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The report below may represent a case of rapid adaptive evolution of a trait: the beaks of Anna’s hummingbirds (Calypte anna) in California, though there are sufficient confounding factors that, were I teaching evolution, I would still use Peter and Rosemary Grant’s work on the beaks of medium ground finches in the Galápagos as my paradigm. (The Galápagos incident occurred over a single year on one small island and confounding factors are virtually nil).

First the species: a male Anna’s Hummingbird flying:

Robert McMorran, United States Fish and Wildlife Service, Public domainvia Wikimedia Commons

and a female hovering:

Mfield, Matthew Field, CC BY-SA 3.0 via Wikimedia Commons

Click below to read the article, and find the pdf here.

The authors posited that the increasing use of hummingbird feeders after WWII would select for changes in the bill length of this species because individuals who could reach and consume more nectar from newfangled feeders (which reward copious nectar swilling) would have a reproductive advantage. Their predictions were met, but there are complications.

Here’s a hummingbird feeder:

Centpacrr at English Wikipedia, CC BY-SA 3.0, via Wikimedia Commons

That’s a very common design, with the feeder filled with sweet liquid: often sugar water, which is okay but commercial nectar containing other nutritive substances is better. The paper describes the spread of feeders and the morphology of AH beaks over time, using about 400 museum specimens gathered since 1860. Feeders, though, were introduced mostly after WWII (from the paper):

Although it likely existed earlier, we report that the widespread recreational hummingbird feeding can be traced back to an article published in National Geographic in 1928 documenting how to ‘tame’ hummingbirds by making bottles of sweet liquid masquerading as flowers (Bodine 1928); this method is thought to have directly influenced the first patented hummingbird feeder in 1947 (True 1995). As a result of this newly popularized feeder, terms associated with hummingbird feeders in local newspapers increased rapidly from southern to northern California, where feeder density began its increase in the historic range accompanied by an increase of ANHU populations as they moved north.

Based on the spread of hummingbird feeders, the authors posited an evolutionary change in beak shape (remember, this is over 80 years):

We therefore expect feeders to select for increased volume with each lick resulting from increased bill length and thickness. In feeders, unlike flowers, nectar pools are not quickly depleted and therefore the short distance between the bill tip and the nectar surface remains relatively constant, such that minimizing the bill-nectar gap allows higher licking rates and extraction efficiency (Kingsolver and Daniel 1983; Rico-Guevara et al. 2015; Rico-Guevara and Rubega 2011; Kingsolver and Daniel 1983).

“Minimizing the bill-nectar gap” involves evolving longer bills. And getting more capacious bills allows you to take in more nectar in one slurp.

And this is what they found.  First, though, there are quite a few confounding factors that the authors had to consider:

• Eucalyptus trees, an invasive species and also a source of food for Anna’s Hummingbird (called AH in this post), also spread over that period
• Humans also spread, and urbanization spread from southern to northern California, so there is a climatic factor to consider, too. Since bills are a source of heat loss, we expect birds in colder climate sin the north to have shorter bills (and they did indeed find this)
• Feeders could have a secondary effect by promoting fights between males, who try to monopolize the “nectar” source. It could be this fighting that would select for changes in bill shape, since bills are used in fighting. Attendant changes in female shape could simply be a byproduct of selection in males.
• Increased urbanization itself could change beak shape, perhaps because it leads to planting of flowers that select for longer bills

Data analysis was done (this is above my pay grade) using a multivariate analysis, taking into account year, location, temperature, beak measurements, and the abundance of feeders and Eucalyptus trees. The latter two factors were estimated—not very satisfactorily—using newspaper mentions since 1880. The results were these:

• The abundance of eucalyptus trees had a small effect on increasing bill length and thickness, but it was much smaller than. . . .
• The density of feeders, which had a highly significant effect, increasing both bill length and thickness (bill dorsal area) in the predicted way
• However, bill size was smaller in colder climates, representing a presumed tradeoff between acquiring nectar from feeders and conserving heat when it’s cold
• Human population size and year also had strong effects, changing the trait in the expected direction, as one would expect if natural selection were causing evolution of bill size and shape over time
• Feeder density had a stronger effect on population size of AHs in northern rather than southern California. From the paper:

We find that feeders and human population size are both strongly positively associated with ANHU [Anna’s Hummingbird] counts (Figure S9) and each appear to have facilitated population growth differently throughout California (Figure 1B,C). Specifically, feeder availability appears to have facilitated population growth at northern latitudes, whereas human population size appears to have contributed more strongly to population growth in ANHU’s native range in southern California. These findings corroborate work conducted by Greig et al. (2017) suggesting that hummingbirds at northern latitudes are more reliant on feeders in winter than those at southern latitudes, while ANHU population growth is supported by urbanized human environments.

Why urbanized environments select for higher hummingbird populations independently of feeders is a bit counterintuitive, but perhaps it has to do with planted gardens.

The upshot:  So, do we have an example of evolution by natural selection here, one based on the proliferation of feeders causing evolution in beak length and shape? It’s possible, but there are a lot of problems. They include a rather small sample size for a model with many covarying factors, the use of newspapers to estimate feeder and Eucalyptus density, an unexplained change in beak shape with feeder density (a constriction appears in the middle of the beak), and no solid evidence that the change is really genetic rather than a change in beak shape induced environmentally by the use of feeders.  (I’ll add, though, that increasing change in time suggests genetic evolution rather than a one-time environmental modification by using feeders.) But the Grants’ work had pretty strong evidence that the change in beak size in the Medium Ground Finch on Daphne Island was genetically based. (They did a heritability analysis.)

One way to test this hypothesis would be to take an area lacking many feeders, but having Anna’s Hummingbirds, and then saturate it with feeders (best to use commercial nectar). If you monitor the birds over a number of years, one should expect to see, in that one small area, a change in beak shape. But nobody is going to do this experiment, because they’d probably expire before it was done. The Grant’s experiment documented change in beak shape over just a single year, and is, to me, far more convincing.

Generation starships may be the only way humans travel to other stars. These hypothetical spacecraft would travel at sub-light speed and take generations to reach their destination. Over the hundreds or even thousands of years, generations of human beings would be born, live, and then die on these ships. Even if that awkward arrangement could be made to work, how would everything else function for so long? What about the spacecraft? What about the AI?

Whether or not we have partial free will could soon be resolved by experiments in quantum physics, with potential consequences for everything from religion to quantum computers

The latest Jesus and Mo cartoon, called “sky,” came with the caption, “Important court case today.” It’s this, from the National Secular Society:

The prosecution of a man on trial tomorrow for burning a Quran could edge the UK “dangerously close to a prohibition on blasphemy”, the National Secular Society has warned.

Hamit Coskun will stand trial at Westminster Magistrates’ Court for protesting against Islamism outside the Turkish Consulate in February. He set fire to a Quran as part of the protest, which led to a man attacking him with a knife.

Coskun was subsequently charged with intent to cause “harassment, alarm or distress” against “the religious institution of Islam”.

And the cartoon reflects the case:

The vividness of your mind’s eye isn't fixed - and training it up is the secret tool of top athletes and businesspeople. Here’s how you can help develop yours

Thousands of fossils from the La Brea tar pits in California show no signs of mammals and birds evolving in response to shifting temperatures over the past 50,000 years

Want to roll an armadillo when you play Dungeons & Dragons, instead of standard dice? Now you can, thanks to a technique for mapping the probabilities produced by any shape

Life is thought to have begun when RNA began replicating itself, and researchers have got close to achieving this in the lab

Imagination isn’t mere childhood whimsy – harnessing its extraordinary capacities can benefit us all

A critical appraisal of the state of the prescription medications in the United States

The post Rethinking Medications: Truth, Power, and the Drugs You Take first appeared on Science-Based Medicine.

2024 was the first single year to surpass the 1.5°C global warming threshold – now scientists predict that a year above 2°C is possible in the near future

Raman spectroscopy uses scattered to identify a substance’s chemical ingredients and is one of the most widely used scientific methods in space exploration. It is used for lunar exploration to identify volcanic minerals, water ice, and space weathering, and has been limited to obtaining data from lunar orbiters. But how can Raman spectroscopy be conducted on the lunar surface to help us better understand our nearest celestial neighbor? This is what a recent study presented at the 56th Lunar and Planetary Science Conference hopes to address as a team of NASA and academic researchers discussed the Raman Cube Rover (R3R), which would be delivered to the lunar surface via the private space company, Astrobotic.

People always want to know what will happen to Earth when the Sun eventually swells up as a red giant. For one thing, the expanding Sun will turn the inner planets into cinders. It will almost certainly spell the end of life on our planet. Mars might become more temperate and hospitable to life. In addition, it could well be a boon for the gas giant Jupiter and its moons. That's because the habitable zone of the Solar System will move outward from where it is now, to a spot encompassing the Jovian system and forcing changes on all of those worlds.

SpaceX’s Starship super-rocket got off to a great start for its ninth flight test, but the second stage ran into a host of issues and made an uncontrolled re-entry.

Researchers have designed a liquid hydrogen storage and delivery system that could help make zero-emission aviation a reality. Their work outlines a scalable, integrated system that addresses several engineering challenges at once by enabling hydrogen to be used as a clean fuel and also as a built-in cooling medium for critical power systems aboard electric-powered aircraft.

Researchers find that iron powder, an inexpensive alternative to activated carbon, does a better job at filtering PFOS from water -- it's 26 times more effective.

Weather forecasts based on AI are faster and sometimes more accurate than traditional ones, but they may miss rare and unprecedented weather events – which are becoming more common as the climate changes

The galaxy cluster Abell S1063 dominates the center of this JWST image. It's a massive cluster of galaxies about 4.5 billion light-years away. While it dominates the picture, it's not the primary target. It serves as a gravitational lens that magnifies even more distant galaxies that appear as glowing streaks of light around its circular edges.

Nuclear Thermal Propulsion (NTP) has stood as a promising potential alternative propulsion technology for decades. Chemical rockets have begun to reach their theoretical maximum efficiency, and their developers have switched their focus to making them cheaper rather than more efficient. NTP should answer that by offering high thrust and specific impulse. NASA's DRACO Program, the standard-bearer for NTP systems, provides a specific impulse of around 900 seconds, about double a traditional chemical rocket, but half that of most ion thrusters. To increase that number even further, researchers at the University of Alabama at Huntsville and The Ohio State University have been working on a novel configuration of NTP called the Centrifugal Nuclear Thermal Rocket (CNTR) that promises almost to double the specific impulse of traditional NTP systems while maintaining similar thrust levels. However, the system has some engineering challenges to overcome, and a new paper coming out in Acta Astronautica describes some incremental progress on making this improved engine a reality.

Matthew sent me this qui, involving ten pairs of photos in Brittanica Education. The object is to see whether you can tell which is generated by AI and which is real.  Click on the headline below to go to the quiz, which is fun to take. After you click on which photo you think is real, the explanation of why you should have known pops up.

Here is one pair of photos, but take the quiz yourself, which is quick.  Matthew says “I got 10/10”, but poor PCC(E) got only 9/10. Some are more obvious than others.

Have a look and then go to the quiz. Give us your score and then beef if you wish. This is the last one: