0
Evolution
The scientific theory according to which populations change gradually through a process of natural selection.
5,264 Questions
Evolution is driven by natural selection, genetic mutation, genetic drift, and gene flow. These processes act on the variation within a population, leading to changes in traits over generations. Ultimately, evolution is a result of organisms adapting to their environments to increase their chances of survival and reproduction.
Is speciation an example of miro-evolution in organisms?
Yes, speciation is an example of micro-evolution in organisms. It refers to the process by which distinct species evolve from a common ancestor through the accumulation of genetic differences over time. This gradual divergence can lead to the formation of new species that are reproductively isolated from one another.
Evolution can be just a noun derived from the verb 'to evolve'. It means to develop, to change...
There is an evolution of everything in this sense; evolution of language, evolution of one's knowledge of a book's characters as one progresses through a book, evolution of a garden as one plants more things, evolution of this answer as I progress through writing it, evolution of the sort of questions asked on WikiAnswers...
However, the questioner most probably desires an explanation of biological evolution. This is known as the Theory of Evolution and Darwinism. It was made famous by its hypothesiser Charles Darwin. Since its hypothesis state it is now the greatest underlying theory of biology.
It explains, along with its mechanism of Natural Selection, how organisms change over time. Gene frequencies change in populations of eukaryotes, genes are shuffled at eukaryotic meiosis and prokaryote genomes change by mutation. All these mechanisms bring about phenotypic change. Change is inevitable with the, not 100% faithful replicators, nucleic acids enclosed within the outer membranes of organisms.
Change can be selected by Natural Selection. Not all phenotypes are suited to environments and those nonsuited are eliminated by Natural Selection and this further modifies gene frequencies in populations (in eukaryotes), giving more continuous scope for evolution.
Evolution is traced via comparative genetics and genomics, comparative anatomy, comparative biochemistry and the fossil record.
According to the Theory of Evolution, life started in the oceans. Bacteria like cells first appeared and eventually branched into myriads of other forms, prokaryotic and eukaryotic. Photosynthesis evolved and multicellularity evolved. Protists radiated, as did plants and animals. Plants took over the land as simple mosses and liverworts that were gametophyte-dominant. Gradually the gametophyte was reduced to a few cells in pollen grains of angiosperms and the sporophyte generation evolved fully dominant instead.
Animals evolved from simple nerve-less and heartless organisms as sponges, eventually giving rise to both radiate and bilateral animals and among the latter, diploblastic and triploblastic lineages. On-substrate movement brought about cephalisation and as a result directionality was procured.
From wormlike creatures with notochords (the larvae of urochordates), evolved fish and from lungfish and coelocanths evolved amphibians and from amphibians evolved reptiles and from reptiles evolved mammals and dinosaurs and from dinosaurs evolved birds. Among mammals, humans evolved from apes. It is incorrect to say that humans evolved from chimpanzees. Humans and chimpanzees evolved not FROM one another but WITH one another. Both arose from a common ancestor, a Pan-Homo common ancestor.
There are many arguments against evolution. These are often propounded by people of a number of religions, proponents of the pretending-to-be-unreligious Intelligent Design movement, people who do not understand evolution and have not been properly taught about it and, no doubt, people who pick up arguments against evolution from people who give them the idea that evolution is something to be against and the anti-evolution arguments themselves have scientific merit.
Evolution is a theory. Richard Dawkins wants to call it a fact. It is a fact. Dawkins proposes the word theorum for evolution. I like the phrase 'body of fact' or 'megafact' which is a word I now coin.
Evolution has much evidence to support it. But it is an origins-theory. It explains the origins of species. The realm of Bibles and religions came about before Darwin and his Theory of Evolution by Natural Selection and seemed to claim originofspecies-explanation as its own. Origins-explanations are dear to people simply by being origins-explanations. They are even dearer if they are ruled by a beloved omnipotent omniphilic religious entity such as a god.
Thus the ungodguided appearance of evolution offended those who knew the godguided creation stories. Since then, offended people have been, offendedly, ejaculating many arguments against evolution. Some stray into the scientific as opposed to religious realm, perhaps since the offendeds first noticed sciences inability to build explanation and scientific theory out of supernaturalism.
Arguments against evolution include:
The Bible says that God created life, and separately (in six days).
Evolution violates the second law of thermodynamics.
If humans evolved from apes, why are there still apes?
Life cannot evolve from 'pond-scum'.
There is not a single transitional form.
Earth is too young to support the theorised lengthy periods of evolution.
Evolution is 'just a theory'.
Evolution leads to atheism, immorality, suicide, misery..... Just look at atheists like Hitler.
Evolution is a religion as it must be 'believed' in.
To my knowledge, many religious people, fundamentalists who believe literally that everything was created in 6 days are so religious, so convicted that they won't even listen to scientists or even a more (to them) harmless passer-by who happens to have read something about evolution. They go near nothing that remotely challenges creationism or suggests a godlessness for the Universe.
They may be interested in science, but their knowledge can only be peripheral and basic as they (if they exclude evolution from consideration) often reject continental drift, old-earth geology (which is all of geology), abiogenesis, the existence of dinosaurs and other pre-Modern organisms and the big bang standard model of the origin of the Universe. Perhaps some even refuse to consider stellar processes such as nucleosynthesis. How can this lead to a full appreciation of what science has and can work out about the Universe. What sort of science-knowledge is this?
Richard Dawkins points out that denouncing of evolution may not come directly from thinking evolution is unlogical but from a moral-holding (god-ruled morals no doubt) opinion of 'ungodguidedness is immoral'. Still, science finds supernaturalism (as said above) untenable and so these offended fundamentalists, creationists or religionists have to attack evolution with science. All their anti-evolution arguments are untenable, useless and invalid. Is it their peripheral appreciation and knowledge of all of science that makes this so?
Below is an explanation of why all the arguments I listed above are invalid.
The Bible does say that God created all life. To a comparative religion studier, this would be referred to a creation myth. Science rejects God because he is undetectable and supernatural and needs faith to think he exists, possibly a concession that such an object does not exist on the part of the religious. Also, the lengthy time-periods of geology and the fossil record do not support a 6 day creation.
The violation of the second law of thermodynamics is not so. If biological processes that involved reproduction and growth and generation-progression violated this law then no organism would ever get beyond the zygote stage.
Humans did not evolve FROM today's apes, nor specifically from chimpanzees (closest relative to humans). Humans evolved WITH chimpanzees. Life evolves by common ancestry. There was a Chimpanzee-Human common ancestor and further back in time a Gorilla-Chimpanzee-Human common ancestor and further back in time an Orangutan-Gorilla-Chimpanzee-Human common ancestor. Humans evolved from a single twig of the ape branch of the tree of life. Evolution does not proceed as a complete transformation of one species into another (like all chimpanzees suddenly becoming humans or giving birth to humans) leaving a disappearance of the 'parent' species behind.
'Pond-scum' or Kent Hovind's disparaging 'lightening on mud' or (with regards to the big bang) 'all the dirt in the Universe) are statements of absolute unscientificness. There is no such thing as scum or dirt in science. Science talks about elements and gives them names (such as oxygen and carbon and nitrogen and silicon). Life is formed from elements. Cells are formed from elements. Life can evolve once a nucleic acid is enclosed/delimited/contained in a membrane. That is all that needed to happen.
There are indeed transitional forms like Archaeopteryx. There are lineages alive today that give clues as to transitions, like hoatzins, platypuses, lungfish and coelocanths, hippopotamuses, Australopithecus and welwitschias (which give clues as to the origins of angiosperms).
Earth-age is a matter of geology. But evolution theory needs it since evolutionary processes take a long time. Earth is not 6000 years old as the Bible-literalists claim. Earth is 4 600 million years old. The uranium dating mechanism that was used to measure this is no doubt inaccurate by a few hundred million years. This is about 1% of the total magnitude of the age and is thus negligable. Earth is very very old. The way of measuring Earth as 6000 years old was done by examining ages of humans in the Old Testament. This presumes that humans have existed for the entireness of Earth's history. However to measure something's age it is better to measure the age of what that something is made of (rock in Earth's case). One cannot measure something peripheral (like human-age, humans just being on the surface). If measuring age were done like this, the age of a wad of cheese would be measured by the age of the mould growing on that cheese or a person's age would be measured by measuring the length of time they'd been wearing that morning's shirt.
The 'just a theory' argument shows lack of understanding of 'theory'. Theories are all-incorporating explanations that tie together many facts. Hypotheses are promoted to theories only when confirmed by convincing evidence. It is appropriate to say 'just a hypothesis' of something of course. And of course that would be inappropriate for evolution, which is a theory and not a hypothesis. Hypothesis is almost synonymous with guess. Theory is almost synonymous with fact.
Evolution suggests ungodguidedness perhaps. I admit that religion exists as a comfort for humans in a frightening universe. However, if evolution is the truth we must not shy away from it obviously. Then we have a true explanation of the biological world's diversity! To think there is a god is faith and so regardless of what science you accept god can still be imagined for comfort. To the thinking person and the common sensical person, atheism may well abound in their thoughts and knowledge of the universe anyway, regardless of Darwin's theory of evolution.
Is evolution depressing? Mindless mutations locked into existence nonrandomly by selection or eliminated? Look at the beauty of life's biodiversity. One must not fail in the imagination just because a process is mindless. Evolution has great power. Theodosius Dobzhansky said 'Nothing in evolution makes sense except in the light of evolution'. The 'Origin of Species' has the words 'Out of the war of Nature' and out of this emerges Darwin's evolved 'forms most beautiful'. There is constant action and colour and wonder in the world of life, of animals, plants, genetics, ecosystems and the beautiful biosphere as a whole. Why would anyone be sad about that. All life has a life-force just like you, selected by Natural Selection. Can all life appreciate life as much as we do?
Does evolution (as the Theory of Evolution) lead to Hitler-persons and their vicious killings of fellow humans? I'm sure many people will agree that Hitler was a horrible git (we could always be ruder and about Hitler is the place to be so) no matter how you slice it. Hitler's horribleness surely has nothing to do with evolution. Evolution is an innocent description of life-adaptation and change and diversification. If Hitler produced atrocities after having heard of evolution, it must be remembered that Hitler was horrible and ghastly no matter how you slice it. Maybe the Hitler argument is simply used by serious anti-evolutionists trying to incite moral outrage. Notice that it is not against the mechanisms of gene frequencies and mutation and Natural Selection and species diversification. It is just against a theory which says nothing of God and morality and Bible-said statements and thus regards it as immoral/ungodly.
Finally, evolution is not a religion. It is a science. When it is said 'Scientists BELIEVE that Earth is 4 600 million years old' or 'Scientists believe that endosymbiosis took place' or 'It is believed that all life has a common ancestor', that word BELIEVED means 'thought sensible and logical' and 'is thought a good account of what occurs in reality', 'is thought a good description of the world'. It is not religious at all as it is based on evidence and logic and common sense and knowledge and not faith.
All arguments against evolution arise from faith-based contempt for nonfaithful, nonreligious science-explanation. All of them are completely invalid.
Evolution remains a perfect fully-supported theory, which explains the origins and diversifications of 'Darwin's forms most beautiful', the beauty of life....
Are all organisms living things?
Yes
**G1N4**
I thought some living things are not organisms, because they are not free living.
What role does DNA play in mutation natural selection and sexual selection?
DNA is fundamental to our understanding of evolution. DNA does not change and so showing evolution over time, but it is merely evidence of an evolutionary link between certain species. For example, DNA is extremely similar between humans and apes. Darwin and his theory suggested that modern humans developed from apes through evolution. The fact that human and ape DNA is about 97.5% the same shows a possible link between our possible ancestors and humans.
Because DNA provides much of the information about ourselves. DNA also can give clues about a person's intelligence. Intelligence seems to be more important than brute strength from an evolutionary standpoint, because we humans used our phenomenal smarts to outwit other stronger species to get food.
Mutation is an interesting topic because it can be for the better or for the worse. Mutations are caused by an error or misprint in the DNA as the DNA is being 'printed out' by enzymes. In other words, a mutation is simply a mistake in our DNA. Humans have about an average of 50 mutations in our DNA, and generally few or none are harmful.
A possible mutation that we humans have is dairy tolerance from cows and sheep, goats, even CAMELS after we reach the age of three.
The trait for blue eyes is actually a mutation that stems from one person almost 10,000 years ago and it and the lack of skin pigment that goes with it allowed us to live in areas with low sunlight.
Each organism gets chromosomes from both their mother and father, and the number obviously varies between species. Humans, for instance, have 46 chromosomes, which consist of one set of 23 from each parent. These 23 pairs of chromosomes are contained within the nucleus of our cells.
DNA replicates itself by unraveling the double helix and making copies of the original strands through the aid of enzymes.
Chromosomes are prone to 4 kinds of mutations: deletion, duplication, inversion, and translocation. Deletion happens when a section is not replicated. Inversion happens when a section flips itself inward (i.e. head over heels) from its original position. Duplication happens when a section is doubled. Translocation happens when the section of one chromosome is switched with a section from another chromosome. This happens because chromosomes fold over each other during replication. This can sometimes result in the complete fusion of separate chromosomes (this is why humans have 46 and our relatives the chimps have 48).
Humans and other organisms commonly have thousands of non-harmful mutations in their genes and chromosomes. However, these mutations can sometimes have negative or beneficial effects. A negative example would be the way base pair substitution in the hemoglobin gene can lead to Sickle-Cell Anemia. This nasty disease causes red blood cells to take on a sickle shape, which can lead to complications like stroke and kidney failure. The disease plagues many African-Americans. Oddly enough, SCE is also a beneficial example. The gene mutation that causes SCE is believed to have arisen in Africa where it provides people with a resistance to Malaria.
The primary function of all life is to pass on genes to the next generation. Those who have more children are considered to be the fittest in their environment. If a random mutation provides an organism with a survival advantage, they will be able to pass on more genes than their peers.
A survival advantage could be a fish being born with a bony segment in its fins that would allow it to travel briefly between shrinking water sources during a time of drought or to catch prey on the shoreline during aquatic food shortages.
The fish would naturally survive longer than those born without this mutation and pass on more genes. This means the environment would determine the mutation to be beneficial. This is known as Natural Selection.
Natural Selection is the mechanism that drives evolution. This is because random mutations can accumulate over periods of deep time to produce large scale changes in the morphology of a species until they become a new species altogether.
The fish I described above is actually an ancient species known as the Lobed-Fin, which first waddled the earth some 400 million years ago. Natural selection eventually caused the descendants of this fish to take on more adaptations better suited for life on land, including lungs (adapted air bladders) and jointed limbs. Groups split off during the following ages to give rise to the amphibians, reptiles, birds, and mammals (including humans). All of this diversity came from only small incremental changes over millions of years.
Sexual Selection is a type of Natural Selection. But instead of the environment determining whether a trait is beneficial, it is the female of a species that determines the benefit.
Females tend to choose mating partners based on physical attributes that signal the resulting offspring will survive to pass on their genes.
Female Gorillas, for example, are half the size of males because they select powerful mating partners. Males battle each other for mating rights with the females. Males who are the biggest and the strongest stand a better chance of passing on their genes and producing offspring with the same traits.
This explains why gorillas are so much larger than the other great apes. Another example is the tail of a male Peacock. Females select males with larger, more ornate tails to mate with.
The tails are actually quite heavy and create a risk to the male because it costs extra energy to maintain such a secondary sexual characteristic not to mention the fact that the extra weight would slow escape from a predator. But the size and color of the tail signals to the female that the male is strong with good genes. These characteristics were initially conceived through mutation and then built upon through sexual selection.
Personally, as far as I am aware no evolutionary scientist holds this position. While individual evolutionary changes do occur in a shorter timeframe and some of these have been observed, they do not assert that the total evolution of life on earth occurred in so short a timeframe.
If they did assert such this would be rather close to the young-earth creationist position and would also involve a massive amount of change in what is for them a very short time indeed.
Rather, evolutionary scientists understand the earth to be around 4.54 billion years old and the universe to be much older. The age of the earth is thus a key point of contention between the evolutionary scientists and young-earth creationists, the two positions being poles apart.
FAD, or Flavin Adenine Dinucleotide, can be converted into FADH2 through a reduction reaction that involves the addition of two electrons and two protons. This conversion allows FAD to act as a cofactor in various enzymatic reactions that involve the transfer of electrons.
Why do animals and plants move?
Animals move to find food, water, shelter, mates, and to avoid predators. Plants move in response to environmental cues such as sunlight (for photosynthesis), gravity (for root growth), and mechanical stimuli (e.g. touch-sensitive plants).
How did the two sexes emerge from one?
The emergence of two sexes likely occurred through a process called sexual differentiation, where genetic and developmental mechanisms led to the evolution of distinct male and female reproductive systems in organisms. This differentiation provided advantages for reproduction, genetic diversity, and adaptation to changing environments, ultimately promoting the survival and diversity of species.
Is evolution still taught in schools?
Yes. Evolution is a fact and the theory of evolution by natural selection explains this fact.
Creationism and Intelligent Design are always rejected as science in US courts. It gives rise to a constitutional issue.
Evolutionary theory is the backbone of biology and you are not specifically educated in biology if you do not know this theory. And I would say you are not generally educated if you do not have exposure to this, one of the core theories of science.
How is adaptive radiation different from divergent evolution?
I think it is Puncuated Equilibrium. I am not sure.
No Punctuated Evolution is a period of stasis where no changes occur followed by sudden rapid change.
It is Divergent
How do modern scientists explain the changes within species that can lead to evolution?
Evolution is a slow, slow process which enacts itself over many generations. Species evolve to adapt to environments and to survive, which makes evolution the mechanism through which "survival of the fittest" succeeds as a natural order.
A couple of fads from 1971 are disco music, and cassette tapes. Acupuncture also was a fad after President Nixon found it on a trip to China. Popular foods of 1971 were Hamburger Helper and Quiches.
Protein synthesis on the primordial Earth may have been catalyzed by RNA before the evolution of enzymes. This hypothesis, known as the RNA world hypothesis, suggests that RNA molecules could have functioned both as genetic material and as catalysts for biochemical reactions, including protein synthesis.
What is an evolutionary track?
An evolutionary track is a representation of the path taken by a population or species over time as it evolves. It typically shows changes in traits, genetic makeup, and adaptations in response to environmental pressures. By studying evolutionary tracks, scientists can better understand how species have evolved and diversified over millions of years.
There are countless examples of this type of evolution, but I will give you one; Humming birds and the elongated pouches of the flowers they eat from; If the flower already has a long pouch, and a bird who's diet is of nectar but doesn't have a long beak, birds with longer beaks will get to eat more, thus it will be healthier and get to pass it's genes on. While the flowers that don't attract as many humming birds (maybe they don't have sweeter nectar or a more attractive color) don't get polinated as much, and so they don't pass as many genes on than the ones who do.
What do the various rewards for proof of evolution demonstrate?
All the so-called rewards that I am aware of are offered by creationists, who have probably offerred amounts beyond their ability to pay - in one case, ten million lira. The fact that apparently enormous "rewards" are being offered only by people with strongly held views opposed to evolution demonstrates that this is a propaganda exercise, not a genuine quest for proof. What this also demonstrates is a belief that the public will believe anything if you appear to show confidence in your beliefs.
Take for example, the "reward" offered by Kent Hovind. The principal roadblock to claiming this reward is that you have to convince him and him alone of evolution, and he has already declared all scientific evidence to be false. He has not put any money in trust, nor appointed an independent panel of scientific experts to make the decision. So, it doesn't matter whether he has a quarter of a million pounds on offer: he is in the position of always declaring himself unconvinced.
If such reward had been offered by a science foundation on the basis of an independent arbitrator and fair rules, the reward would have been claimed long ago. The absence of rewards on offer from genuine science foundations, or even from uncommitted philanthropists eager to advance scientific inquiry, demonstrates the confidence that proof of evolution is no longer required.
For more information, please visit: http://christianity.answers.com/theology/the-story-of-creation
A landmark is an important place/monument/building, that must be properly identified as such (and added to a to-visit list) by a host prior to having guests, so that said host can take them to see "the cool stuff".
An example would be the Eiffel Tower in Paris, or Dracula's Castle in Transylvania.
A landmark is an important place/monument/building. For instance the Eiffel Tower
What is change of organisms over an extended period of time?
Change of organisms over an extended period of time is known as evolution. Evolution is the process by which populations of organisms change over generations through genetic variation, natural selection, and other mechanisms, leading to the emergence of new species and the diversity of life on Earth.
What is it called when you believe in evolution?
== == Believing in evolution of species is called being realistic. It is recognizing the facts of science. Persons who believe that evolution is true are often referred to as evolutionists.
Persons who are true believers in evolution specifically exclude anything other than a purely naturalistic explanation for the origin of the earth and universe and particularly life on earth.
Theistic evolutionists is a term given to those who try to match theism, or belief in a God or gods as the one or ones involved in an original creation, with evolution being the mechanism which has produced ongoing changes over time to the point where we are today. Sometimes this also includes a God or gods guiding or directing the process of evolution.
When did Charles Darwin come up with the theory of evolution?
Charles Darwin first published his theory of evolution through natural selection in his book "On the Origin of Species" in 1859. However, he started developing his ideas on evolution during his voyage on the HMS Beagle in the 1830s.
If perfect pitch is dominant you could have this.
PP X pp
Then all of the children will have perfect pitch.
If perfect pitch is recessive, then;
pp X Pp
then there is only a 50% chance of any one child having perfect pitch.
In the future be more precise.
Function of phenol DNA extraction?
Phenol is used in DNA extraction to separate DNA from proteins and other contaminants. It denatures proteins and disrupts cell membranes, allowing DNA to be separated and purified. The phenol acts as an organic solvent to extract DNA from aqueous solutions.
What is the phylum of organisms most closely linked to the evolution of land plants?
Charophyta; Specifically stoneworts are within a green alga lineage that million of years ago gave rise to the land plants. They have a distinctive form and sex organs like land plants. -Cengage Learning
