Save it for another thread; this is for people curious about aspects of evolution and biology as a whole, not a place to debate.
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Save it for another thread; this is for people curious about aspects of evolution and biology as a whole, not a place to debate.No I'm not embarrassed at all, exposing the equivocation fallacy at the heart of Darwinian presuppositional logic is a reasonable first step.
Uh... you wouldn't refer to Homo sapiens as just "sapiens", so don't refer to Pan troglodytes as just "troglodytes". And if you are going to try to refer to chimpanzees using taxonomy, you should refer to bonobos using taxonomy too. Though I can't fathom why you wouldn't just use their common names. The reason you can't just refer to a species without its genus name too is because entirely different organisms can have the same species name if they aren't in the same genus. For example, the Eurasian wren's taxonomic name is Troglodytes troglodytes.Darwin found the definition of species elusive but that's really an ongoing issue for taxonomy. The Troglodytes and Bonobos can still interbreed but they are still distinct species.
For the term "species" to be useful, it actually can't be the same for every Kingdom of organism. It's an entirely different definition when applied to bacteria than when applied to plants, for example.I've always thought it wasn't so much arbitrary as it was a matter of convenience. Maybe the Dewey decimal system works fine in most Libraries but I've found some of my favorite books in some odd places. I found Zen and the Art of Motorcycle Maintenance in the travel section once.
Uh... you wouldn't refer to Homo sapiens as just "sapiens", so don't refer to Pan troglodytes as just "troglodytes". And if you are going to try to refer to chimpanzees using taxonomy, you should refer to bonobos using taxonomy too. Though I can't fathom why you wouldn't just use their common names. The reason you can't just refer to a species without its genus name too is because entirely different organisms can have the same species name if they aren't in the same genus. For example, the Eurasian wren's taxonomic name is Troglodytes troglodytes.
For the term "species" to be useful, it actually can't be the same for every Kingdom of organism. It's an entirely different definition when applied to bacteria than when applied to plants, for example.
Being able to interbreed is not the only measure for if two different populations are the same species. Such is why horses, donkeys, and zebras are not the same species, nor are tigers and lions. For example, barriers to reproduction, such as the river that separates bonobos from chimpanzees and keeps the populations from intermingling, are also kept in consideration. Basically, although bonobos and chimpanzees are capable of interbreeding, this is rare in the wild, and they are genetically distinct enough from one another to warrant being labelled as different species.My point was there are two species, yet they can still interbreed.
Absolutely, with guidelines, otherwise it'd be entirely pointless. Unfortunately, life rarely fits into the neat little boxes we try to make for it, making taxonomy one of the most continuously contested and debated aspects of biology.Taxonomy is organized largely for convenience.
I found a brief article on the offspring of a female grizzly and a male polar bear. You would think as distinct as those two species that couldn't happen.Being able to interbreed is not the only measure for if two different populations are the same species. Such is why horses, donkeys, and zebras are not the same species, nor are tigers and lions. For example, barriers to reproduction, such as the river that separates bonobos from chimpanzees and keeps the populations from intermingling, are also kept in consideration. Basically, although bonobos and chimpanzees are capable of interbreeding, this is rare in the wild, and they are genetically distinct enough from one another to warrant being labelled as different species.
Absolutely, with guidelines, otherwise it'd be entirely pointless. Unfortunately, life rarely fits into the neat little boxes we try to make for it, making taxonomy one of the most continuously contested and debated aspects of biology.
The various bear species are very closely related. Both genetics and structure of their bodies show that polar bears, brown and grizzly bears have been separate for a similar time to humans and Neanderthals. (Similar circumstances too, populations isolated and some needing to adapt to a cold environment).I found a brief article on the offspring of a female grizzly and a male polar bear. You would think as distinct as those two species that couldn't happen.
Correction: you would think that it couldn't happen. I would not. I would be interested. I would reflect on the nature of species classification as more a matter of convenience than reality. Convenience, that is, both for nature and the taxonomist. But, no I wouldn't think it couldn't happen.I found a brief article on the offspring of a female grizzly and a male polar bear. You would think as distinct as those two species that couldn't happen.
Here's a far more extreme one: all members of the genus Nepenthes are physically capable of cross-breeding, they are generally separated physically by distance to much to make but a few hybrids exceedingly rare in nature. People like myself that grow them as a hobby certainly enjoy making our own hybrids of them.I found a brief article on the offspring of a female grizzly and a male polar bear. You would think as distinct as those two species that couldn't happen.
Evolution isn't "truth". That's the sort of verbiage philosophers and theologians love, but it's meaningless in a scientific discussion. Evolution is a fact. The theory of evolution explains that fact. You may not like this. You may reject this. But your thoughts and feelings on the subject won't change this.
Since your question doesn't ask about an aspect of biology or evolution in a specific way (example: what is natural selection and how does it work?), I feel no need to answer that. I answer that question in literally every other thread under this subforum that I participate in.
Actually, I'm not the one mixing them up. I actually know what I'm talking about.You're mixing up facts, theories and conclusions.
First off, "simian" can refer to apes or monkeys, so I don't know what ancestor you are trying to refer to. As far as mutations being broken down into individual changes in physiology, remember that it is entire populations that evolve, not individuals. However, I'll try to answer your question to the best of my ability regardless.Maybe this question will be more pertinent. Science has supposedly calculated the number of mutations necessary to go back from man to the nearest simian ancestor. How can that number of mutations be broken down into individual changes, such as the restructured pelvis, vocal cords, feet instead of grasping paws, lack of fur, intelligence, self-awareness, language, etc? I think they would fall far short of the number necessary only through haphazard changes to DNA.
. For simplicity sake, I am going to use the number of base pairs in human DNA for calculations (3 billion) and the low end for the average number of mutations per person that is born (40). Multiplying 3 billion by 0.012 (1.2%) makes for approximately 36,000,000 differences in the base pairs. Divide that by 40, and I get 900,000 individuals as the minimum to be born for humans and chimps to diverge (obviously, more individuals were born than that and this isn't all in one generation). So, let me be very cynical, and say that each of those individuals represents an entire generation, and that each generation is 15 years apart. My result is that human and chimpanzee evolution diverged about 13.5 million years ago.Now I'll use Google to check the actual estimate for that... 12.1 million years ago. Not too bad, considering that I purposely used worst case scenarios.
if those numbers are true then they should be different in about 75% of their genome. but actually they are very similar and belong to the same group (lobe-fins fishes).
Just so you know, mutation increases in populations are not all the same... or linear. Basically, natural selection plays a role in the future genetic diversity of a species to an extreme extent. If a species has been in a relatively consistent environment, adapted to it over the course of millions upon millions of years without significant selective pressures for change, it won't change very much, because it is already as biologically suited to its environment as it's going to get.lets try to do that with the lung fish- coelacanth molecular clock. they both split of about 400my. lets say that every species add about 100 new mutations to the genome per generation. if a generation is about 10 years then we are talking about 40 milion generations*100 new mutations=4 bilion bases difference for each lineage. if those numbers are true then they should be different in about 75% of their genome. but actually they are very similar.
Just so you know, mutation increases in populations are not all the same... or linear. Basically, natural selection plays a role in the future genetic diversity of a species to an extreme extent. If a species has been in a relatively consistent environment, adapted to it over the course of millions upon millions of years without significant selective pressures for change, it won't change very much, because it is already as biologically suited to its environment as it's going to get.
Human evolution is a good example of an evolutionary speed run; how fast evolution can be in a land mammal. Although we take a long time to mature and have offspring, since we care for our offspring, they have far higher survival rates than the hundreds of eggs fish might lay at a time. Furthermore, we are a fairly recent species, so we aren't heavily adapted to any specific environment, making natural selection pressures very high between modern humans and the point at which the lineage of human and chimp diverged.
However, coelacanths and lungfish are derived from ancient species, and the respective environments they have adapted to haven't changed all that much, despite hundreds of millions of years passing. Basically, they've adapted to their respective environmental niche about as far as it can go, so for them, practically all further mutations that impact physiology are going to negatively impact their survival. Unless their environment changes in such a way that change in coelacanth biology will start to become advantageous or even necessary to avoid extinction, they just aren't going to change much.
In summary, if a specific set of adaptations remains that which is best suited to an unchanging environment, then selective pressures dictate favoring no change over any change, causing the buildup of mutations to slow to a crawl. It's also worth noting that organisms that live underwater regularly have slower mutation rates than organisms on land.
ok. but i actually refer to the genetic level. the genetic level is constant and therefore we can calculate the number of generations since their suppose diverge. do you think that lungfish and coelacanth are only about 25% similar in their genome?
No, I don't, however, I fail to find any paper that actually quantifies how genetically similar they are to each other to begin with, so I don't exactly have much to comment on.ok. but i actually refer to the genetic level. the genetic level is constant and therefore we can calculate the number of generations since their suppose diverge. do you think that lungfish and coelacanth are only about 25% similar in their genome?
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