Sphodros atlanticus

By Matt Young
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Photograph by Al Denelsbeck.

Photography Contest, Honorable Mention.

Purseweb spider, showing specialized mouthparts called chelicerae
Sphodros atlanticus – purseweb spider. Mr. Denelsbeck writes, "The business end of a male purseweb spider. While noticeable from above and seeming to take up far more of the spider's body mass than should be necessary, the chelicerae are most impressive from underneath, with very large fangs and serrated edges for gripping prey. Despite that, these are not large spiders – my specimen here is only 10-12 mm in body length. The females are almost never seen, generally remaining inside the lair that provides their name, usually looking like a small twig against a treetrunk (I've searched, but found nothing of the sort so far). Canon 7D, Canon 18-135 STM at 64 mm and 36 mm extension tube, ISO 200, F/13, 1/200 s with custom softbox flash unit."

Evolution revised, by A.I.

By Joe Felsenstein
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[image of Toyota robot]
A robot made by Toyota blows its own horn.
Image from Wikimedia.

 

I happened to type “evolution revised” into my Safari browser, and A.I. kicked in. I try to turn off A.I. as much as I can, but this slipped past me. Here’s what it said:

AI Overview

Evolutionary theory is currently being updated from the traditional gene-centric Modern Synthesis to an “Extended Evolutionary Synthesis” (EES). This revised framework incorporates new research, acknowledging that evolution is driven not just by random genetic mutations and natural selection, but also by epigenetic, behavioral, and environmental factors, alongside rapid, often developmental, adaptation.

Key Aspects of Revised Evolutionary Theory

Four Dimensions of Heredity: Beyond genetics, inheritance includes epigenetic (cellular modifications), behavioral (habits and cultural transmission), and symbolic (language) systems.

Extended Evolutionary Synthesis (EES): Proposes a more comprehensive framework than the Modern Synthesis, integrating developments in evolutionary developmental biology (evo-devo), epigenetics, and phenotypic plasticity.

Role of Plasticity and Environment: Organisms can modify their environment (niche construction) and transmit those changes. Acquired traits can be passed down via non-genetic mechanisms.

Faster, Recent Evolution: Recent studies, such as the analysis of 16,000 ancient genomes, reveal that natural selection has accelerated in some populations over the last 10,000 years, affecting hundreds of genes.

Regressive Evolution: Recognized as a common process where organisms lose complex traits to adapt (e.g., loss of eyes in cave-dwelling fish) to conserve energy in specific environments.

Key texts reflecting these changes include Evolution in Four Dimensions, Revised Edition by Jablonka and Lamb and The Princeton Guide to Evolution.

Any thoughts?

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Craig Venter dies

By Matt Young
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Portrait of Craig Venter
The late Craig Venter. Photograph by Michael Janich. CC BY-SA 3.0.

We received an e-mail just now from Joel Eissenberg, Emeritus Professor of Biochemistry & Molecular Biology, Saint Louis University School of Medicine, saying,

As you may have seen, Craig Venter died yesterday. He played an important catalytic role in accelerating genome sequencing, both for humans and for my favorite model organism, D. melanogaster. His work obviously impacted comparative genomics.

Prof Eissenberg’s post at The Angry Bear is reproduced, with permission, below the fold:

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Chrysemys picta

By Matt Young
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Headshot of painted turtle
Chrysemys picta – painted turtle, Sawhill Ponds, Boulder, Colorado, April, 2026.

As I was preparing this post, I noticed that I had earlier posted two other pictures of painted turtles. In 2015, I displayed a handful sunbathing on a log. The 2010 picture of the underside of the turtle, which shows why they are called “painted,” must have disappeared during the Great Server Crash. I allowed someone to post it in Wikipedia, and you can see it here if you are so inclined.

Worldwide Pinhole Camera Day

By Matt Young
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Rural scene in upstate New York
A rural scene in upstate New York taken with a pinhole camera. The photograph was exposed in about 1972 using a Praktiflex FX with a set of extension tubes and Kodak Tri-X film. The depth of field is virtually infinite, which is to say equally poor at all object distances.

Today is World Pinhole Camera Day, a fact I just learned on NPR yesterday morning. Which is somewhat surprising, because years ago I did some original research on the pinhole camera. Below the fold,…

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