Discussion of everything related to the Theory of Evolution.
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I have learnt that one of the mechanisms of evolution is natural selection. However, how can this give rise to new species? Weren't these species already there in the population as a minority?
My understanding is that new species can appear as a result of geographic isolation, and both populations will adapt differently to their environment. It confuses how new species can appear when organisms best suited for the environment are simply selected for survival (so they were there before).
Maybe I have the wrong concept in my head. I have been trying to understand what actually happens, and any help will be greatly appreciated.
As variations are "selected," what changes over time is the predominant combinations of traits - with a large enough shift in conditions, and/or a decent amount of drift, your eventual "typical" individual in the population (which is, after all, what we call a "species") can be significantly different from the ancestral average.
Evolution is the theory that species adapt due to the needs of their surroundings, for example if a large threat in the ocean suddenly happened ( giant shark, environmental issue) the sea life needs to adapt to those changes in order to survive. This adaption could be to either become bigger or to learn how to adapt to the environmental issues. Evolution does not just happen over night, it takes a while to adapt.
Hope that helps you understand!
They don't change, the POPULATION changes - changes in the environment sort through the living populations, and individuals who "fit" better, with features (adaptations) well-suited to the new conditions, tend to survive, and those adaptations become more common in the next-generation populations. The individuals don't "adapt," in the meaning that word has in English.
Example - in one of the Galapagos Islands a while back, a prolonged drought set in. Many of the local plants went dormant (droughts aren't uncommon there), and only a couple species stayed active: one with large, hard-casing seeds and one with small seeds up in hollows in the plants.
Very quickly, the population of local finches "became" two populations: one with a short, robust beak (they could eat on plant's seeds) and one with a long narrow beak. Individuals with beak variations (adaptations) that could still get seeds survived and made similar babies, those with the "wrong" beaks didn't. If the drought had continued, the two populations might have stabilized as separate species; it ended too soon, and the broad variation of beak types eventually re-emerged in the population.
You can search the result on wiki.
Speciation is the evolutionary process by which reproductively isolated biological populations evolve to become distinct species. The biologist Orator F. Cook was the first to coin the term 'speciation' for the splitting of lineages or "cladogenesis," as opposed to "anagenesis" or "phyletic evolution" occurring within lineages. Charles Darwin was the first to describe the role of natural selection in speciation. There is research comparing the intensity of sexual selection in different clades with their number of species.
There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, parapatric, and sympatric. Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments. Whether genetic drift is a minor or major contributor to speciation is the subject matter of much ongoing discussion.
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Wherever new species come from, Darwin's Theory of Evolution offers nothing in the way of an explanation (the fossil record betrays the theory of evolution, for starters).
Charles Darwin was an amateur biologist who decided to write a book of fiction to try and make some money. His idea was to write a pseudo-scientific creation story that didn't involve some kind of god or supernatural power - a novel idea at the time. (He cleverly based his story on a fact - natural selection - but the rest is pure nonsense.)
His first science fiction book, " On The Origin of Species" was quite popular, so he followed it up with a sequel, "The Descent of Man".
The trouble is, many superstitious, feeble-minded folks got confused and took Darwin's books seriously! This is the bizarre true story of how a fantasy became "established scientific fact"!!
As a creation fairy tale Darwin's theory work just fine, but as science, his theory fails miserably ... as in, totally. Only mendacious charlatans, gullible children and brainwashed simpletons would take this nonsense seriously.
True science per se cannot explain where new species come from, because according to true science, it's utterly impossible for one species to become another species. This mystery goes to show just how overrated and limited science really is.
The topic is Speciation. The father of speciation is not Darwin, it is Ernest Mayr. The topic of speciation employs more principles of biology than any other discipline. Everything from genetics to ecology. It is not a subject that can be fairly treated on a forum. Get Ernest Mayr's book, "Animal Species and Evolution".
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