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Guangzhou
Trad climber
Asia, Indonesia, East Java
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Feb 29, 2012 - 06:58am PT
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The first time I had to teach Evolution in a Science Class, I was a bit worried too. I put together this handout for the introduction. I've taught it a few more times and have never had a parental issue.
Didn't paste well, but hope it helps. I can email you the word document is you want. (Has photos to help illustrtate) emmanuel at indoclimb.com
Eman
CLASSICAL EVOLUTIONARY THEORY
A. CHANGE WITHIN A SPECIE
A population of animals or plants represents a gene pool, a set of genes that are passed on to the next generation. As long as the environment is stable there will be little change. If a stress occurs, some animals or plants will die. The ones that live were the ones better able to meet the stress and pass on their genes (survival of the fittest). As the environment changes, the population gene pool shifts and changes thus changing the type of animals too.
B. ORIGIN OF SPECIES
A population becomes split by geography, a mountain rises, a river comes through, a storm separates etc.
1. The populations each adapt to the new environment in which they find themselves.
2. Changes then prevent breeding between the two separated populations
a. environment b. anatomy
c. behavior
3. Finally enough changes occur to give rise to a new specie.
C. EVIDENCES TO SUPPORT THE THEORY OF EVOLUTION
1. Fossils- a record that shows that animals and plants
have been different in the past and that older
fossils are generally less complex than younger fossils.
2. Dating- radioactive dating of carbon 14. Computations from rocks, the solar system and space all independently point to the earth being about 4.5 billion years old.
3. Living examples-
i. Darwin's observation on Galapagos islands of
iguanas, cormorants, turtles and finches.
ii. Australia- animals dramatically different;
a continent that separately early.
4. Homologous structures-
a. hand bones in the whales front fins
b. 5 digit palm in many land mammals
5. Embryonic Development
All vertebrates look remarkably similar in early stages and changes occur later in development of the embryo
a. human embryos have gill slits
b. kidney development in mammals go through the stage found in fish and frogs.
6. Repression and vestigial structures- appendix, tailbone and response to screech .
7. DNA can tell us how close one organism is to another organism and possibly point to evolutionary relationships.
8. Direct observation
a. drug resistance in bacteria
b. insect tolerance to DDT (pesticide)
9. Convergent Evolution (vs divergent)
Whales, seals and sharks body shapes.
PROBLEMS WITH THE CLASSICAL THEORY
1. DNA changes to the benefit of an animal so rarely that the time needed for changes are not statistically possible. Natural selection is too slow to do everything that has happened.
2. The cell is complex and the parts of the cell are interdependent. Since the whole is more than the sum of the parts, how could a cell evolve to its present complexity?
3. 10200 proteins are possible but we find out 100,000 (105) different ones in nature. Why so few choices if more could have evolved?
4.Why have few good links been found between any major groups of animals and plants? Why is there only one land mammal with man's abilities?
5. Miller's experiment- He didn't leave the amino acids in the soup. If he had done so, they would break down as fast as they were made. No stability.
CONCLUSION- There are problems with evolutionary theory but it is a powerful theory that does explain many phenomena which have been observed. No doubt, some genetic changes do occur in nature.
MODIFIERS- Stephen J. Gould and others think that massive radiation and stress caused quick changes in the evolution of life and that this is hard to find in the fossil record. Quantum leaps in specie formation occurred in short periods of time, not gradually like Darwin thought.
Is the issue settled? By no means. Is there one right view? From a scientific viewpoint the book is still open and the final chapter isn't written. Both creationist and evolutionist take much of what they believe on faith, not fact. Thus, the controversy will continue.
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cowpoke
climber
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Feb 29, 2012 - 07:35am PT
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Guangzhou,
Thanks for sharing your handout. I have a suggestion regarding the last couple statements.
Instead of suggesting that faith and science are somehow equitable when it comes to a reliance on faith -- this undermines the value of both faith and science, and encourages students to think in simplistic either/or manners -- help students understand what the National Academies (and many, many others) are trying to impress on teachers and students (I embedded the full statement earlier in this thread):
"Attempts to pit science and religion against each other create controversy where none needs to exist."
Apologists on both sides of this created controversy continue to pit where pitting simply does not add value to our understanding and experience, and implicitly violate fundamental propositions of both perspectives, one of which is concerned with observation of the natural and the other with belief in the supernatural.
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healyje
Trad climber
Portland, Oregon
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Feb 29, 2012 - 08:37am PT
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Both creationist and evolutionist take much of what they believe on faith, not fact. Thus, the controversy will continue.
This is not the case at all, science does not operate on faith, but rather facts and proven theories. Not all facts are known and we don't have theories for every observed phenomena, but in science ideas around observed phenomena make a rigorous journey from observation to hypothesis to theory. No such rigor exists in religion, creationism or ID - to equate them is not an act of neutrality, but rather one of active support for creationist views.
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Jan
Mountain climber
Okinawa, Japan
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Feb 29, 2012 - 10:20am PT
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Yes, I think it is much better to keep them in separate realms.
No need to deny or denigrate, just note that they address different aspects of life.
If you want to understand the physical world stick with science.
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Ed Hartouni
Trad climber
Livermore, CA
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Feb 29, 2012 - 10:40am PT
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I believe the Miller-Urey experiments assumed atmospheric conditions that may not have existed on the early Earth, you might want to research that a bit more...
e.g.
http://cips.berkeley.edu/events/planets-life-seminar/kasting.pdf
Annu. Rev. Astron. Astrophys. 2003. 41:429–63
EVOLUTION OF A HABITABLE PLANET
James F. Kasting and David Catling
Abstract Giant planets have now been discovered around other stars, and it is only a matter of time until Earth-sized planets are detected. Whether any of these planets are suitable for life depends on their volatile abundances, especially water, and on their climates. Only planets within the liquid-water habitable zone (HZ) can support life on their surfaces and, thus, can be analyzed remotely to determine whether they are inhabited. Fortunately, current models predict that HZs are relatively wide around main-sequence stars not too different from our sun. This conclusion is based on studies of how our own planet has evolved over time. Earth’s climate has remained conducive to life for the past 3.5 billion years or more, despite a large increase in solar luminosity, probably because of previous higher concentrations of CO2 and/or CH4. Both these gases are involved in negative feedback loops that help to stabilize the climate. In addition to these topics, we also briefly discuss the rise of atmospheric O2 and O3, along with their possible significance as indicators of life on other planets.
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Largo
Sport climber
The Big Wide Open Face
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Feb 29, 2012 - 11:26am PT
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Both creationist and evolutionist take much of what they believe on faith, not fact. Thus, the controversy will continue.
This is not the case at all, science does not operate on faith, but rather facts and proven theories.
---------
I question this and have all along. For instance, you said that scientists have licked "Two of the three basic elements for creating an artificial cell have been accomplished - the cell membrane and nuclear DNA. What remains, as Largo would point out, is an operative, integrated energy source to drive the system."
This statement rests on the faith that life itself can be reduced to its observable parts, and that "creating" life is basically a delicate job of assembling the right bio crank shafts and ti-rods and gas tanks and motors and, Shezam! "She's alive!" "Alive!"
That million dollar prize is offered because they know it's a sucker's bet playing off the blind spots in people's thinking and beliefs ("I can create life").
I personally have no idea if scientists can ever concoct a cocktail of shite that will start to self replicate and stumble toward complexity but to believe that such a thing is possible simply by assmbling the right chemicals and creating the right atmosphere seems to me as a spectacular leap of faith in bottom-up reductionism. I wonder if the confusion here arises from the fact that bottom-up reductionism works well with extant phenomenon, perhaps less so per the "creation" of things.
My sense of this is still that life is not created in the normal sense of the word, but is something inherent and arises and recurs, and life's energy - which it fundamentally is - cannot be created or destroyed, though the form can change within a system.
Just a few random thoughts.
JL
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WBraun
climber
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Feb 29, 2012 - 11:34am PT
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No scientific advancement of material science can ever produce a living being.
Life is already there perfectly producing living entities since time immemorial.
You can't claim anything that's already being done to begin with.
We will do in the future, their bold claim as they wave their hands thru the air.
That's all it is .... waving of hands thru the air.
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Ed Hartouni
Trad climber
Livermore, CA
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Feb 29, 2012 - 11:53am PT
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There is a lot of hand waving, some of it very evident in this discussion... but I don't think that either Largo or WBraun have contributed any better to the discussion by re-invoking a "life force," which is, after all, a relatively ancient idea that describes a particular attribute of life, that it "animates" matter.
They are certainly free to believe that, but it is an idea that doesn't lend much to the discussion, or to understanding life, especially since we don't know anything about it except that it is necessary for life, it doesn't seem to exist anywhere else, nor is it something that we can learn much about.
But the idea of a "life force" can be used to try to understand the requirements for a theory of life, since the attribute of life, that it utilizes environmental energy assets to power itself, it has a metabolism, has to be explained in any physical theory.
These attributes are likely explained in terms of statistical "laws" averaging over many "simple" interactions resulting in system behaviors which are surprisingly complex given the underlying reactions. Much progress has been made looking at genome expression as a network of chemical reactions which result in proteins that regulate cell life, for instance, in response to the environment. Take cell mass, or reproduction, or chemical stress... all of these can be used, along with the metabolic reaction networks as described by the genome, to predict the response of the cell.
It is a challenge to the physical theory to explain how this class of reactions maintains itself (another characteristic of life) and reproduces. These sorts of studies help point the way to a more general description of life, and lay the foundation for any theory that would seek to explain abiogenesis, where ever it occurs, which is certainly one of the goals of a theory of life.
And this would all happen without resorting to the ancient idea of "life force."
An interesting discussion which probably doesn't quite fit into the OP's intent....
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WBraun
climber
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Feb 29, 2012 - 12:23pm PT
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The early forms of life could be described as Not living in our understanding of life.
That's your incomplete theory, and it's still a guess.
Then you make an Ultimatum.
There was never a moment when it went from non-living to living
This is making sh!t up again.
You don't even have a rudimentary understanding of what "life" really is and it's origin.
Calling "life force" an ancient "idea" is saying that material mechanistic science is the only real branch of knowledge that can actually hold the key to the "science of the soul".
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MH2
climber
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Before Erwin Schrödinger's What is Life, there was Niels Bohr's 1932 "Light and Life" lecture. Max Delbrück was in the audience and may have been influenced by Bohr's suggestion that to understand the nature of life might require new concepts similar to complementarity in quantum physics. However, when Watson and Crick found the double helix structure of DNA, Delbrück was surprised by its simplicity and that only classical chemistry was needed to understand it. He compared it to "a child's toy" according to Gino Segrè in Ordinary Geniuses.
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StahlBro
Trad climber
San Diego, CA
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Call it what you will, but at what point does a construct of inanimate matter become self perpetuating and evolving? That instant has not been adequately explained or even theorized (IMHO). Not saying it is not possible, but still waiting.
Crystals, snowflakes etc. are unique, but they are finite and and don't replicate. What causes this incredible transition?
There is a horizon that must be crossed. It is immense and miniscule at the same time.
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Largo
Sport climber
The Big Wide Open Face
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I don't think that either Largo or WBraun have contributed any better to the discussion by re-invoking a "life force," which is, after all, a relatively ancient idea that describes a particular attribute of life, that it "animates" matter.
There Ed goes again trying to saddle me with pandering some dusty old foggy God-spook-JuJu energetic thing that "animates" life, some non-thing that we all know earmarks the kook and the zany believer.
Actually, you can look at my reference to "energy" as simple bio energy if you want, metabolic juice, or fill in the blank.
I suspect that you think life is simply the product of the bio parts or tissue.
So when a person is alive, and the next minute they die, what "part" suddenly went missing?
JL
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Ed Hartouni
Trad climber
Livermore, CA
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I suspect that you think life is simply the product of the bio parts or tissue.
simple? never said that, certainly you don't get that from my posts
sorry to kid you on the "life force" thing, but you know, we're both getting a bit dusty...
liked your Regan-esque come back too...
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part-time communist
Mountain climber
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I actually started imagining something today, a (technology?) that could be produced far far into the future. Too bad we live in such crummy times that this doesn't exist NOW.
here is what it is: basically a technological projection/particles floating in space that all cumulativey form a very realistic, live, moving, 3 dimensional image of a deceased person. This image could do basic activities like move, talk, and retain the full personality of the person you once knew and loved in the past. Except they would be exempt from all biological requirements of sustenance, therefore take no burden on society. It would essentially be a very complex reproduction of a once-live person, in digital form, replicating its personality, its memories, its thoughts, its identities, etc.(-you could pass your hand through them and it would go right through their body, they have no solid body, just a realistic slightly transparent figure.
It seems like in the distant distant future this technology is feasible maybe.
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part-time communist
Mountain climber
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dunno about free will, it would be produced by advanced technology (so it wouldnt feel any bodily pain, hunger, it would just be an abstract manifestation of the brain, in a visible realistic human form to outsiders (real humans).
the thought experiment demonstrates that because we may head in that direction technologically to produce such things are "reproduction of a human essence (the being of a human, personality, etc.), that such a thing, in fact, may exist.
if you believe the whole idea that technology and science and advancement will lead us closer and closer to the truth of things.
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WBraun
climber
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Largo -- "So when a person is alive, and the next minute they die, what "part" suddenly went missing?"
Most intelligent question ever presented on this forum.
Brilliant!
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rectorsquid
climber
Lake Tahoe
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Most intelligent question ever presented on this forum.
Not really. When I turn off my computer, why does it stop working?
What goes missing is the electro-neural, or whatever they are called, signals that flow through our brains and nervous system. Without those, there is no signal to our heart and it stops beating. Without blood, our cells lack nutrition and eventually die.
Asking such a questions showed a lot of ignorance in biology and was really a troll more than anything. It's like asking why a rock becomes a pile of gravel when you beat on it with a hammer.
Dave
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WBraun
climber
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Most unintelligent answer ever presented ^^^^^
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Largo
Sport climber
The Big Wide Open Face
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When I turn off my computer, why does it stop working?
What goes missing is the electro-neural, or whatever they are called, signals that flow through our brains and nervous system. Without those, there is no signal to our heart and it stops beating. Without blood, our cells lack nutrition and eventually die.
Asking such a questions showed a lot of ignorance in biology and was really a troll more than anything. It's like asking why a rock becomes a pile of gravel when you beat on it with a hammer.
Now, anything that does not bolser a parts-only, reductionistic model is "trolling." Silly rabbit.
What you have presented above is a belief that life itself is equal and no greater than "the electro-neural, or whatever they are called, signals that flow through our brains and nervous system."
If this is so, why do we need a word like "life" to describe what, according to your beliefs, is merely an electro-chemical mechanism? Furthermore, what mechanism causes said "signals" to begin or end, how do these signals start and by what means do they stop?
JL
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Reeotch
Trad climber
Kayenta, AZ
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This is one of the reasons I became a science teacher. Its also one of the biggest reasons I want to quit, right now.
It is important when teaching evolution to be clear about what kinds of questions science can and can not answer.
A lot of the above concerns things science does not have much to say about, yet . . .
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