Science & Nature Archive

Friday, February 10, 2017

Upcoming Darwin Day Events

Darwin's BirthdayFebruary 12th is Darwin Day. Many organizations are planning events for this weekend to celebrate. You can check DarwinDay.org for events close to you. Here are a few from across Texas and Oklahoma (well, at least the ones you can still make it to - there were some events earlier this week).


Austin, TX - Center for Inquiry: Darwin Day 2017
Feb 11, 12pm - 5pm

DarwinDay.org Details
Official Event Page
Facebook Page

"FREE event to celebrate the 208th anniversary of Darwin's birth. There will be something for everyone--fun learning activities for children and teens, fascinating lectures and trivia contest for adults, and professional development credit for teachers."


Tyler, TX - Darwin Day Tyler 2017
Feb 10, 5pm - 7pm
Feb 11, 10am - 4pm

DarwinDay.org Details
Official Event Page
Art & Seek Details

"This year's Darwin Day celebration features four main events: two different public science lectures, evolutionary themed video screenings, and a teacher development workshop. There will also be other events for students of all ages at the Discovery Science Place, the University of Texas at Tyler, and Tyler Junior College.

All events are free of charge!"


Nagadoches, TX - Darwin Day at SFA
Feb 10, 1pm

DarwinDay.org Details
Press Release

"The Stephen F. Austin State University Department of Biology will host its second annual Darwin Day program. The program will include a seminar by Dr. Charles Pence, assistant professor of philosophy and religious studies at Louisiana State University. Pence's seminar is titled 'Evolution and Chance: From Darwin to the Pioneers of Statistics in Biology.' "


San Antonio, TX - Trinity University: Panel Discussion on Darwin, Gender, and Race
Feb 15, 5pm - 6.30pm

DarwinDay.org Details

"In celebration of Charles Darwin's 208th birthday join us for a discussion on Darwin, Gender, and Race. Four Trinity professors will provide a panel discussion of Darwin's views on gender and race, the current scientific views on race, and the contributions of minorities and women to evolutionary theory. Following brief introductory comments, the panel will open up for questions from the audience. Also be sure to check out the exhibit at the Coates Library, Third Floor: Who's studying evolution these days? A look at modern scientists; Feb. 8-15."


Norman, OK - Norman Naturalism Group: Darwin Day! Potluck and Speaker: The EVOLUTION of Religion
Feb 12, 5pm - 9pm

DarwinDay.org Details
Official Event Page

"The Norman naturalism Group celebrates Darwin Day 2017 with a pot-luck dinner and speaker. The topic is "The Evolution of Religion". Pull out your best recipe and get ready for some more good eating and good talking."


Thursday, February 2, 2017

Texas State Board of Education Takes a Small Step Backwards on Science Education

TEA LogoAs described in the Austin American Statesman article, Texas education board approves curriculum that challenges evolution, the Texas State Board of Education has approved some troubling language for the state science standards.

If you want to see for yourself the full standards, you can find them here. Here are the four subject to the current controversy:

(3) Scientific processes. The student uses critical thinking, scientific reasoning, and problem solving to make informed decisions within and outside the classroom. The student is expected to:

(A) in all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence, logical reasoning, and experimental and observational testing, including examining all sides of scientific evidence of those scientific explanations, so as to encourage critical thinking by the student;

(7) Science concepts. The student knows evolutionary theory is a scientific explanation for the unity and diversity of life. The student is expected to:

(B) analyze and evaluate scientific explanations concerning any data of sudden appearance, stasis, and sequential nature of groups in the fossil record;

(7) Science concepts. The student knows evolutionary theory is a scientific explanation for the unity and diversity of life. The student is expected to:

(G) analyze and evaluate scientific explanations concerning the complexity of the cell.

(9) Science concepts. The student knows the significance of various molecules involved in metabolic processes and energy conversions that occur in living organisms. The student is expected to:

(D) analyze and evaluate the evidence regarding formation of simple organic molecules and their organization into long complex molecules having information such as the DNA molecule for self-replicating life.

You can read a detailed discussion in a report put out by the Texas Freedom Network, Texas Science Curriculum Standards: Recommendations for Dealing with Pedagogical and Scientific Problems (pdf).


The Bad

Yes, the motivation behind these standards really is to promote creationism / cast doubt on evolution. Here are a few excerpts from that TFN report regarding the motivation behind three of these:

[Regarding 7 B] In a final appeal to preserve his proposal, McLeroy stated that the purpose of his standard was to argue against: "...the idea that all life is descended from a common ancestor by the unguided natural processes."
[Regarding 7 G] During the board debate, McLeroy explained that this standard: "...questions the two key parts of the great claim of evolution, which is [sic] common ancestry by unguided natural processes."
[Regarding 9 D] During board debate, Don McLeroy, R-Bryan, explained that the new standard was "basically an origin of life amendment," referencing public testimony provided previously by Ide Trotter, a well-known promoter of intelligent design."

And the history of the first one, 3A, makes it clear that this was compromise language regarding the strengths and weaknesses gambit so popular among creationists.

Moreover, the Board had actually formed an expert committee to review the standards and make recommendations on improving them, and the committee recommended removing these four particular items because "they were vague, redundant or would require too much time to teach" (quoting the Stateseman article). So, the Board is going against the advice of experts to push standards that were originally motivated by anti-science positions.


The Good

The standards aren't actually that bad. All of them could be handled by textbook publishers and teachers strictly keeping to real science, and not injecting any creationism or other pseudoscience. Let's look at them again on a case by case basis.

(3) Scientific processes. The student uses critical thinking, scientific reasoning, and problem solving to make informed decisions within and outside the classroom. The student is expected to:

(A) in all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence, logical reasoning, and experimental and observational testing, including examining all sides of scientific evidence of those scientific explanations, so as to encourage critical thinking by the student;

Well, it says specifically 'all sides of scientific evidence'. Creationism is manifestly not science, so this shouldn't be a backdoor for creationism. As far as real science, this is a little overwhelming for a high school biology class. I mean, all sides of the scientific evidence supporting evolution in general could be an entire class unto itself. Even 150 years ago, in The Origin of Species, Darwin had an entire tome full of evidence for evolution, and the evidence has only grown stronger and more abundant since.

Granted, there are different 'sides' within current evolutionary biology - the relative influence of genetic drift vs. natural selection, how much of the genome is truly junk DNA vs. possible other functions, etc. So, teachers could delve into these current topics, but it seems a bit of a deep dive for high school biology.

(7) Science concepts. The student knows evolutionary theory is a scientific explanation for the unity and diversity of life. The student is expected to:

(B) analyze and evaluate scientific explanations concerning any data of sudden appearance, stasis, and sequential nature of groups in the fossil record;

Well, if you're sticking to real science, this is simply a discussion of gradualism vs. punctuated equilibrium, and perhaps some background on taphonomy and taphonomic biases in the fossil record. And that's all a decent discussion to have, showing students the evidence in support of both gradualism and punctuated equilibrium. In fact, there's evidence for both, so it's probably not an either/or discussion, but rather how they represent opposite extremes regarding the rates of speciation, and what might drive the different rates of change. Although like I said above, this is getting pretty in depth for a high school biology class.

(7) Science concepts. The student knows evolutionary theory is a scientific explanation for the unity and diversity of life. The student is expected to:

(G) analyze and evaluate scientific explanations concerning the complexity of the cell.

Well, yes, cells are complex. I remember learning about that back when I was in high school, and making a model stuffed full of organelles. And if you really want to get into the origins of the complexity, symbiogenesis is one of the topics to discuss in the origin of eukaryotes. And there's an entire field of study for abiogenesis, concerning how life first arose. But again, this might be more detailed than most people expect from high school biology.

(9) Science concepts. The student knows the significance of various molecules involved in metabolic processes and energy conversions that occur in living organisms. The student is expected to:

(D) analyze and evaluate the evidence regarding formation of simple organic molecules and their organization into long complex molecules having information such as the DNA molecule for self-replicating life.

Lots of good stuff to discuss here, as well. I'm sure that teachers would at a minimum bring up the Miller-Urey experiment, as well as other more recent experiments that used different conditions thought to be more representative of the early earth. Teachers could start discussions on the RNA World. And of course, there's that whole field of abiogenesis that I already linked to. But like I said for each of the other questionable standards, and like the expert committee said, this is getting awfully detailed for a high school biology class that has to cover all the other standards and curriculum.

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So, it's troubling that these standards were motivated by creationist misunderstandings of science, and that the Board members went against the recommendations of experts regarding the standards. But at least the letter of the standards isn't horrible, and textbook publishers and teachers can stick to real science. I just hope teachers with creationist sympathies don't use these standards as an excuse to teach junk science.


Updated 2017-02-03: Made numerous small changes

Friday, January 13, 2017

Evolution Book Available Online - From the Beginning

From the BeginningLet's end the week on a positive note. A few years ago, I bought a children's book about human evolution, From the Beginning: The Story of Human Evolution. It was actually a recommendation on a biologist's website, Pharyngula - An updated book list for evolutionists. As PZ Myers put it, it's "An older book that may be hard to get, but worth it for the wall-to-wall drawings of the organisms scattered along the human lineage, from single-celled prokaryote to modern humans." And I have to agree. It may be a little bit outdated by this point, and I did notice a few places where I would have liked to have seen a few things worded a bit differently, but overall, it's a very good overview of human evolution, going all the way back to the very beginning of life. In fact, I'd even recommend it for adults, not just kids.

Well, I got to thinking about that book today, and did a google search on it. And I found something that made me a little excited. The entire book is available online for free from the author's website. So, now I can recommend it to others whole heartedly, knowing that they don't have to hunt it down, but can access it immediately. So, here's the link:


From the Beginning: The Story of Human Evolution (pdf)


If you want to see some of Peters' other books, you can find them here: David Peters Studio - Books.

Well, I guess I'll have one downer in this post, more of a note of caution. As good as that book is, and as talented as Peters is as an artist, he's gotten into a little bit of academic controversy the past few years. He's come up with rather fanciful interpretations of certain fossils, which haven't exactly been accepted by the mainstream scientific community. You can read more about that here, Scientific American blogs - Why the world has to ignore ReptileEvolution.com. Just keep it in mind if you decide to browse Peters' stuff.

Wednesday, November 16, 2016

Book Review - Future Humans

Scott Solomon, a friend of mine who happens to be an evolutionary biologist, has just released his first book, Future Humans: Inside the Science of Our Continuing Evolution. If that name sounds familiar, it's because I mentioned the book a few months ago in the entry, New Book - Future Humans. Now, as I wrote then, I did read and comment on one of the draft manuscripts for Scott, so I may not be the most impartial of reviewers. But I still liked the book very much and would recommend it to anyone with an interest in ongoing human evolution.

I can't sum it up much better than the description from the publisher's site:

In this intriguing book, evolutionary biologist Scott Solomon draws on the explosion of discoveries in recent years to examine the future evolution of our species. Combining knowledge of our past with current trends, Solomon offers convincing evidence that evolutionary forces still affect us today. But how will modernization--including longer lifespans, changing diets, global travel, and widespread use of medicine and contraceptives--affect our evolutionary future?

Solomon presents an entertaining and accessible review of the latest research on human evolution in modern times, drawing on fields from genomics to medicine and the study of our microbiome. Surprising insights, on topics ranging from the rise of online dating and Cesarean sections to the spread of diseases such as HIV and Ebola, suggest that we are entering a new phase in human evolutionary history--one that makes the future less predictable and more interesting than ever before.

The book is well grounded in evidence. In fact, most of it is about actually observed human evolution, both in our very recent past just prior to the industrial revolution, as well as what can be gleaned in modern industrial societies. Of course, that makes the speculation far less sensationalistic than doe-eyed anime characters or web-footed aqua-people, but you probably won't lose any bets going along with Scott's reasonable inferences.

There were many good passages I could quote from the book, but here's one that I especially liked.

At it's core, evolution is about babies. Forget survival of the fittest - the only reason survival is important in evolution is because you cannot reproduce when you're dead. Ultimately, selection favors whatever traits result in making the most babies, grandbabies, and so on.

Scott went on to explain how natural selection has shifted in modern societies. When the vast, vast majority of people survive into adulthood, it becomes changes to fertility that will have the greatest effect on evolution. And that's exactly what many researchers have found - women having children earlier and entering menopause later, increasing their reproductive years and hence their number of offspring. Of course, the researchers have to use statistical methods to try to tease out cultural and environmental influences from genetic ones, but it really does seem as if these are hereditable, genetic changes. And that's just one of the many lessons I learned from the book.

There's a review in New Scientist some might find useful, Future Humans: Just how far can our evolution go?. You can also read an early version of one of the chapters as an article in Nautilus magazine, The Rhythm of the Tide, describing his trip to Ile aux Coudres, an isolated island in Quebec, to discuss what researchers there had discovered of recent evolution in the island's population.

On a personal note, I can say that it's a very different experience reading a draft as a reviewer vs. reading the completed book for pleasure. There's a bit of stress in reviewing the book, intentionally being critical, and trying to find flaws that could be improved. It was much more relaxing reading the book once it was done, and just enjoying it. (I should add that I reviewed it as a member of his target audience, not an expert in the field. I may like to write a bit about evolution on this blog, but I'm no biologist.)

The book was very interesting. It may be a little advanced for an evolutionary naïf, but if you paid attention in your high school biology class and remember the lessons, you'll probably find this book pretty informative. I definitely recommend it.

Friday, November 4, 2016

Understanding Evolution - Origin of Limbs

This entry is part of a collection on Understanding Evolution. For other entries in this collection, follow that link.


I recently came across and answered a question on Quora that reveals a misunderstanding I've seen before over evolution. The question was If theory of evolution is true, why aren't there more semi-evolved species with hands coming out of their skulls or other half-baked monstrosities?. It seems to be that some people think that evolution works by creating partially complete versions of what will later be a fully fledged feature of an organism. Obviously, that's not the case. So I figured it might help to explain how a trait like our limbs actually did evolve.

Evolution doesn't have any foresight or planning. Every organism that has ever lived is both the end result of all the evolutionary history leading up to it, and a transitional form to whatever it's future descendants might look like (assuming its lineage doesn't go extinct).

In contrast to what that Quora question implied, evolution doesn't work like this:

Not How Evolution Works
(not how evolution works)

Evolution didn't provide us with a partial arm in anticipation of a fully developed arm down the road. We didn't sprout a bicep, then a forearm, and finally a hand to complete our limbs. Genetics just doesn't work that way. If an organism doesn't have any limbs to begin with, it's not going to create a monstrosity with a partial human limb. Evolution only works incrementally, and every step has to be functional, or else the organism won't survive to reproduce.

So, if our ancient ancestors didn't have limbs, but we do now, how did it happen? What were the types of changes that were small enough to be possible through genetic mutation, but useful enough to benefit those organisms?

First of all, our ancient ancestors looked something like this:

MetaSpriggina Reconstruction & Fossil
(source: New fossil find pinpoints the origin of jaws in vertebrates)

Just to be clear, it's very unlikely that that's actually our direct ancestor. It's probably a cousin of our direct ancestor. So, it's more like our great-great-great aunt/uncle. But, just like you're more similar to your human aunts and uncles than to unrelated strangers, our ancestors were probably pretty similar to that creature. And of course, you can go back and find even simpler ancestors that are more ancient, but I didn't want to go through our entire evolutionary history for this entry.

So, that critter is a very early chordate. It's got some of the same features we do - eyes, a brain, a 'spinal' cord, etc. But it's also missing some of the features we have now - a jaw, bones, and most notably for this discussion, limbs. So, what could those first rudiments of limbs have looked like? Probably something like this:

Hypothetical evolution of paired fins and their skeletal supports
(source: Origin and Comparative Anatomy of the Pectoral Limb: Anthony F. DePalma MD, FACS)

Now, I'm going to be completely honest. That picture is informed speculation based on studying modern animals, genetics, and embryology, since no fossils have been found preserving that type of soft tissue, but it should be clear how skin folds leading to fins would have been a pretty small mutation that would have benefitted our swimming ancestors. From that creature in the top of the image, it's also a small step to then split up those now existing fins into several independent fins - giving those organsims more freedom in how to use those fins.

Once our ancestors had simple fins, then it was a series of small incremental steps to get to more complex fins, like shown in this next picture:

Diagrams illustrating hypothetical evolution of the extremities of diapnoan (I), ganoid (H) and elasmobranch (G) from a fin fold supported by a series of similar radial cartilages.
(source: Origin and Comparative Anatomy of the Pectoral Limb: Anthony F. DePalma MD, FACS)

I like this one because it also shows the branching nature of evolution. It wasn't just primitive fins in a straight line to our direct ancestors. As those populations split up, each newly independent population took its own evolutionary path, each finding different strategies for modifying fins. In one particular lineage (L), it created a fin with fairly robust bones.

Now, that lineage kept on splitting, too. Some populations remained in aquatic habitats, so that today you can still find coelocanths which have fins with robust bones like that. But some of the populations became increasingly specialized for amphibious habitats, and eventually some populations even became specialized for fully terrestrial habitats. Take a look at this next picture:

Tetrapod Limb Development
(source: Berkeley - The origin of tetrapods)

Like the caveat I gave above, most likely none of those organisms are direct ancestors of any of the others, but the oldest ones are similar to the actual direct ancestors (they're all known animals from fossil remains). And you can see how each newer organism and newer limb is only a slight change from the previous one, as well as how each organism has a fully developed limb that serves it quite well.

And remember, as populations split off and each go their own evolutionary way, they can all develop their own independent adaptations and ways of using different features. So, from those early tetrapods, different lineages have modified those limbs in remarkably different directions, but all showing the underlying similarity:

Similarity of Vertebrate Limbs
(source: Pinterest)

It's not just limbs. That's how virtually all features have developed over the course of evolution. You've probably seen octopuses and squids, and know that they have pretty complex eyes, with an iris, cornea, lens, retina, etc. But since we know evolution is true, it must follow that even something as complex as that eye must have evolved through small, incremental changes, with each new change being beneficial. And in fact, we actually do have a pretty good idea how it happened:

Stages of eye complexity in mollusks
(source: Evergreen Comparative Physiology of Vision - Cephalopods)

Note that those intermediate steps are found in existing animals. They're not just hypothetically a type of eye that could exist. They're types of eyes that we know, for sure, exist and are used by different species of animals.

So, just to recap, evolution doesn't have foresight or a plan. For that matter, it's not a conscious entity at all, even if anthropomorphizing sometimes helps to explain it. Evolution only works through small incremental changes, and each of the changes has to be beneficial if the organisms are going to survive and pass those changes on to future generations. Every organism alive, past and present, is in a sense the end result of all the evolutionary history leading up to it. But in another sense, as long as they don't go extinct, evolution never stops, so every organism is also a transitional form to whatever its descendants might be.

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Here are two links with more info on vertebrate limb evolution. I already linked to the first one up above, but I wanted to make sure to call it out as being especially informative.


Want to learn more about evolution? Find more at Understanding Evolution.

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