Science & Nature Archive

Friday, February 12, 2016

Happy Darwin Day 2016

Darwin's BirthdayToday is Darwin Day, the 207th anniversary of Charles Darwin's birth. To quote one of my previous Darwin Day posts, Charles Darwin was "the man who presented evolution in such a way and with sufficient evidence that it became obvious that it was the explanation for how life developed on this planet. Others had ideas of transmutation before Darwin, and Alfred Russel Wallace even came up with a theory of natural selection very similar to Darwin's at around the same time, so it's apparent that humanity would have eventually recognized how evolution works. But Darwin's genius in presenting all the evidence for evolution in the way he did certainly gave the field a huge head start."

If you want to see if there's anything specific going on in your neck of the woods, you can check out the list of events at DarwinDay.org. I couldn't find anything for Wichita Falls, this year. Maybe I can talk my family into watching Inherit the Wind.

To celebrate Darwin Day on this site, I'm going to provide links to a few of my previous entries. This first set of links is entirely to entries specifically relevant to Darwin or written just for Darwin Day.

And while I write way too much about evolution to list all of my evolution entries, here are a few highlights since the previous Darwin Day:

Thursday, January 21, 2016

Science and Engineering Indicators 2016

NSB LogoThe NSF has released their Science and Engineering Indicators report for 2016. It's a great report put out every two years documenting many aspects of Americans' relationship to science and engineering. For the past several reports (2004, 2006, 2008, 2010, 2012, & 2014), I've made it a habit to examine one specific aspect - public understanding of science. In particular, I've examined the data on how many questions people can correctly answer on a short quiz of basic scientific questions, how that has changed over the years, and how the U.S. fares against other countries on those (mostly the) same questions.

For all of the tables I'm about to publish, note that I copied the data and notes from the NSF report, but I've formatted the tables to fit onto this blog. I made the graphs myself to help visualize the data, as these particular graphs weren't in the report.

First, here's the table showing how Americans fared on a question by question basis on some basic scientific facts. The table includes data from 1988 on up to the most recent poll in 2014.

sei_2016_trend.png

Those results aren't particularly encouraging. I point this out nearly every time I cover this report, but around 1 in 4 Americans don't know that the Earth orbits the Sun, and around half of Americans don't know that electrons are smaller than atoms! Those are simple, basic, scientific facts.

To help visualize that data, especially the trends on how it changes over time, here it is plotted on a graph by year.

sei_2016_trend-graph.png

Americans' knowledge has remained largely steady over the past decade and a half, though there were a few changes. Americans' knowledge on antibiotics improved the most, but has kind of plateaued since around 2006. There does appear to be a recent trend of improvement on the questions concerning the Big Bang and human evolution. Hopefully that trend is real and continues on into the future.

Next, here's the table showing how the U.S. compared to other countries.

sei_2016_comparison.png

I played around with different ways of plotting that data, but there's just so much that it's too confusing to put it all on one graph. If you're interested in seeing a graph for each individual question, you can click on the thumbnail below to embiggen* the graphs.

sei_2016_comparison-graph.png
Click to embiggen

However, I did come up with a way to do a comparison of sorts - I took an average of the percentage of people that correctly answered questions. As an example, if it was only two questions, and 100% of people answered the first question correctly, while only 50% answered the second question correctly, the average would by 75%. I did this average three ways - overall, the physical science questions, and the biological science questions. If a country didn't pose a certain question, it wasn't included in that country's average. I admit that this is a very rough way to do a comparison, but here's how each country fared.

sei_2016_comparison-graph_avg.png

The U.S. actually does rather well in this comparison. It's not number 1, but it's not too far off.

I also suspected that America's over-religiosity might be affecting those questions that contradict a literal young earth creationism interpretation of the Bible, so I redid all those averages exluding the Big Bang and evolution questions.

sei_2016_comparison-graph_avg_no_yec.png

As suspected, this did improve America's performance. This is heartening, that creationism hasn't caused huge damage to Americans' scientific understanding overall.

One lesson from this that I've pointed out before, is to keep these results in mind every time you see a poll showing people's attitudes towards anything scientific. For example, every time you see a poll showing that the majority or plurality favor teaching creationism in public schools, or a poll showing high levels of skepticism towards global warming, remember that this is the same public where a quarter of all people think the Sun orbits the Earth, and where half of all people don't realize electrons are subatomic particles. How informed can they be on scientific issues when they don't even know such simple facts?

The other major lesson is that we need to do a lot better job of teaching science. When you live in a democracy and everyone has a say in the government (at least by way of voting for representatives), you really need a well educated populace for it to work effectively. This is especially true of science in the modern age, when so many pressing issues require accurate understanding of science.

I suppose that on the plus side, as much as alarmists decry the falling quality of American education, at least in this one area, the data shows that Americans' knowledge has stayed largely the same. There's definitely room for improvement, but at least we haven't gone backwards.


*'Embiggen' is a perfectly cromulent word.

Tuesday, November 17, 2015

Weird Engineering Unit - The Slinch

Standard MassTechnical fields are full of units that most non-technical people have never heard of. It gets even weirder with customary U.S. units, given the history of how these units came about. The most obscure unit I've ever actually used for real practical applications is the slinch.

If you're not involved in a technical field, you may not be familiar with the idea of coherent or consistent units. Basically, it's the idea that you shouldn't need any fudge factors in an equation because of the units you're using. For example, power can be calculated as a force times a speed, or P=F*V. Using consistent U.S. units gives an answer in ft-lb/sec, while using metric units gives an answer in N-m/sec (also known as Watts). A non-consistent unit of power that most people are familiar with is horsepower. If you multiply force times speed, you then have to divide by a fudge factor of 550 to get your answer in horsepower, or HP=F*V/550. And the fudge factors only work if the inputs are the units you're expecting. If people wanted to use mph instead of ft/s for the velocity, then you'd need another fudge factor on top of that, HP=F*Vmph*(5280/3600)/550. Equations can get pretty messy if you're not using consistent units, having to multiply all those fudge factors together.

In the standard units used for engineering in the U.S., pounds are a measure of force, not mass (this is already a distinction some people are unfamiliar with, confusing weight and mass). The unit for mass, which most non-technical people would already consider an obscure unit, is the slug. But trust me, I use slugs on a nearly daily basis as an engineer. On Earth, a slug weighs approximately 32 lbs (i.e. F=mg). Or for you metric people, it's equivalent to about 14.6 kg (which measure mass, not weight).

But the engineers who do stress calculations don't always use the normal FPS (foot-pound-second) system, because everyone's used to seeing stresses reported in lbs/in², or psi. And if you were using the normal FPS system, your stresses would come out in lb/ft², and you'd have to do a conversion at the end of your calculations to put the results in the psi that most people are used to seeing*. That's not a huge deal for spreadsheets or hand calcs, but it does make it more difficult for certain finite element programs. So, the stress guys sometimes use a different set of units based on pounds and inches, with the mass unit being the slinch. A slinch is 1/12 of a slug (i.e. the ratio between feet and inches). On Earth, a slinch weighs approximately 32/12 lbs, or 2.7 lbs.

Of course, a lot of these weird units could be simplified if all the engineers in the U.S. started using the metric system like the rest of the world, but that's not the way it is right now, so I've got to use units that other U.S. engineers are familiar with. And if Wikipedia is to be trusted, the metric stress guys have their own weird mass unit of glugs in the centimeter-gram-second system.

* Speaking of weird stress units, I remember working with a foreign engineer one time who gave me her results in Pascals, which is the normal metric way to do it. When I asked her to convert her results to U.S. units, she gave them to me in N/ft².

Image Source: Wikimedia Commons, slightly Photoshopped to remove a dead fly

Note that this entry was adapted from a response I left on Quora.

Saturday, October 31, 2015

A Response to Ben Carson's Creation vs. Evolution Video

Note: for a list of all my Carson related entries, go here.

Ben CarsonThis is my third entry inspired by a speech Carson gave a few years ago, but was just posted to YouTube in June of this year. The first entry was Ben Carson Being Noticed by Popular Science Writers, where I mostly described popular science writers' reactions to the video. Then next entry was Yet Another Look at Ben Carson's Views on Evolution - His Creation vs. Evolution Speech, where I mostly explained why this speech made Carson unfit for the presidency. But I didn't really rebut Carson's misinformation in either of those entries. I merely stated how wrong he was, without demonstrating it. That actually was on purpose, since as I wrote in that second entry, "I'm tempted to go into a point by point refutation of Carson, but there are so many falsehoods and misunderstandings, it would make this post extremely long." But, since I know not everybody studies evolution as much as I like to, I realize that not everybody might understand just how wrong Carson is in this video, so I have decided to do a more detailed rebuttal to his claims. Even ignoring politics, this is an opportunity to educate people on some common creationist misconceptions. Like I expected, this has made for a very long post.

First, just to repeat a theme I've written in both of those previous entries, the aspect of this video that's so damning of Carson isn't merely his ignorance of evolutionary theory, but that he was unable to recognize his own ignorance on the issue, and that despite this ignorance, he was arrogant enough to give a prepared lecture to a crowd of people. As I wrote in the second entry, "Most of us are ignorant about a whole range of issues, but we don't go around giving speeches about those issues." How can we trust Carson to recognize his own limitations?

I know this is a long entry. In fact, some individual answers could stand as their own entries. But I decided to address Carson's mistakes on evolution comprehensively, and he had so many mistakes. On the plus side, many of these mistakes are common creationist mistakes not limited to Carson, so addressing them comprehensively does offer an opportunity to educate others. But, if you want to just skim over this entry and only read the portions that catch your eye, that's understandable.

To keep this entry from growing even longer than it is, I mostly limited myself to discussing evolution, even though Carson discussed a few more topics. However, a few of his statements on those other topics were just too tempting to pass up, so they're discussed here, too.

Continue reading "A Response to Ben Carson's Creation vs. Evolution Video" »

Friday, October 9, 2015

If Humans Went Extinct, Would Something Like Us Evolve Again

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


Is the March of Progress InevitableI've seen the question that's the title of this entry many times, most recently on Quora (If all humans died, would we evolve again from apes? and in a comment thread to Aaron Weyenberg's answer to If humans evolved from apes, why are there still apes?. I wrote a response for Quora that I figured I'd adapt for the blog.

It's certainly possible that some lineage of modern ape or monkey could eventually evolve into something like humans (though definitely not exactly the same as us), or given an even longer time, some other lineage not particularly closely related to humans could as well, but it seems extremely unlikely.

The first issue with the question is an assumption I've pointed out before (such as in the entry, Local Church Misunderstands Evolution - Why Are There Still Apes?). This assumption goes back to the Great Chain of Being, that there's a hierarchy of life, with humans at the pinnacle being the most perfectly evolved of all creatures. That's simply not the case. Evolution adapts organisms to their environments. The raw material for this is random mutations, with natural selection acting like a filter to ensure that only beneficial and neutral mutations persist (though that's not the only mechanism in evolution). There's no intention behind the mutations, guiding organisms towards some end goal. It simply adapts them to their current environments, with no foresight to some future species.

Moving on, there is a concept in biology known as convergent evolution. This refers to two separate lineages that didn't originally have the same features both evolving those features independently, 'converging' on the same solution. And it is true that convergent evolution happens quite a bit. Here are a few examples showing how different marsupial and placental mammals have independently evolved similar body types.

Placental Marsupial Convergent Evolution

But convergent evolution is almost always in cases of 'easy' solutions. Let's look at an example separate from those above or from humans - powered flight. Powered flight has only evolved three times in vertebrates (each time by a different path - pterosaurs, birds, and bats), because powered flight is a difficult to achieve strategy. It takes a very specific set of adaptations, and the likelihood of all of these adaptations occurring simultaneously in a single organism is rather small. If birds and bats were to suddenly go extinct, it might be quite some time before another lineage evolved to fill that flying vertebrate niche.

Just focusing on the intelligence aspect of humans, when you look around at other animals, the type of extreme intelligence seen in humans just isn't very common. On land, there are the other apes and elephants that are nearly as smart as us. In the water, some dolphins and whales also approach human intelligence. But none seem to be as smart as us, or at least not in a technologically inclined way.

There's a reason for that. Brains take a lot of energy. Even though your brain is only around 2% of your weight, somewhere around 20% of the calories you eat go to supporting your brain (one source: University World News: The brain - Our most energy-consuming organ). That's a lot of extra food you need to survive compared to a similarly sized animal with a smaller brain. And yes, being clever can help individuals exploit more resources than less intelligent animals, but just by looking at the distribution of intelligence of all the species out there, it doesn't seem like a strategy that natural selection often favors.

Even us humans, who are now so dominant on this planet, wouldn't have looked particularly noteworthy a few tens of thousands of years ago. Genetic studies show that the effective population got all the way down to around 10,000 - 30,000 individuals at some point in the past (more info: Why Evolution Is True: How big was the human population bottleneck? Another staple of theology refuted). That's not a very successful species. Our ancestors were on the brink of extinction, and barely managed to survive.

If some modern lineage of apes or monkeys went down the evolutionary path to extreme intelligence with the high energy requirements of large brains, they might not be lucky enough to survive a similar situation to what caused the bottleneck in our ancestors, and might end up going extinct before their culture advanced to the point where technology made them as successful as us.

Once you start considering the other specializations of humans (bipedalism, long distance running, object manipulation, etc.), the possibility of another lineage evolving into something closely resembling us seems even more unlikely.

Image Source 1: Wikipedia, with further editing by me.

Image Source 2: The Roaming Naturalist, who herself doesn't know where the original came from. Let me know if you recognize it.


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

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