A sincere question about evolution?

Question

I am asking this with all sincerity because I really do not understand the issue well. Please do not make fun of my intelligence. My I.Q. is very high. This is a topic that I admit I am not very interested in so I do not generally study it at all, but I have this one question that I would like a calm and sincere response to, please.

How can there be new species if two different species will not breed with each other?

I await your sincere and informative responses.

Answer 1

A new species does not come from two other species breeding with each other.  I'll try to explain how it happens with an example:

Say you have some fish living in a river.  They are white colored because they hide in the sand that washes downstream and wait for small fish to swim by to eat them.  Over time, the natural flow of the river separates a branch into an oxbow lake.  Some of the white sandfish are trapped in the lake.  Since the like isn't flowing like the river, the bottom turns into hard clay.  These fish can't hide and wait for food anymore, they have to chase food and catch it.  Some of the fish are naturally faster than others, and those fish survive and reproduce because they can catch more food.  Their offspring are naturally fast, but some are faster than the rest.  Those do a better job of catching food and they reproduce more.  Over time, the fish become faster and more streamlined because that's what makes them better at catching food.  It's simply that the fish that can't catch food as well die more often so they have less chance of passing on their slow genes.  Eventually they get so much faster and more streamlined that they're an entirely new species.  This is not something that happens suddenly, it's a very slow process.  The fish change a tiny bit in each generation, looking at just a couple of generations you wouldn't even be able to tell they were changing.  But they are, slowly and surely.  

Anyway, now you have the fast lake fish, and the slow camouflaged river fish.  The river fish is also different now, a volcano erupted upstream and all the volcanic particles turned the sediment black instead of white, so the river fish has slowly turned black instead of white so that it can keep hiding and catching food.  Now you have two new, different species, but they came from the one original species.  AND the original species might still be around WITH the two new ones.  They just live upstream from the volcano where the sand is still white.

Answer 2

All of the above answers are correct, but they don't explain the mechanisms of evolution, just circumstances.

Firstly, this allopatric speciation and gepgraphical isolation does and can happen. A large example is of Lake Malawi in Africa, there is environmental evidence that it dried up at some point, and the great diversity of fish in the lake can be linked back to that happening.

The circumstances of black/white sand etc. does happen. There is a species of moth that evolved because of this. It doesn't necessarily have to be one group of animals splitting into 2 then evolving seperately, one species can evolve together into a new species. For example these white moths, lived on the white birch tree and so were camouflaged from predators. But after pollution from factories in cities, the birch trees were covered in dirt and so the whitest moths all got eaten. Eventually, only the darkest moths were left and these dark genes were passed on to the future generations leading to the formation of a new, dark coloured moth species.

The reason evolution occurs is because of mutations in species DNA. If for example, one individual in a population of finches had a mutation in their DNA that made their beak larger than usual. This may not lead to anything, since generally, a large beak is of no advantage or disadvantage and so the gene is just present but not dominant in the population. If however, ther was suddenly a shortage of medium sized seeds that the birds with medium sized beaks ate (such as in a 1972 drought in Galapagos) and the only seeds available were very large, then only the birds with the large beaks would be able to eat them and survive. If all the birds with medium beaks die, or are too weak to reproduce, it will be the large beak genes passed into the next generation. If this went on long enough, it would eventually lead to a new species with large beaks.

This has been observed in nature in recent times, not just people guessing it happened millions of years ago.

Really, the reason species evolve is not because of two different species mating (although this can occur its called hybridization) but because of mutations in the DNA that can offer a benefit to those individuals if the right circumstances arise. Admittedly this a very rare and long process, and the species diversity we see today has happended over millions and millions of years, to produce the levels of complexity in mammals etc.

But if you want proof, look at an organism that has a short generation time such as bacteria that reproduce every minute or so in the right conditions. MRSA is a virus in hospitals that is evidence of a bacterial species evolving an immunity to antibiotics, and so it survives in hospitals even when other bacteria don't. This would have originally been one bacteria with a mutant resistance gene that reproduced even in the presence of antibiotics and so outlived all of the other non-mutant bacteria.

Hopefully these examples can convince you that evolution does happen. And with the finches, yes, they are all finches, but different species of finches so they cannot interbreed. These are just small examples of species evolving within a family group, so finches evolve into different finches. But, over very long periods of time, after many many mutations, evolution can produce completely new types of animals. So, for example, fish in the water swam, but some mutated and evolved leg type appendages that allowed them to attach and 'walk' along the bottom of the river bed, helpful when there is a strong current so you don't get washed along. So this 'leg' gene stuck around in the population. Then some of these fish with 'legs' were able to crawl onto land as the legs evolved to be longer. But since they were fish they couldn't breathe on land. Maybe there was a shortage of food in the river, and there was more on land. So those fish that could survive longer out of water could benefit most. Eventually the survival time out of water got longer. More mutations occurred that developed lung-type things in the fish and they could then breathe on land, sort of, just returning to the water occassionally. Eventually, the lungs developed and we get the formation of species of amphibians like frogs, newts etc.

Obviously this is very simplified, and it takes MILLIONS of years, but you can see how it would happen.

There are two factors needed for evolution. The random mutation of DNA to make a change in an individual, and the right circumstances in environmental change for this mutation to then be beneficial. The chances of this happening are very very small which is why evolution is a slow process. But it does happen.

Answer 3

Actually, closely related species can interbreed. But even without that, genetic drift can cause two isolated populations to become different from each other over time. This is what Darwin observed with Galapagos finches. Another interesting genetic phenomenon is ring species (google it). You can have a series of closely related species, each of which can breed with the adjacent populations, but the two species on the ends can't interbreed. This situation exists with a group of Atlantic gull species.

Answer 4

Species is an imprecise, artificial, man-made classification.  The breeding criterion is an old one, used for an early and convenient definition of a species.  The range of genetic variations is much wider than that.  Each reproductive act, even asexual, results in an organism whose DNA is practically guaranteed to differ in some way from its parent(s).  Usually the variations are small enough   But genetic drift in isolated populations can be enough to prevent interbreeding from succeeding.  I think the best place to start learning is the mechanism of DNA itself.  When you get some idea of how that works, some of the other ideas can begin to make sense.

Answer 5

Secret sauce is 100% correct. But he forgot to explain why such changes occur in the isolated species.

The reason is the physical factors or the climatic effect. The two of the isolated groups may live in different climatic conditions such as high/low temperature, high/low humidity, availability and kind of food, etc. The group at the new place, will try to adopt themselves to the new conditions. So, their genes will start changing and it is also possible that they will start changing in their looks. (remember these changes are not instant, they take 100's of generations).

A small example will help you understand all these processes.

Have you ever heard that caterpillars and other insects which destroy crop have developed immunity against DDT or any other insecticide. How did this happen.? It is the same process. When an insecticide was firstly used on insects, they started dying. But, there would be some insects which were out of range of the insecticide. Slowly, their generations got adopted to live in the atmosphere of that insecticide. So, the got immunity against it, and now they were unaffected by that insecticide.

At this stage they are different from those of their primitives.

They are now evolved.

Answer 6

Evolution didn't happen hun. If you want more info just do a little research, I promise the more you search the more you'll begin to doubt evolution.

Answer 7

It's a good question (when asked sincerely) that cuts to the heart of understanding evolution.

Here's the answer:

1. Imagine that two populations of a species get geographically isolated from each other ... e.g. a river cuts through a valley; climate change causes a valley to dry up and the species gets isolated into separate populations in the mountain ranges; a lake shrinks to become two lakes; a bad winter happens; one population has a major migration to another region; there are dozens of reasons that these isolations occur *ALL THE TIME*.

2. If the two populations are indeed isolated from each other, then they are no longer able to exhange genes.   So any changes (evolution) that occurs in one population ... any mutations that appear, any pressures from the different environments ... cannot cross over into the other population.

3. So changes start to accumulate in the gene pools of the two species.

4. After enough time passes (thousands of generations), there are enough differences in the genetics between the two populations, that they will not, or *cannot* mate, even if they were to come in contact again.

5. At that point they are (as you say) *two* species.  The two populations cannot interbreed.    

6. And from then on, they *CANNOT* exchange genetics.  The temporary isolation caused by geography, is now a *PERMANENT* genetic isolation.   They will never again be able to interbreed and exchange genetics.  And from then on, the two species (while initially looking very similar) will get more and more different as they continue to evolve ... changes in one species having no way to transfer to the other population.

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>"You've depended your explanation for the development of a new species on the initial separation of two groups of the same species, ... Then you say one of the separated groups mutates into a new species. "

No.  I said that *BOTH* populations "mutate" into *two* separate species (although the correct word is "evolve" ... the species develops mutations, and then natural selection keeps those mutations that are best for the species in that environment).  Whether they are a "new" species relative to the ancestor species is irrelevant (to your question).  The important point (as far as your question) is that the two subpopulations accumulate enough mutations (genetic differences) that their DNA is no longer compatible for interbreeding.

Why do you think "the possibility is so remote as to be ludicrous"?  On what do you base that claim?

This kind of isolation happens *ALL THE TIME*. There are many many scientific papers documenting cases of this.   The examples I gave (a river cutting through a valley, a lake drying into two lakes, climate change, major migrations) are just a few examples.   They don't even require separate geography (called allopatric isolation) ... there are other ways that this happens (with names like 'peripatric', 'parapatric', and 'sympatric' speciation ... but you need to understand geographic isolation first as it's the easiest to understand).

Genetic isolation is especially common in species following some event that reduces their population dramatically (a flood, a drought, a famine, a new predator enters the territory, the loss of a major food source, etc. etc.).  These catastrophes also happen *ALL THE TIME*.  That's why so many things go extinct!  But if a species manages to survive a near-extinction, this is often in the form of two or more small  sub-populations surviving in remote regions from each other.  If the populations are not in contact with each other at all, they are ripe candidates for becoming separate species over time.

The reason you are finding this "confusing" is that you are making assumptions about what is or is not "ludicrously" unlikely ... based on just a gut feeling.

If you are really "sincere" in your desire to understand this stuff ... then don't throw out words like "ludicrous", without first really considering whether it is not only possible ... but actually quite common.

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P.S.  Mak's addition to my answer is correct.   If the two environments in which populations find themselves are not only separate but *vastly different* (e.g. different climates, predators, etc.), then this will make the accumulation of different mutations much *faster*.

But my point is that even if the two populations are isolated into two *identical environments* (same climate, same predators), as long as they are not exchanging genes, they will still accumulate genetic differences just by chance mutations that enter and spread into the two populations (something called 'genetic drift').

Answer 8

Evolution is the theory that studies the development of an existing species; changes that take place over a long period of time. Evolution does not explain the origin; that is to say - the creation of a species.

We know that God creates. We are also free to accept that God continues to "create" and/or develop an existing species through a process humanity has dubbed the "Scientific Theory of Evolution".

The problem is that society, in all it's secular-driven anti-Godliness, wants you to think you have to choose between the science of evolution and Inteliigent (Divine) Design.

No, this ideal is fallacious - one does not have to choose between one or the other. As so often is the case, with extreme views, the Truth is somewhere in the middle. The science of evolution and Intelligent Design can and do co-exist quite nicely together.

Truth be told, the Creation process is still going on. New additions to existing species are born all the time. New species of plant and animal are constantly being discovered; "new" in the sense that humanity has just discovered them even though they may have already been around for a long time.

Or, maybe a recently discovered species of plant or animal indeed is new, in that God has just created it

Evolution is nothing a religious person needs to be concerned with; "concerned" in the sense that it seems to imply there is no such thing as Intelligent Design.

Answer 9

Let's use the dogs as an example. They are all the same species and can interbreed with other dogs of different kinds. Now, kill off every breed except the chihuahua and the great dane. You now have two species with no interchange of genes, at least not by natural means.

Sure, this is far-fetched but the same thing occurs in nature, as in the salamander genus Ensatina. Google "Rassenkreis", if you are interested.

Answer 10

Many Species can interbreed but the offspring are usually but not always sterile

Answer 11

I hope this help, more info can be found at the website below!

Speciation

What Is a Species?

One of the best definitions is that of the evolutionary biologist Ernst Mayr:

A species is an actually or potentially interbreeding population that does not interbreed with other such populations when there is opportunity to do so.

Note: sometimes breeding may take place (as it can between a horse and a donkey) but if so, the offspring are not so fertile and/or well adapted as the parents (the mule produced is sterile).

Allopatric Speciation: the Role of Isolation in Speciation



The formation of two or more species often (some workers think always!) requires geographical isolation of subpopulations of the species. Only then can natural selection or perhaps genetic drift produce distinctive gene pools.

Link to discussion of gene pools and the forces that alter them.

It is no accident that the various races (or "subspecies") of animals almost never occupy the same territory. Their distribution is allopatric ("other country").

The seven distinct subspecies or races of the yellowthroat Geothlypis trichas in the continental U.S. would soon merge into a single homogeneous population if they occupied the same territory and bred with one another.

Darwin's Finches

As a young man of 26, Charles Darwin visited the Galapagos Islands off the coast of Ecuador. Map

Among the animals he studied were 13 species of finches found nowhere else on earth.

Some have stout beaks for eating seeds of one size or another (#2, #3, #6).

Others have beaks adapted for eating insects or nectar.

One (#7) has a beak like a woodpecker's. It uses it to drill holes in wood, but lacking the long tongue of a true woodpecker, it uses a cactus spine held in its beak to dig the insect out.

One (#12) looks more like a warbler than a finch, but its eggs, nest, and courtship behavior is like that of the other finches.

Darwin's finches. The finches numbered 1–7 are ground finches. They seek their food on the ground or in low shrubs. Those numbered 8–13 are tree finches. They live primarily on insects.

1. Large cactus finch (Geospiza conirostris)

2. Large ground finch (Geospiza magnirostris)

3. Medium ground finch (Geospiza fortis)

4. Cactus finch (Geospiza scandens)

5. Sharp-beaked ground finch (Geospiza difficilis)

6. Small ground finch (Geospiza fuliginosa)

7. Woodpecker finch (Cactospiza pallida)

8. Vegetarian tree finch (Platyspiza crassirostris)

9. Medium tree finch (Camarhynchus pauper)

10. Large tree finch (Camarhynchus psittacula)

11. Small tree finch (Camarhynchus parvulus)

12. Warbler finch (Certhidia olivacea)

13. Mangrove finch (Cactospiza heliobates)

(From BSCS, Biological Science: Molecules to Man, Houghton Mifflin Co., 1963)  

Since Darwin's time, these birds have provided a case study of how a single species reaching the Galapagos from Central or South America could — over a few million years — give rise to the 13 species that live there today.

Several factors have been identified that may contribute to speciation.