And this is a point often undersold when explaining evolution. Environment and geography are critical to the concept.
The population doesn't necessarily have to drift apart in order to no longer breed. That island of finches were isolated on one island but some of the finches had mutations in order to grow different size beaks to be able to consume another food source.
Sure but the scientific definition of a species is one that can no longer breed with others. Bust specifically to your point about Darwin's Finches, they are a classic example of species radiation. We know because of the location of the island the initial population had to be small. And as soon as the population began to build, various groups of these birds found niches for themselves and went about their business. Now they are not all considered separate species because they can (as far as I know) still breed between themselves. So the total population with a small genetic sample is isolated, but each of the 15 or so types of birds are still doing the business with each other. I hope that makes sense lol
No, it's not. There are multipile definitions of species, because a species is a fuzzy concept - and if it were not, evolution wouldn't happen! However, for most biological purposes, two populations are regarded as different species if they rarely or never interbreed. Not that they CAN'T interbreed, just that they don't. But the important question is, DO they interbreed? These islands are certainly no so far apart that a finch can't fly from one to another easily. But they do not do so.
The number of different species that CAN interbreed is impressively large, you know. There's like a dozen species of Jay, and all of them can interbreed. But they don't. If your restrictive definition of a species were accepted by biologists, the world would lose easily over HALF of all named species! Even worse, sympatric speciation would have to be ignored. This is when a single breeding population gradually separates into two separate species, often sharing the same environment. This can happen due to mutations affecting (to give a few examples) diet, pheromones, courtship displays, color variations, etc. Sympatric speciation events cause gene flows between the two separating populations to gradually be reduced to effectively zero over at least hundreds of generations. And though full breeding isolation is achieved, the ability to interbreed is not diminished for many more thousands of generations. So you might ask yourself, why would biologists choose to define species they way they do, rather than they way you do? What do they gain? (and I gave you a hint when I spoke of breeding isolation and gene flow).
I didn't know they could still breed with each other. So if the two different finches with different beak sizes mate, they may have offspring with different beak sizes? Wouldn't the parents of these offspring have to feed each of their offspring different food sources based on their beak size?
If you look at genus Canis (dogs , jackals, wolves and coyotes) can all interbreed , Zebras and Horses ( genus Equus) can interbreed too . It looks that in many cases genus defines ability to breed not species . According to biology's dictionary : Genus is a taxonomic category ranking used in biological classification that is below a family and above a species level, and includes group(s) of species that are structurally similar or phylogenetically related.
Stephan Jay Gould has an essay on this that explained that evolution goes both ways, with equal propensity. He even postulated that evolution going only one way, or even favoring one direction, from less complex to more complex, would be proof of god or intelligent design, and then he demonstrated that evolution goes both ways equally. What you see, the evolution from simple single cell forms into complex multi cell forms is a function of the Left Wall nature of the problem. While the direction of evolution can be either way, there is a wall it cannot penetrate. Single cell life cannot evolve into less than single cell life, it can get more complex, at that point, when an organism has complexity, it can become more or less complex, and half the time it becomes more complex,half the time less complex. Over time complexity increases, not by design, but by random chance.
If indeed Evolution simply increased in complexity ....would there even be single celled life on this planet? If some entity was directing the process of life....why would it allow adverse mutation?
For fun, can anyone answer this question? Why can't our species, Humans evolve the ability to run as fast as a Cheetah, eyesight of a hawk, hearing and sense of smell like a dog, the strength of a Gorilla along with all of the traits we currently have?
Because our structure did not require these traits in the environment we evolved in. Had you asked the question in another way, such as "Why didn't our species, Humans evolve the ability to run as fast as a Cheetah, eyesight of a hawk, hearing and sense of smell like a dog, the strength of a Gorilla along with all of the traits we currently have?"...it would make more sense.
To expand on the preceding replies, add in the concept that every organism has an energy budget -- the amount of energy it can generate through activities like eating or photosynthesis, and thus the amount of energy it can expend on growth and activity and still reproduce successfully. Every adaptation affects that budget. So evolution is in part a budget-balancing act -- is the given adaptation the most efficient use of the available energy budget? You might ask yourself why humans can't breathe fire. The answer might be that there has simply never been a series of mutations that led to that. But the answer might also be that such an ability, while cool, would use an extravagent amount of our energy budget, leaving such an individual at a reproductive disadvantage compared to organisms with less flashy, but more efficient, adaptations. One reason humans don't run super fast is that 70% of our energy budget goes to our brains. It has been a good tradeoff, because our big brains mean we don't *need* to be able to run super fast -- or have great hearing, or claws, or fur, etc. So once our brains developed to a certain point, there was hardly any evolutionary pressure to develop keen hearing, claws, fur, etc. That meant progress toward those traits basically stopped, and any existing abilities that didn't affect reproductive success began to degrade. If having a great sense of smell is no longer particularly important to survival, then over time a species will see its average sense of smell get worse. We can see that in the human genome today. There are basically two versions of the genes that determine our sense of smell. About half the human population has a good sense of smell; the other half has a much less sensitive sense of smell. The fact that the two versions are distributed more-or-less randomly throughout the human population shows that sense of smell is irrelevant to our reproductive success.
Because human main trait is long distance running, we can run down animals at the hottest time of the day when other predators are looking for a shade. How do you think Erectus was killing antelopes using only a hand-axe ? When you can hunt anything, anywhere, any time of the day speed, eyesight , smell and hearing are needless wasting of energy.
Along with what every one else has suggested, here are a couple of points. Ever seen cheetah's hunt. A large percentage of their kills are stolen, because once the kill is made, so much energy is expended they can't move for a period of time. Lions and hyenas just wander up take the carcase and keep going. Human eyes are actually extremely good for what they do. We have some of the best motion detectors in the business. In terms of strength, everything has a cost. You carry that extra muscle and body mass around, you have to find ways to dissipate the heat such activity creates. On the hot African plains that can be a major issue. Half the fun of evolution is looking at how various organisms have adapted, the trade offs they have made, what they do with what they have
increasing the affected area can include and increase in complexity. Just for a cell to divide is increasing in complexity as now 2 'lives' came from 1. Evolution in 'what' respect? Otherwise that 'term' has not been defined, within an accepted paradigm of natures process. Darwin didnt even use the word, in his book On the Origins of Species, so that aint the 'evolution' that you're talking about. Ok.... 'yes' evolution is a fact and the best method to observe that is with 3 concepts; 1)... each person born, is from the combining of a cell (sperm/egg) from each parent and grow up to be a bit of both, literally alive 2) ... each person came from a single celled life, alive and its evolutionary trail will show itself, thru its development (cell-adult) 3) ...knowledge evolves with the 'word' (we as a people (lives - upon mass) are far more capable, because of knowledge) These truths that i have posted are 'scientific fact'. The honest approach can enable the ultimate comprehension that mankind is just nature learning of itself, consciously. .
All those traits I mentioned require a great deal of energy and that is why not one species could evolve to have them all. All those traits would be useful in most environments for a number of species. A species would overheat too easily if they had all those traits and die. The Human brain uses up a lot of energy and that is why we do have any of the other desirable traits in other species.
Being there is no environmental pressure for humans to evolve those traits to increase our chance of reproduction, there is no move in that direction. Of course, it could be happening but since evolution takes place over such a long time, we will never know.
These are mostly the same arguments, so i'll address them together. The argument here is a false equivalency. The Theory of Evolution is basically a logical problem. It is a False Equivalence. They argue that since living things change, within their genetic parameters, that they also change outside of their genetic parameters. Since moths can be different colors, perhaps they can also become a different creature entirely. This concept is repeated over & over ad nauseum, until it seems not only plausible, but accepted as proven fact. But, as a scientific theory, it has NO evidentiary backup. It is a fantasy.. a sci fi movie that has turned into a cult following. You cannot talk about evolution scientifically, without the discussion devolving into a heated religious discussion. Cries of 'Blasphemy!' are there with the dedicated followers of this sect. It is not science. Evolution is a religion. Unsubstantiated assertions & 'millions of years' are casually tossed about, assuming people will just nod & accept these wild allegations. But some of us are more skeptical, & demand evidence for our scientific views. Show me ONE piece of evidence that proves that living things cannot just vary, but make a genetic leap into a different gene pool. For over 100 yrs, this has been asserted, claiming it happens so slowly, we just cannot see it, but in the fossil record it happened too quickly, & we missed it. This was a fine belief system for the 19th century, but science has 'evolved' to a bit more understanding of how living things work. They do not flit about, genetically, changing with every weather pattern, or developing new genes to adapt to conditions. I am making NO religious arguments. Stick with science. Show me ONE bit of hard evidence... heck, i'm desperate! I'll take FLACCID evidence! Give me ANYTHING that shows how living things can change in their basic DNA. Show me HOW the chimp ancestor went from 20 pair genomes (or whatever), to 24.. or to the human 23 chromosomes. There is absolutely NO evidence that this CAN happen, much less that is somehow DID happen, millions of years ago or yesterday. Scientifically, it is impossible. And please.. don't just do a google search & post a link allegedly 'proving' this. Post the actual evidence.. any experiments, data, & conclusions that ALL of us can examine & make our own conclusion. Don't just give me someone else's conclusion, without any evidence, & expect me to believe it. Remember, what can be asserted without evidence, can also be dismissed without evidence. There still is NO scientific evidence being offered. We are so steeped in propaganda, from preschool to university, that we don't even consider what is fact or not. Nature show after nature show on public television asserts the same assumptions & imaginations, over & over, until our skepticism glazes over & we surrender.. falling in line like lemmings to leap over the logical cliff. They wear us out with assertions, not anything scientific. Here is my challenge: Be skeptical. Question authority. Rebel against the religious programming you've had all your life. Insist on evidence for your scientific views. Try the scientific method.
What BULSH...the claim there is "NO scientific evidence being offered..." is at a minimum, an intellectually dishonest claim. DNA, RNA, ERVs, the fossil record and the fact that modern Biology makes no sense outside of the context of Evolution, are all evidences supporting the Theory of Evolution. Explain human chromosome 2. "...falling in line like lemmings to leap over the logical cliff."...Yes, continue the march of the fundies and dishonestly ignore all the evidence that supports the ToE because it's contrary to your faith. March on.
Yes, there is a big problem with definitions. How do we define 'species'? What indicates a distinct species? Our own definitions are inadequate, sometimes, & don't neatly fit into the puzzle. Perhaps rather than get bogged down in the vagaries of definitions, especially with a term like 'species', we could go with more current science, & address the genetic problem. HOW do you arrive at the variety of species? What causes or allows jumps over the genetic fence & forces increases in genome pairs or chromosomes? This is from the OP: Ok, the question is, 'Does life increase in complexity? We will accept the research of scientists from darwin to anyone who wants to support our hypothesis.. here it is: Evolution is the mechanism that causes an increase in complexity in life forms. If you prefer, you can change the above to 'allows' rather than 'causes'. But that should not change any experimentation, or alter what we are looking for by observation. The basic issue is genetic change.. THAT is what needs to be addressed. We have NO mechanism that can cause OR allow these genetic leaps. Quibbling about wording is merely a deflection.. an avoidance of the subject at hand. Well, i'm not at all sure what you're saying.. just some vague re-assertions about evolution being proven fact. You don't have any mechanism, or evidence, or logical reasoning to support your theory. So as i have said before, 'what can be asserted without evidence, can be dismissed without evidence. 1. being born is proof of evolution? You just have changed definitions. We are debating evolution as a mechanism for increasing complexity & speciation, not as an individual growth process. The dna of a human stays EXACTLY the same, throughout the human growth process. You are just deflecting with incongruous definitions. 2. Ditto. Same argument, same rebuttal. 3. ditto. Read the OP. We are not debating HOW to use the term, 'evolution', as it has many meanings, depending on context. We are debating it as a mechanism of genetic change..
Ok, i will examine your 'evidence'.. NONE. You wave your hands, shout louder, & merely ASSERT what you believe to be true. You assert that 'DNA, RNA, ERVs, the fossil record', etc... somehow PROVES evolution, yet you do not address the basic issue of the OP. You make vague generalities, but have NO evidence to support your claim. Instead of trying to use ALL of the scientific disciplines you mention, try ONE. Give me one that shows the correlation between simple variability, & the broader concept of new genetic material. All science has told us is that creatures do not 'increase' in variability, but DECREASE. That is what adaptation does. It makes fewer traits available. This is science. That is factual. If you are going to assert something we cannot observe, you must show HOW. YOU explain human chromosome 2, if it is a part of your argument. I have posted a question, made the hypothesis, & shown it to be invalid science. It is up to you to provide evidence proving the assertion, not me to respond to any & every deflection. This is a simple scientific exercise. This is not supposed to be a religious argument, yet inevitably, any discussion about evolution has the same hallmarks of a religious debate: cries of 'Blasphemy!' Indignation. Hostility. Name calling. Deflections. I have made my points, logical one.. it is up to you to respond in a scientific & logical manner. You call me a liar, but i have not seen ONE bit of evidence.. someone posted a link, that supposedly proved it, but i examined it & found it to be vague words with NO science or evidence to examine.
It seems to me, you are paying no attention to one of the primary factors that truly effect the complexity of evolving life on this planet. This variable has larger impact on all life everywhere...and is responsible for the entire process. What might this be you ask.....? wait for it........... figured it out yet?.......... try a bit harder, and do not scroll down until you think you know............................ TIME
Here is my theory. We had a hand full of progressive black amino acids and white crystals that got together one day and decided that this whole "nonlife" thing was not "fair", so then they had "relations" and the next thing you know we had life. Of course, this was life in the collective sense.
