the unscientific american watches a mammal walk into the water and grow fins.

[*lifeoftheparty*]

.

[kubiac]

(a) MY ATHEIST, LITERATURE MAJOR'S PERSPECTIVE: Regarding the "environment being given omniscience," my feeling is that this impression (which is widely shared) is the result of a fundamental flaw in human storytelling.

 

The environment is neutral, eternal and probably infinite. It has no opinions and it's not going in any particular direction and certainly not on purpose.

 

But when humans, who live linearly and egotistically, try to explain a vast and vague concept like the "life in the universe," I think they naturally tend to anthropomorphize it, sometimes simply in an attempt to make the "story" more understandable and identifiable to listeners. This can lead to incorrect assumptions about intentionality on the part of "nature." These assumptions about intent, direction or even theme would be potentially true for people but nonexistent and impossible for anything else [in the visible universe that we know of] short of maybe apes, dolphins and parrots. :)

 

(b) Just wanted to say thank you very much to lewelma and the other scientists who took the time to share their knowledge in this thread. You all truly have teachers' hearts.

Edited February 6, 2012 by kubiac

[jar7709]

Yes, thank you all very much for such an informative thread. And I, also, would be interested to know if the books tammyw suggested are recommended by the science-minded folks. Or any other recommended books would be appreciated. For some reason I always just accepted evolution. But I have no idea why. I certainly couldn't have verbalized it. That's scarey! Now I need information to back up my beliefs.

 

 

Yes, this geologist confirms that the books Tammy recommended are great, but the one by Dawkins puts some off, largely I suspect just because it is by Dawkins. (personally I think it is one of his best.) The one by Loxton I also recommended somewhere upthread.

Nmoira's list also has many fabulous books but the Loxton is the most succinct imo.

[Jay3fer]

I found these two pages - written by a religious scientist - somewhat helpful at helping both sides come together:

Top Five Religious Myths Popularly Accepted as Fact

Top Five Scientific Myths Popularly Accepted as Fact

[Mergath]

Yes, I think that is my biggest hang up :)

 

I just can't bring myself to believe that there is no driving force, no reason for it all.

 

I wish that both sides could come together more, and get along.

 

I've always thought it was beautiful, in and of itself, without the need for a sentient "designer." It's like a dance between life and the world it lives on, constantly in flux so that the one can survive on the other.

[lewelma]

I don't know about the other books that have been recommended. I never look at laymen's evolution books, because, I hate to say it, I already know it all. :D

 

I usually recommend Biozone's Evolution http://www.biozone.co.nz/modular.php for people who want to do a self-study on Evolution. It is a 100 page summary of the topic with subtopics including: comparative anatomy, biogeography, natural selection, sexual selection, population genetics, molecular evolution, founder effect, genetic drift, speciation, coevolution, convergent evolution, extinction, etc.

 

I like it because it is not all text. I find reading a long book on a challenging topic to be difficult for me, so I really like this book's style. Each spread has a summary paragraph, a diagram/graph/example, and very difficult and interesting comprehension questions. You can pick it up and read just one spread on one topic and then put it down again. I really like that it hits so many topics within evolution in such a tight way. No rambling, which I hate. It is a high school level text and does assume some knowledge about biology and genetics. The price is right - only $13 and the website has a nice preview and factsheet.

 

Oh, I just checked, and you can get it on Amazon for only $8!! http://www.amazon.com/Evolution-Biology-Modular-Workbook-Serie/dp/1877329886/ref=sr_1_1?ie=UTF8&qid=1328498747&sr=8-1

 

Ruth in NZ

[Snowfall]

If you want to pick an evolution/creation fight, I think there is another thread here that would suit you better than this one. :001_smile:

 

I'm not sure if you were stating that as a general "warning" or saying it to me because I mentioned creationism at all, but I think I was pretty clear that I was not trying to start a creation/evolution fight. That is very specifically why I stated that I am not an atheist - to avoid giving the impression that I am invested in the idea that no god created the universe at some point in time. I don't know that, have no way of knowing that, and don't care about it.

 

What I do care about is the idea that those who believe in evolution must be held to a higher standard of proof and explanation than those who hold other beliefs. I was pointing out only that there is no logical reason that the question of why known life is limited to this planet is one that should be reserved solely for those who believe in evolution. The question is just as rationally posed to those who believe in creation. I did state that a very rare occurrence is more easily explained, to ME, in terms of chance, but I really wasn't attempting debate any more than the person I was responding to was attempting to start a debate. I was simply explaining that there are two sides of that coin. I can see how perhaps that might have been misinterpreted, since I did say that it made more sense to me to ask that question of people who believe there is a plan for it all, so I apologize if that seemed argumentative. It wasn't my intention.

 

In a thread about people having difficulty even understanding evolution (you originally said that the idea was essentially laughable to you) I think it's important to point out when evolution IS being held to a higher standard, because that higher standard is one of the reasons that people do have a difficult time understanding it, IMO. If one of the reasons it seems so absurd is that people are expecting it to explain EVERYTHING, IN DETAIL, while not asking the same of religion, which is required only to refer to God's will as an explanation, then it's important to point it out. It's not an attack on creationism, nor is it an attempt to bring about debate about creation vs. evolution. (Personally, I think that's a false dichotomy anyway, as evidenced by the many people who believe in both. A more concise term might be YEC, since nothing about mere creationism automatically denies evolution.) It's merely a way of showing people that maybe the reason WHY it's more difficult for them to understand evolution is because they are holding it to an unfair standard. I'm obviously not a scientist, lol. I just see a glaring reason why people might have difficulty and feel like pointing it out might help, no science necessary.

 

So again, not sure if you were talking about me at all, but I was definitely not trying to debate.

Edited February 6, 2012 by Snowfall

[lewelma]

one of the reasons that people do have a difficult time understanding it

 

People have difficulty understanding it because it is complex. I mean really really complex. The Origin of Species is >150 years old! Things have come a LOOOOONG way since then. I took graduate level classes on topics like molecular evolution, population genetics, cladistics which are only the tip of the iceburg. We are talking more than 500 hours of study on just these 3 little pieces of Evolutionary studies. I can't even begin to describe what I learned because most people don't have the background in genetics and statistics for me to even start.

 

The field of evolution is HUGE. Biochemistry to Ecology and everything in between. 1000s of peer-reviewed scientific papers published EVERY year. How in the world do you keep up? In the end, you don't. After you have learned the basics (from the point of view of a graduate student) you focus on your one little piece. And the field keeps moving forward at an every accelerating pace. I am now 15 years out of date and that is massive amount of material to learn to come back up to speed.

 

So scientists try to simplify all of this information and research into something that lay people can understand, and often the process of simplification leave huge gaps and confusion, which people pounce on. It is tiring to say the least. I usually just avoid the controversy and keep my head down here, but with people sincerely interested in learning, I was willing to teach.

 

Ruth in NZ

Edited February 6, 2012 by lewelma

[Stellalarella]

I found these two pages - written by a religious scientist - somewhat helpful at helping both sides come together:

Top Five Religious Myths Popularly Accepted as Fact

Top Five Scientific Myths Popularly Accepted as Fact

 

Well, this is interesting to me. Thank you, Jennifer.

[Deniseibase]

I just wanted to chime in here and say that a) this is a very nice thread! and b) I think I have a resource that may help you understand selection a little better.

 

In chapter 3 of Richard Dawkins' The Greatest Show on Earth, he talks about different kinds of selection.

 

First, he talks about humans deliberately choosing plants or animals that we then breed for various traits - think dog breeds and roses and sweet corn here :001_smile: This is artificial selection, and it does indeed have an intelligence doing the selecting.

 

Then, he talks about peahens and peacocks, how the female peahen chooses the most attractive male peacocks to mate with, thereby passing on the genes of the cuter peacocks and NOT passing on the genes of the less cute ones. This is sexual selection, and while it DOES change species over time in the same way human-driven artificial selection does, the peahens are probably NOT thinking "Gee, this male has more to contribute to the standard of my species" in the same way a champion dog breeder thinks about the dogs that are being bred. There is still an agent doing the selecting, but without the same planning and intelligence behind it.

 

Finally, he talks about angler fish, which are those fish that have the bait-like appendages that grow out of their heads, which they use to catch smaller prey fish. These small prey fish 'choose' which angler fish will survive to breed and pass on their genes, in a sense, by being eaten by the angler fish, so there is definitely NOT an intelligent agent making the selection!!! The prey fish are not CHOOSING to be fooled by the bait-appendage, they just ARE because that particular fish has a really efficient bait-appendage. THIS is what is called natural selection, because nature itself is really what is doing the choosing. And from there, just think of all the animals that go and catch their prey & don't even necessarily have to fool them, but just be faster or stronger than their prey and you'll see now we are at the point where there is not an outside agent acting on the species, just the various individuals of that species that do a better job than other members of their same species by being faster or stronger or having a prettier bait-appendage or whatever.

 

I hope that helps - it really helped me understand it, I'm not very scientific either :001_smile: I know Dawkins isn't everyone's cup of tea, but he is a very clear writer and really explains some complex concepts very well.

[Iucounu]

I found these two pages - written by a religious scientist - somewhat helpful at helping both sides come together:

Top Five Religious Myths Popularly Accepted as Fact

Top Five Scientific Myths Popularly Accepted as Fact

Those are inaccurate, and cannot (like other religious materials) be relied on for unbiased information about science. For instance, the "Scientific Myths" page is riddled with falsehoods and straw men.

[lewelma]

I found these two pages - written by a religious scientist - somewhat helpful at helping both sides come together:

Top Five Religious Myths Popularly Accepted as Fact

Top Five Scientific Myths Popularly Accepted as Fact

 

I'm not sure I want to take the time it will take to explain all this, but I will start....

 

His first scientific myth is: Scientific discoveries and the fossil record have proven Darwin's Theory of the Gradual Evolution of Life.

 

Let me explain a bit about gradualism and the fossil record for you to understand why his "myth" is really irrelevant to current thinking.

 

Stephen Jay Gould of Harvard suggested the idea of "punctuated equilibrium" a generation ago to explain gaps in the fossil record. This idea is not contrary to gradualism at all. He simply stated that evolution is not always gradual, sometimes when the environment changes rapidly (like my tree falling in the woods where the snail lives) causes rapid changes in the characteristics of the population.

 

Next, please oh please give me one example in another science where we are held to a 150 year old document!!! DNA was not discovered until 90 years after Darwin published his work, so he did not understand the mechanism of inheritance. His ideas are just the back bone of current knowledge. Like electricity being harnessed in the 1800's leading to computers today. Evolutionary thought has expanded equally rapidly. I really don't need to see Darwin's worries paraded before me. His worries have long since been explained.

 

There are "gaps" in the fossil record because fossils only form under extremely unusual circumstances and then are only dug up by some lucky scientist. If evolution was based solely on the fossil record for evidence we would be in a sad state. Molecular evolution is where the data lie in today's world.

[lewelma]

Well, myth #2 I can't even understand what he is arguing about. All I can say is that "survival of the fittest" is not used by scientists.

 

Myth 3 and 4 are not really about evolution. I could discuss origins of life if people really want, but I think my knowledge of the current research is 15 years out of date. Really a biochemical discussion.

 

Myth #5 goes like this: Very occasionally monkeys hammering away at typewriters will type out one of Shakespeare's sonnets. And he continues: Not true, not in this universe. But it is a popular assumption that the monkeys can do it, a wrong assumption that randomness can produce meaningful stable complexity. But let's look at the numbers

 

I personally don't like this monkey example. But he does miss a very major point. To be comparable to natural selection, the letters the monkeys type would have to be selected to keep words and discard nonsense. And then keep sentences and discard nonsense. And then keep poetry and discard non-poetry etc. This would be comparable to maladaptive traits being lost to the population and and adaptive traits being kept. Then you need a billion years of typing. And, poof, you have a sonnet.

 

But this type of example usually just confuses people. I would rather talk about the real thing than a not-very good metaphor.

[Stellalarella]

People have difficulty understanding it because it is complex. I mean really really complex.

...

 

So scientists try to simplify all of this information and research into something that lay people can understand, and often the process of simplification leave huge gaps and confusion, which people pounce on. It is tiring to say the least. I usually just avoid the controversy and keep my head down here, but with people sincerely interested in learning, I was willing to teach.

 

Ruth in NZ

 

It is complex. When I try to understand it more thoroughly, I come up with more questions; some of my questions are about the science and some of my questions are metaphysical, though to Snowfall I would say that I have not asked those questions on this particular thread, but those questions are definitely swirling in my head.

 

Last week I read a book that finally explained to me how many scientists, working over decades, finally realized that earth had to have a solid core surrounded by a liquid core, then a mantle and crust. When I was a kid I always wondered how in the world scientists could know for sure what the center of the earth was made of, so I felt just giddy to finally understand it. My husband and I were upstairs reading and I actually shook him to get his attention and then babbled on and on about it.

 

It's such a great thing for teachers and scientists to be able to explain a concept and also to explain how scientists arrived at that knowledge.

 

Knowing how, not just what, it makes a big difference to me.

[Carpe]

I personally don't like this monkey example. But he does miss a very major point. To be comparable to natural selection, the letters the monkeys type would have to be selected...

 

Doesn't the Weasel Program do just that?

[lewelma]

First, he talks about humans deliberately choosing plants or animals that we then breed for various traits - think dog breeds and roses and sweet corn here :001_smile: This is artificial selection, and it does indeed have an intelligence doing the selecting.

 

Then, he talks about peahens and peacocks, how the female peahen chooses the most attractive male peacocks to mate with, thereby passing on the genes of the cuter peacocks and NOT passing on the genes of the less cute ones. This is sexual selection, [snip]

 

Finally, he talks about angler fish, which are those fish that have the bait-like appendages that grow out of their heads, which they use to catch smaller prey fish. These small prey fish 'choose' which angler fish will survive to breed and pass on their genes, in a sense, by being eaten by the angler fish, so there is definitely NOT an intelligent agent making the selection!!! The prey fish are not CHOOSING to be fooled by the bait-appendage, they just ARE because that particular fish has a really efficient bait-appendage. THIS is what is called natural selection, [snip]

 

I find it fascinating to see what confuses people. I would never have even thought to discuss this. Thanks for bringing it up.

[ChandlerMom]

I found these two pages - written by a religious scientist - somewhat helpful at helping both sides come together:

Top Five Religious Myths Popularly Accepted as Fact

Top Five Scientific Myths Popularly Accepted as Fact

 

Well, I find these interesting, as long as you don't assume any of the myths (on either side) are generally believed. In other words, I don't think that either group are truly "popularly accepted" at least not among either the scientists or religious people I know. So to me it starts with "myths" I've never believed or would except people to believe and then I wasn't impressed by his counter arguments against these "popular" myths either (just from logic theory, I found the arguments to be terribly flawed).

 

I guess I'm saying I wouldn't look to either list for real information or insight into either creationism or evolution, but I did find it interesting the manner in which the author tried to shoehorn them together. I think the ways in which he succeeds and fails (and the whys) are thought provoking.

 

As to science teachers: about 3/4 accept evolution, but only 1/4 are willing to teach it, mostly due to fear of offending creationist parents, but also because many do not feel confident of their own knowledge (probably because their teachers were also afraid). I really think it is too bad that evolution is so rarely properly taught. Even if evolution was 100% wrong, it disturbs me to think that any current accepted theory isn't being taught in science classes because of political or religious reasons. It's like ignorance is preferable to teaching something that might challenge one's beliefs. I'm not sure it is much different than expunging history of things that don't agree with our worldview, like Japan expunging the Nanking Massacre from their history texts.

 

I admire those who want to learn about evolution, educate their children properly about what it does and doesn't say, and then decide how that fits with your faith. Many thanks to the posters here for their insights and civility.

[Stellalarella]

 

As to science teachers: about 3/4 accept evolution, but only 1/4 are willing to teach it, mostly due to fear of offending creationist parents, but also because many do not feel confident of their own knowledge (probably because their teachers were also afraid).

 

I am sincerely not asking this in a snarky way. Please. Is this information from a study or survey of science teachers? The reason why I was asking was that another poster had also mentioned teachers (I'm assuming the poster mean US teachers) were possibly afraid.

It hadn't occurred to me that teachers would be afraid to teach it, I just thought they either a) really didn't believe it or b) didn't understand it well enough to answer questions about it.

 

I have not personally read any studies about teacher's knowledge/acceptance of evolution.

[Rivka]

Last week I read a book that finally explained to me how many scientists, working over decades, finally realized that earth had to have a solid core surrounded by a liquid core, then a mantle and crust. When I was a kid I always wondered how in the world scientists could know for sure what the center of the earth was made of, so I felt just giddy to finally understand it. My husband and I were upstairs reading and I actually shook him to get his attention and then babbled on and on about it.

 

Oh, what book?! I have always wondered this very thing!

[justamouse]

As to science teachers: about 3/4 accept evolution, but only 1/4 are willing to teach it, mostly due to fear of offending creationist parents, but also because many do not feel confident of their own knowledge (probably because their teachers were also afraid)

 

You know, all through school I never had a teacher shy away from evolution--but that could very well be because of where I live. My HS bio teacher was a PhD, and a professor, and always was very forthright about it all. (she comes to mind because I adored her-she flicked a fetal pig's eye at us, it was a memorable class).

[Stellalarella]

Oh, what book?! I have always wondered this very thing!

North Pole, South Pole: The Epic Quest to Solve the Great Mystery of Earth's Magnetism

 

 

 

I had to just slog through some of it because my science knowledge is basic. I had just read The Disappearing Spoon, though, and that helped me with parts of the chemistry and physics. I was so hooked, though, that near the last part of the book I couldn't put it down. :001_smile:

[lewelma]

It's such a great thing for teachers and scientists to be able to explain a concept and also to explain how scientists arrived at that knowledge.

 

Knowing how, not just what, it makes a big difference to me.

 

Well, this is where my knowledge might fall over. My research was interdisciplinary between population ecology and statistics. Not evolution. So instead, I can tell you all about predicting population size based on the weather, competition, predation, and the breeding interval of a species using multivariate time series analysis :D

 

I have studied the classic experiments in evolution, however, and could dredge some up for you. Most of them would be old by now. :tongue_smilie:

[kalanamak]

Like the Okapi? It's the giraffe's closest living relative.

 

 

 

I love the zebra stripes on a giraffe personality. They are SO cute in the flesh.

[Stellalarella]

Well, this is where my knowledge might fall over. My research was interdisciplinary between population ecology and statistics. Not evolution. So instead, I can tell you all about predicting population size based on the weather, competition, predation, and the breeding interval of a species using multivariate time series analysis :D

 

I have studied the classic experiments in evolution, however, and could dredge some up for you. Most of them would be old by now. :tongue_smilie:

 

Oh, you've been a great help to me.

 

I think that if I begin reading a few of the books mentioned, I could make my way around.

It was just really nice having someone take my questions. :)

Edited February 6, 2012 by Andrea Lowry

[Stellalarella]

Question on, fellow forum posters, but I am in the central time zone of the US and my children are going to wake up early, so I am headed to sleep.

[jar7709]

I am sincerely not asking this in a snarky way. Please. Is this information from a study or survey of science teachers? The reason why I was asking was that another poster had also mentioned teachers (I'm assuming the poster mean US teachers) were possibly afraid.

It hadn't occurred to me that teachers would be afraid to teach it, I just thought they either a) really didn't believe it or b) didn't understand it well enough to answer questions about it.

 

I have not personally read any studies about teacher's knowledge/acceptance of evolution.

 

 

Some teachers may be afraid to teach evolution, others may have been asked not to by a district or higher power or something, but it my experience (I used to teach community college geology, in an area with a vocal YEC minority) there's a common third reason. We give it short shrift at the intro level because there is SO MUCH ELSE to cover. To delve deeply into the hows and whys of evolution would bog down a class into discussions much like those that often result in locked threads on this board. And we really just needed to move on.

[*lifeoftheparty*]

.

[ChandlerMom]

One more tidbit for thought: we think of life and ourselves as such well 'designed' efficient things, but we carry tons of baggage from our evolutionary past and lots of compromises -- basically as is we'd be one shoddy design!

 

A couple examples of baggage:

1. by the time we're born we're on our 3rd set of kidneys (the first 2 atrophy and are replaced, the first is just like the kidney's of a reptile).

2. Only ~1% of our DNA codes for making proteins; some of the remainder are responsible for turning the DNA code bits on/off, but a lot of that 99% is believed to be remnant DNA -- genetic baggage. We have the genes to make the proteins to smell dozens of underwater substances, but we've lost the ability to turn those genes on -- they're orphaned by evolution.

3. We are wrought with design compromises: we'd be better off without an appendix that we don't need and can burst and kill you, but if it got any smaller it would be more likely to get infected and kills us, so we're stuck with it. The nerve for our voice box travels down the spine past the voice box into our chest then loops back up (unprotected) in the neck -- if you can hit just right in your chest you can lose the ability to speak. It's a straight line in a fish but a 15' detour in a giraffe.

4. every cell in our body has 2 sets of DNA -- one in the nucleus and another different DNA in our mitochondria. The mitochondrial DNA (which we only get form our mothers) is so much like bacterial DNA that some antibacterial medications attack our mitochondria.

 

Anyways, these are all things that make perfect sense form an evolutionary standpoint, but would have been beyond Darwin's imagination 150 years ago.

[lewelma]

See I find this interesting! I completely understand everything else you mentioned.

 

But the angler fish thing! What is the initial event that causes the angler fish to start growing an appendage that mimics bait, in order to entice smaller fish?? THAT is the stuff that boggles my mind! :D

 

Obviously, the fish didn't think, "Hey, I can grow a glowing appendage to catch my dinner!"

 

So, how did that come about??

 

It starts as a mutation in a single individual. Not the whole appendage, mind you, just something odd that attracts a bit of food. Does not even need to be a lot of food, but it still gives that individual an advantage over other individuals. It has more offspring than other individuals, and these offspring carry this trait. These offspring continue on for generations unchanged until another random mutation augments this appendage just a bit more and leads to an even better advantage. Once again, more offspring now carry this enhanced trait. We are talking 1000s and 1000's of generations and multiple mutations. And then you have a really cool appendage that attracts your dinner.

 

Also, what was the INITIAL event that caused certain living things to be bright colors, to show that they are poisonous??

 

the initial event was a random mutation.

[AmericanMom]

the initial event was a random mutation.

 

I get what you are saying about natural selection and random mutations and all that. I don't struggle with that part. But my question (even in ps where I was taught evolution) has always been this. How can 4.5 billion years be long enough for that many mutations of that many things to create the kind of diversity we see? It just doesn't seem long enough. At least not without a "force" behind it, making it happen faster. Sorry if this has already been addressed. I didn't see it in the previous posts.

 

(This is a fascinating conversation; I'm so glad it hasn't gotten out of hand!)

[Iucounu]

Also, what was the INITIAL event that caused certain living things to be bright colors, to show that they are poisonous?? That has always baffled me.... If an insect shows bright colors to warn that it tastes bad... and HE didn't come up with that idea, and the environment didn't come up with that idea.... who/what came up with the idea???

There is no idea. Imagine a drab-colored poisonous prey animal. It gets eaten by a curious predator some of the time, perhaps killing both; lose-lose for the individuals (though from the prey's standpoint at least one particular sort of predator that finds it tasty is less successful, and from the predator's standpoint unsuccessful genes are not passed on). Now imagine some prey animals are born with brighter colors, due to a random mutation. Some of them get eaten too, lose-lose; but every once in a while, for whatever reason, a predator avoids them. Not necessarily because the predator has an "idea" that they're strange, but because they don't fit the mold of whatever the predator-- with its own set of mutations-- is looking for. Perhaps predators simply put on edge by the weirdness of a prey animal that doesn't try to hide-- not the standard model for prey-- would be put off.

 

The brighter-colored prey survives more often than the drab-colored prey, because every once in a while it is not eaten when it would've been if it were drab. Thus the bright-colored prey animals proliferate more than the drab ones. The bright-color-sensitive predators survive more often than the non-sensitive ones, and so they proliferate too.

 

Camouflage wouldn't seem to be much of a help to at least a highly poisonous animal, which already has a defense mechanism that works by deterrence rather than avoidance. For those animals, a warning might be just the ticket for avoiding snap-first-and-ask-questions-later encounters with predators.

 

ETA: I found this informative page on aposematism, warning signals given off by prey animals to advertise the presence of defense mechanisms.

Edited February 6, 2012 by Iucounu

[*lifeoftheparty*]

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[kalanamak]

Reading these two books really helped me get a better grasp on evolution. As a non-science-y person, I really enjoyed both!

 

http://www.amazon.com/Evolution-How-Living-Things-Came/dp/1554534305/ref=sr_1_3?s=books&ie=UTF8&qid=1328490045&sr=1-3

 

 

 

Why Evolution Is True is a calm, non-inflammatory book.

David Attenborough's DVD on Darwin is also very interesting: Charles Darwin and the Tree of Life

(Gosh I'm going to miss Sir David when he's gone.)

Edited February 11, 2012 by kalanamak

[*lifeoftheparty*]

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[*lifeoftheparty*]

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[lewelma]

But, and I must add, this level of science is SO far above my head; but, the first thing that pops into my head is how much of our "faulty design" is actually b/c of faulty design and how much can be blamed on what we do to our bodies? Or, I guess, what is done TO our bodies, that we don't know about....

 

The pp was referring to physiological design faults. The physical bone and muscle structure of humans. This is not affected by the environment. Well, perhaps things like rickets affect bone, but rickets does not affect the sperm and egg genes, so rickets is not inherited.

 

The food we eat, the radiation we encounter, too much sleep, too little sleep, overuse of antibiotics, etc. all kinds of things can effect out DNA and stuff like that.

 

When I was reading about stuff in shampoos, I was reading that some of the chemicals that have been labeled as "endocrine disruptors" that are in shampoos, body wash, etc. can enter your bloodstream through your skin. These chemicals can actually enter the fetus of a pregnant woman and affect the child's hormones and predispose that child to certain hormonal related illnesses later in life, like Polycystic Ovarian Syndrome.

Ok, you need to think about what is inherited and what is not. Mutations in cells that are not sperm and egg are not inherited. So you can have mutations in all the other cells and it does not affect evolution. Endrocrine disruptors do not affect the DNA of sperm and egg as far as I know. The fetus's hormones might be effected, but not his/her genes. So any changes this child had would not affect the grandchildren because it could not be inherited.

 

Remember, natural selection ONLY works when the trait acted on is inherited.

[lewelma]

How can 4.5 billion years be long enough for that many mutations of that many things to create the kind of diversity we see? It just doesn't seem long enough. At least not without a "force" behind it, making it happen faster. Sorry if this has already been addressed. I didn't see it in the previous posts.

 

First of all, the mutation rate varies within species. And since it really only matters when the mutation is in sperm and egg cells, the mutation rate also depends on the generation length. This can lead to very complicated calculations. I copied some details below on just bacteria to demonstrate that there is more than enough variability for evolution to work on. Obviously there is less variability in organisms like humans because our generations are very long compared to bacteria and there are not nearly as many of us. But then in our lifetime we have seen new bacteria and virus species evolve to attack humans. So speciation in bacteria and viruses is very quick compared to humans.

 

Mutation Rate in Bacteria

 

When thinking about the rapid rate at which antibiotic-resistant bacteria become selected for in nature, it is important to remember how very small bacteria are and how relatively small volumes can hold astronomical numbers of bacteria.

As an example, the "normal" mutation rate for a gene in nature is about one mutation in every million to every billion divisions. Let's assume then that only one bacterium in 100,000,000 has a mutation in a particular gene. (A mutation rate of 1/100,000,000.) If we compared this with the population of the United States, an estimated 312,919,026 as of 1/27/2012, that would be equivalent to only 3 people in the whole country having that mutation. The population of the world is estimated to be approximately 7, 000,000,000 as of July, 2012. At a mutation rate of 1/100,000,000, only 70 people in the world would exhibit that mutation.

However one milliliter of bacteria (about 10 drops) contains approximately 1,000,000,000 bacteria. This is approximately 3.4 times the population of the United States! The tube below containing 6.5 ml of bacteria growing in broth has a number of bacteria appromately equal to the number of humans on this entire planet!

Assuming approximately 1,000,000,000 bacteria per ml, that means that 10 bacteria in each milliliter from that tube would have a mutation in that one particular gene. Furthermore, since a typical bacterium has in the neighborhood of 3500 genes, that means that each milliliter of that culture contains approximately 35,000 mutations!

Edited February 6, 2012 by lewelma

[lewelma]

But the poisonous/bright color thing.... I still don't get that. So, say this random frog, just one frog, has a random mutation and is born with bright blue stripes on it's back. (Or would the mutation occur AFTER birth?) Wouldn't that bright color on the frog make it easier to see? And therefore a target? If a predator ate that frog, and it tasted yucky, how did the predator pass on that information? And how could that frog pass on its genes, with the mutation, if its bright colors made it an easy target and therefore it got eaten quickly?

 

You are quite clever. I was kind of hoping to avoid this one because I didn't know the answer..... So I went looking through the scientific literature. Here is the intro paragraphs of a peer-reviewed paper which is reasonably easy to understand. Aposematic prey are organisms that have distinctive coloration indicating that they are not good to eat.

 

you can find the full text at http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0005779 This is just one paper out of many. It sounds like there is currently more than one hypothesis about how to explain the evolution of this trait.

 

 

 

The evolution of warning coloration [1] has continued to be a persistent problem for evolutionary biologists. Signals used by aposematic prey increase conspicuousness and/or distinctiveness [2] and will increase the initial probability of attack from predators [3], [4]. If predators are inexperienced, they must sample the aposematic prey to learn the association between the signal and the level of profitability. When aposematism first evolved, all predators were inexperienced and the population of aposematic prey would have been very small. Sampling (killing) would likely have led to an early extinction of this fragile population. A way to circumvent this fundamental problem is to postulate the use of reliable signals, thus removing the need for sampling and learning. It would therefore serve an aposome well to mediate its unpalatability via odorous secretions which can function in such a manner, thus avoiding close contact with the predator [5]. By causing irritation and/or pain when inhaled, such chemicals can give a reliable signal relating to the level of defence. It is difficult to imagine a predator who chooses to attack prey which makes its eyes burn, and causes pain in its respiratory system. In such a case, the chemical secretion is both a signal and a secondary defence component.

 

Olfactory aposematism [6] has not gone unnoticed by biologists. Both Cott [7] and Rothschild [8] discussed the pungent odours emitted by several aposomes. Cott suggested that odours emitted by aposomes may serve as a noxious defence, in addition to being a warning signal. Rothschild also gave examples of odours which themselves are clearly noxious. Prudic [9] and Eisner, Eisner, and Seigler [10] provides a more recent discussion of smelly defensive secretions. However, none of these discusses the potential effects of such secretions on the evolution of warning coloration.

 

We explore the possibility that chemical secondary defence could have set the stage for the evolution of warning coloration. By showing that a reliable chemical signal would select for increased visual conspicuousness, we provide a novel explanation to the evolution of visual aposematism. Speed and Ruxton [11] discussed the role of physical secondary defences in the evolution of aposematism. We modify their simulation model to analyse our hypothesis using a stochastic model.

Edited February 6, 2012 by lewelma

[lewelma]

Ok, looks like all of you have gone to bed. I will be back tomorrow night to answer any more questions that people have.

 

Please keep this thread civil, or it will be closed like the last one.

 

The purpose of this thread is to discuss how evolution works for people who are sincerely interested in learning about the topic. If you want to discuss some other aspect of the larger issue, please open another thread.

 

Off to bed,

 

Ruth in NZ where it is only 8:30pm

Edited February 6, 2012 by lewelma

[lailasmum]

I read through this thread with massive interest and was desperately trying to remember a BBC documentary that was on a few years ago. I finally tracked down a clip from it. It was called Decade of Discovery. Scientists serching for new animals beleive they found a gecko on the point of splitting into two new species. The clip from the show is here, I hope it is viewable outside the UK. The documentary is a couple of years old so I assume there has been follow up work to find out if they were right. It doesn't really go into anything that deeply but is interesting and just over 3 minutes long.

[kiana]

I read through this thread with massive interest and was desperately trying to remember a BBC documentary that was on a few years ago. I finally tracked down a clip from it. It was called Decade of Discovery. Scientists serching for new animals beleive they found a gecko on the point of splitting into two new species. The clip from the show is here, I hope it is viewable outside the UK. The documentary is a couple of years old so I assume there has been follow up work to find out if they were right. It doesn't really go into anything that deeply but is interesting and just over 3 minutes long.

 

Another really interesting thing on the subject of speciation -- http://en.wikipedia.org/wiki/Ring_species

[Kathryn]

Great thread! I'm surprised at how many said that they didn't cover this in school or else not in much detail. Here in the Bible-lovin' South, I was taught all of this, in depth, not only in BIO 101/102, but high school biology and I even remember covering it in middle school (which I remember mostly because of a huge blowup with a very outspoken Christian girl in class).

[Wheres Toto]

I'm really enjoying this discussion and appreciate all the great information being passed along. I have an undergraduate degree in Biology so learned a lot of this in school but I love learning/remembering more details at an understandable level.

 

You know, all through school I never had a teacher shy away from evolution--but that could very well be because of where I live. My HS bio teacher was a PhD, and a professor, and always was very forthright about it all. (she comes to mind because I adored her-she flicked a fetal pig's eye at us, it was a memorable class).

 

I know what you mean. Evolution was pretty much a given in both high school and college. I didn't even realize there was a wide-spread debate until I started homeschooling.

[Beth in SW WA]

:lurk5:

[lewelma]

I'm awake again. :001_smile: If there are any more questions, I can answer them intermittently while I'm teaching.

 

Ruth in NZ

[lewelma]

It's not unlike many other scientific principles explained and understood at a very elementary level. There is often so much information and detail lost in that overly simplistic explanation that it seems like one needs an absolute leap of faith to believe it (so then that leaves one to wonder how that's any different than myth and religion). It takes some people years of study and thought to come to terms with it, so that isn't easily condensed or dumbed down (for lack of a better way of putting it). I also think that for some people the understanding comes more naturally than for others.

 

:iagree:

[Stellalarella]

 

It's not unlike many other scientific principles explained and understood at a very elementary level. There is often so much information and detail lost in that overly simplistic explanation that it seems like one needs an absolute leap of faith to believe it (so then that leaves one to wonder how that's any different than myth and religion). It takes some people years of study and thought to come to terms with it, so that isn't easily condensed or dumbed down (for lack of a better way of putting it). I also think that for some people the understanding comes more naturally than for others.

:iagree:as well. As I posted earlier, this was my experience with learning about the interior of the earth as a child and then as an adult. As a kid, I just had to accept that the diagram in front of me was trustworthy. If I had asked a grade school teacher or even high school teacher to explain how we can accept this as fact, would the teacher have been able to answer me? Hmmm.

 

Our library has two books that were recommended here. "The Beak of the Finch," and "Why Evolution is True." I believe with one of those.

 

I did not expect to be spending hours and hours a week on my own education in order homeschool my children. But happily, that seems to be exactly what is happening. :001_smile:

[lewelma]

I did not expect to be spending hours and hours a week on my own education in order homeschool my children. But happily, that seems to be exactly what is happening. :001_smile:

 

:iagree: I am currently spending hours and hours every week learning formal logic and rhetoric.

[Sebastian (a lady)]

Thanks for braving the explanation.

 

One question I have is what is the line between species and something less differentiated, for example a breed (as in dog and cat breeds). Is this a rather permiable division?

 

I understand, for example that there are different species of bee that generally don't breed, but then my understanding of the "killer bee" developments was that it was one type of South American bee mixing with North American bees and producing something new.

 

Another example of the question might be the division between wolf and dog.

 

The reason I ask is I've tried to get my head around why anthropologists consider different hominids (sp?) to be different species (homo sapiens and neanderthal for example) but then there will be an article saying research suggests they interbred (which to me indicates that they were part of the same species but had different traits emphasized by developing in geographic isolation (much as how we have Asian, African and Nordic populations which have distinct traits that can be very different, but have no issue with interbreeding because they are all one species). [i'm not sure how my tone reads. These are genuine, not baiting, questions.]

 

Actually, I wouldn't mind book recomendations, especially if they were about the nuts and bolts of evolution rather than what it might prove or disprove about the supernatural.

[leeannpal]

Great thread! I'm surprised at how many said that they didn't cover this in school or else not in much detail. Here in the Bible-lovin' South, I was taught all of this, in depth, not only in BIO 101/102, but high school biology and I even remember covering it in middle school (which I remember mostly because of a huge blowup with a very outspoken Christian girl in class).

:iagree:I'm originally from Alabama, and we learned about Darwin, natural selection, survival of the fittest and what macro and micro evolution is. Also, I had never heard of young earth creationists until recently. Everyone I knew that was a Christian understood that evolution was just God's way of creating the earth, and that a literal 6 days were not a requirement for God because He exists outside of time. The Bible clearly also says at one point that "a day is as s thousand years with the Lord..."