so because each "x2" takes 50 milllion years, we can say that the rock, and hence the fossil is 100 million years old.
So fossils in a certain rock layer can thus be confidently regarded as being a certain, specific age, and we can say "this species first appears here, in rocks which are 100 million years old".
Molecular biology is capable of even more accurate predicitons - it can show us which species' are more closely and more distantly related to one another.
The rate at which certain proteins change (mutate) are very very reliable indicators of how long ago the body containing the protein diverged from its ancestors - e.g. a horse and a pig have the same protein doing the same thing in their cells but each version of this protein is slightly different. Comparing changes in many different proteins in two species yields an estimate of how closely related the species are - how long ago these two species split from the original ancestor species.
Take us and chimpanzees. Molecular biologists have shown (using the haemoglobin proteins initially) that not only are we closest to chimps evolutionarily (i.e. chimps are the species we most recently share a common ancestor with), chimps are closer to US then they are to gorillas.
And we can do this for every species alive, including microorganisms, right they way back to around 3.5 billion years ago.
Folow this back up the tree of life and one conclusion swiftly becomes clear.
All life came from one original organism.
Which mulitplied. Again and again. And once there were millions then there was competition and then natural selection (only the fittest survive) could begin to forge differences. Better at eating then your fellows? You tend to breed more and then replace the population. Find yourself in a strange new environment? Then the individuals most suited to it will survive. And if isolated there for any reason, then you have the conditions for what are now effectiverly two separate groups of organisms to go their separate ways. Over time each group changes to suit its environment and becomes less and less like their old ancestral population. When talking about animals which reproduce sexually, the stage is reached where the two populations cannot interbreed. Two species now exist where once there was one.
As if the fossil record, molecular biology, current biology and taxonomy werent enough (they are) we have also seen evolution in action, both in terms of the emergence of drug resistant strains of bacteria/plants/insects but here is something truly amazing:
http://www.newscientist.com/article/dn14094-bacteria-make-major-evolutionary-shift-in-the-lab.HTML
this article describes the amazing experiment done by Lensky and his group in the USA, where he simply bred E.coli Bacteria, generation after generation after generation for 20 odd years and simply kept an eye on them.
What happened?
Well its almost a crime to cut such ingenous and elegant experiments down to the following summary but here we go:
they found that, over time, in a fixed environment E.coli bacteria evolved the ability to metabolise citrate - something that normal E.Coli cannot even begin to do.
And in order to metabolise citrate there were at least 3 necessary, sequential mutations required. In other words, the bacteria had to mutate at least 3 different times in a row in order to do this. And they did. And replaced all the "ancestral", non citrate eating bacteria.
This kind of evolutionary change is almost possible to see in most organisms as the number of generations needed for changes to occur means that, often, millions of years need to pass. Too long for most grant funding bodies...
So. To summarise:
1) New types of animals and plants appear in the fossil record suddenly and always in the same order. This shows that species appear over time and have not "always been there"
2) Using radio-dating we can prove the ages of the rocks the fossils lie within. Thus we can measure how long ago species diverged from common ancestor - this is how we know the age of the dinosaurs was over 150 million years ago, because that's how old the rocks containg their remains are.
3) By looking at the mutation rate among and between species, we can show which species are closely related and which arent and construct a "tree of life" - we can begin to play events backward. If we do this we see that all species converge on a single ancestor some 3.5 billion years ago
4) By comparing the results we get from the above 3 methods we should reach a consensus for each species. We do. All three separate methods agree with one another. This is enormously powerful evidence that evolution is a fact.
5) We have directly observed bacterial evolution.
Please please check these facts for yourself - read any journal, any textbook written in the last 10 years.
If you don't "believe" in evolution its like not "believing" in gravity:
Its still true.
Which is the best evolution of gloom?
I think it may be Vileplume becos it is a poison type so it can poison its enemy's and so and so your enemy's hp is down for the cont
Does evolution continue to occur in organisms today?
Absolutely. Evolution isn't an historical process; it is on-going as long as there is life.
What does adaptation have to do with homologous structures?
Homology is the occurrence of similar structures in different organisms because they are descended from a common ancestor by the process of evolution. The same structure can be adapted for different functions in different organisms, but still reveal the same underlying, homologous structure. So organs which appear to be very different in different organisms can in fact contain the same structures ie homologous structures. A famous example is the pentadactyl limb in vertebrates. This is adapted for many different forms of locomotion but still contains the same basic pattern of bones. For example, the human arm, bird wing, bat wing, whale flipper and horse leg are adapted for different functions but have the same internal structure ie a single upper limb bone, two lower limb bones, several wrist/ankle bones and hand/foot bones with five digits (fingers/toes). So, adaptation can lead to the modification of homologous structures in the descendents of a common ancestor. For more information see: http://www.zoology.ubc.ca/~bio336/Bio336/Lectures/Lecture5/Overheads.html http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_09 http://evolution.berkeley.edu/evolibrary/article/similarity_hs_01 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Taxonomy.html
What percentage are humans fish?
Odd question.
The last common ancestor of humans and fish probably lived about 300 million years ago, but we share quite a number of genes with fish though I do not know the exact percentage. Many genes are highly conserved and only controlled in different ways to make different organisms.
How many missing links are there in evolution?
First of all, let me explain why the term 'missing link' is inaccurate and misleading. It suggests that there is something wanting from the fossil record, where it really isn't. Some intermediates have been projected but have not yet been found; however, hundreds of transistional fossils have been found without having been projected, nevertheless confirming phylogenies established on the basis of morphology alone. And, of course, some intermediates have been specifically projected and subsequently found.
The definition of 'transitional fossil' is any form that is morphologically intermediate between the basal form of a clade, and a more derived form within that clade. Since the number of morphological intermediates between one ancestral form and its remote descendants is potentially as high as the number of generations between these two forms, it's virtually impossible to project how many intermediate forms we should expect to find even in a single lineage. Moreover, evolution is not a linear or well-ordered process, but a chaotic one, which complicates such deliberations.
In the end, the question itself is irrelevant to our determinations, since however many transitional fossils remain missing, every fossil that we do find confirms common descent and helps clarify various phylogenies.
Why do some biologists say that fitness is measured in grandchildren?
In biology, fitness is a measure of the ability to produce fertile offspring. In other words, the ability to produce children that can produce grandchildren. So the number of grandchildren would be a more appropriate measure of fitness than the number of children.
Evolution occurs because biological organisms reproduce with variation, and variants reproduce at different rates.
Genetic variation is the result of genetic mechanisms such as reproductive recombination and spontaneous mutation. These mechanisms ensure that each offspring is a unique combination of alleles. Alleles are "rival" variants of genes with a specific "function". For many genes, having one allele rather than another will result in some difference in expression, resulting in turn in a difference in phenotype, which might result in a behavioural difference, a difference in appearance, or a difference in metabolic rate, for instance.
It stands to reason then, that it is possible that different variants react to circumstances differently. A variant with slightly longer intestines might find it easier to process certain foods, opening up a new niche for itself and its offspring. A variant with slightly longer fur might find it easier to venture into colder areas to gather food, again giving it and its offspring access to a new niche.
If the circumstances are thus that a particular trait or combination of traits makes it likely that a variant has a higher average number of offspring than its rival variants, then this will result in an increase of the number of alleles representing this variation in the next generation. This trend can, if these circumstances remain the same, persist until the great majority of the population possesses these successful traits.
Together, the emergence of new traits through reproductive variation, the spreading of successful traits and the decline of less successful traits through reproductive differential success, are called evolution, and the mechanisms behind these trends are the reason that evolution happens.
True, Darwin did realize that the observed variations among individuals within a population were caused by selective breeding.
Although he did do a lot of great stuff. He wrote a book called The Origin of Species.
You should check it out if you would like to find out the stuff that he did and what he found out about evolution. Either that or rent a book from a library about evolution.
Why are some living things almost similar in colour to their habitat?
Over time, the organisms that are successful in a determined habitat have traits that increase their chances of survival (adaptations). One of these adaptations is camouflage. When there is a mutation in the population that alters the color of the organism, the result can be negative and the organism is easier to see and gets eaten or it can be successful and helps the organism blend in and increases the chances for survival.
In WHAT YEAR was the first person on earth?
Look at a clear sky at sunset. Notice the difference between the darker sky on one side and the bright sunset at the other. If you can't tell exactly at what point in the sky it goes from purple to pink, then you will know why no-one can answer your question.
What must individuals with a trait do in order for evolution to occur in the population?
The trait must be in the germ line, it mist be passed on t progeny who thrive well enough to pass it on in an amplified manner, it must be beneficial, that is confer reproductive advantage and then the frequency of this allele must come to fixation in the populations gene pool. Then evolution, the change in allele frequency over time in a population of organisms has occurred.
The stomach is not a recent evolutionary adaption. The first creatures to have stomachs developed billions of years ago in the early oceans. These were simple-celled organisms with specialized organelles that broke down the food absorbed from the environment and expelled the waste. (These are comparable to the human stomach and digestive track, just much simpler.) As these organisms became more and more complex through the forces of natural selection, so did their digestive systems. They eventually split and gave rise to aquatic insects (crustaceans), fish, octopi, mollusks, etc. The first creature with a stomach to walk on land was the aquatic insect, the ancestor of today's insects. Then came fish, led by the lobe-fin, which also had rudimentary lungs and limbs capable of bearing weight. Terrestrial fish gave way to amphibians, which gave way to reptiles, which gave way to birds and mammals. Mammals are vertebrates like cows, dogs, lions, horses, bears, and apes. Humans are descended from a line of proto-apes. Our modern stomach is therefore the result of billions of years of evolution.
There are many overall similarities between the stomachs of various animals. This points to common ancestry. For more on the similarities (and differences) between fish, amphibian, and mammalian stomachs, see the paper linked below.
What do people think of Kent Hovind?
Wikianswers isn't really intended to be an opinion service; however if you look at the Wikipedia article on Hovind, he is criticised by "creationists" for presenting obviously invalid arguments and thus making their position look weaker, evolutionary scientists who have debated Hovind are surprised by his ignorance of evolution.
The theory of evolution states that most living organisms share common ancestry. Charles Darwin proposed this theory 150 years ago to account for the remarkable diversity of life around the globe, and to explain apparent successions of fossils.
Since Darwin's time the theory of evolution has been modified to incorporate discoveries in genetics. We now know the source of the mutations that create change, for example. We have also learned a great deal about earlier stages of life. Multicellular organisms clearly originated in a marine environment. We have fossils of fish that predate any fossils of land plants or animals. Given that fact, evolution would predict the earliest terrestrial vertebrates should be amphibians.
It turns out this is what we find. Fossils of amphibious creatures like ichthyostega, eusthenopteron, acanthostega, and eogyrinus all bear remarkable resemblance to sarcopterygian lungfish of that era. One telling find was discovered by paleonotologists who predicted (on the basis of evolutionary theory) that there should be a creature with particular features in specific strata. When they searched that strata they found Tiktaalik roseae.
There are hundreds of scholarly papers published in peer reviewed journals on the subject of biological evolution each and every year, and this has been the case for decades. Research into this subject is ongoing and pervasive--it is of keen interest in numerous prestigious universities around the world. Essentially no research has been conducted that casts any serious or substantial doubt on the accuracy of Darwin's theory. On that basis I am led to the conclusion the theory is essentially correct.
Where are penguins originated from?
The ancestors of the earliest penguins lived around the time of the Cretaceous-Paleogene extinction (~65 million years ago) event somewhere in the general area of what is now southern New Zealand and Byrd Land, Antarctica. It appears likely that at this time they still had the ability to fly, but this cannot be confirmed from the available fossils.
What evidence shows that the kingdom Protista have a common ancestor with plants?
Many protista contain chloroplasts.
Who aired Ichigo Momomiya's Evolution?
Yes. Ichigo Momomiya's Evolution in 2008 film is released and Little Mermaid - Ariel's Beginning is replace.
Which of these was not derived from an ancestral alpha proteobacterium?
Answer Choices:
A) mitosome
B) kinetoplast
C) chloroplast
D) hydrogenosome
E) mitochondrion
Answer:C) chloroplast
Explanation:
Chloroplasts are not related to all the other choices. Mitochondria, kinetoplasts, mitosomes, and hydrogenosomes are similar in that they both deal with cellular respiration, regardless of whether it is aerobic or anaerobic. On the other hand, chloroplasts deal with photosynthesis, a process which is the complete opposite of cellular respiration.
the production of a new genome through the transfer of part of the genome of one organism to another organism.
What is the main contribution of neo darwinians to theory of darwinism?
By linking genetics and systematic biology in one synthesis the neo-darwinians showed, mathematically, that natural selection could account for adaptive change in organisms and the evolution of populations over time. This was the beginning of population genetics.
the grey man theory is how much i love sex and penis
How do evolutionary scientists answer the Fibonacci argument for intelligent design?
The Fibonacci argument is usually presented by those who have a misinformed understanding of how evolution works. They will express that, because evolution is random it should be impossible to find these in nature sequences in nature. However evolution is not random.
Mutations are random but natural selection is quite the opposite.
