NASA declares the Opportunity rover dead. It landed on Mars in 2004, designed to last three months. Instead it lasted fifteen years, exploring farther than anyone dreamed. That stupendous success makes everyone proud. We only wish that NASA had paid full attention to a fossil that Opportunity photographed on its 34th Martian day.
A fossil on Mars... and
...evidence for life...? are our postings about the fossil.
NASA's Mars Rover Opportunity Concludes a 15-Year Mission, by Kenneth Chang, The New York Times, online 13 Feb 2019.
Opportunity lost: NASA says goodbye to pioneering Mars rover, by Alexandra Witze, Nature, 13 Feb 2019.
To Mars with Love by Patricia Ann Straat will be available soon. She and Gil Levin designed and managed the Labelled Release life-detection experiments aboard the two Viking missions, launched for Mars in 1975.
Loving Mars..., a review by Christopher P. McKay, Astrobiology, 07 Feb 2019.
Life on Mars! has background and updates about the Viking LR experiments.
Our genome is mostly junk. This counter-opinion is a response to the surprising earlier finding that 80% of the human genome is transcribed (ENCODE 2012). Opposing it, W. Ford Doolittle and Tyler D. P. Brunet deconstruct terms like adaptation and function, and take an unusually nuanced look at evolution. For us, the paper was quite instructive. They even mention, without clearly endorsing, the possibility that some of the junk DNA, transposable elements (TEs), might have a future use. We welcome the concession, although the required darwinian logic was rather stretched:
|09 Feb 2019
||What'sNEW about HGT ||
It's not that individuals do better (differentially reproduce) within species because they have selfishly accumulating TEs, but that species harboring selfish TE-burdened individuals do better within clades (differentially speciate or avoid extinction) because, just occasionally, a copy of a TE gives rise to a genetic innovation.
Doolittle and Brunet are well aware that horizontal gene transfer (HGT) has a major role in evolution. We wish they would wonder how or where tranferred informational genes got their information. We think darwinian logic does not stretch far enough.
On causal roles and selected effects: our genome is mostly junk, by W. Ford Doolittle and Tyler D. P. Brunet, doi:10.1186/s12915-017-0460-9, BMC Biology, 05 Dec 2017.
Almost 80% of the genome is biochemically active (about ENCODE), posted 06 Sep 2012.
Viruses and Other Gene Transfer Mechanisms is our webpage about HGT.
A lot of organic chemistry is no doubt happening on Titan — Kelly Miller, cosmochemist.
SwRI scientist sheds light on Titan's mysterious atmosphere, Southwest Research Institute, 22 Jan 2019.
Saturn's Biggest Moon Titan May Bake Its Own Atmosphere, by Sarah Lewin, Space.com, 26 Jan 2019.
We think this evidence may point to life.
Thanks, Stan Franklin.
The Society of Genes takes Richard Dawkins's selfish genes a step further. It compares genes to individuals on a kibbutz, where occupations may be subdivided, or to movie actors who change roles. In several examples, the functions of networks and their cascades of logic are especially well explained. Adaptation, or microevolution, gets close attention, and we surmise (from an illustration) that more than a couple of mutations were required for tri-color vision. The writers know plenty about horizontal gene transfer affecting prokaryotes, but disappointingly, not eukaryotes. Thus the genes they need for major innovation, or macroevolution, do not get serious consideration. Still, the analogies, examples and illustrations are commendable, and the writing is friendly.
The Society of Genes by Itai Yanai and Martin Lercher, Harvard University Press, 11 Jan 2016.
|"Gene regulation allows for a wide variety of possible phenotypes from the same set of genes. But not all novelty is the result of mixing and matching. Sometimes new members must be introduced into the society of genes." (p 193)|
...we show that the impact of a Mars-sized planet, ...coinciding with the Moon-forming event, can be the source of major volatiles in the BSE [bulk silicate Earth]. Experimenters at Rice University conclude that the previously-favored scenario for supplying prebiotic organics needed this revision.
Delivery of carbon, nitrogen, and sulfur to the silicate Earth by a giant impact, by Damanveer S. Grewal et al.,
Science Advances, 23 Jan 2019.
A Collision ...May Have Seeded Earth With the Ingredients for Life, by George Dvorsky, Gizmodo, 23 Jan 2019.
Thanks, Karen Riss and Stan Franklin.
13 Jan 2019: a related story prompts our reminder of the software problem.
The RNA World and other origin-of-life theories mentions a variety of scenarios.
Microbial life found under 1,100 meters of ice in Lake Mercer, Antarctica, makes similar life on ice-covered moons elsewhere seem possible, or even likely. Relics of crustaceans and tardigrades were found in the sediments!
Scientists find new evidence of life beneath Antarctic ice by Andrew Freedman, Axios, 17 Jan 2019.
Tiny animal carcasses found in buried Antarctic lake, 18 Jan 2019; and background:
The hunt for life below Antarctic ice, 12 Dec 2018, both by Douglas Fox, Nature.
Thanks, Rob Cooper, Gordon Cooper and Stan Franklin.
Life on Europa, Other Moons, Other Planets?
and Earth-analogs for those environments has links to more.
If you give me 8-mers, I'll give you life. Niles Lehman of Portland State University confidently says so about the origin of life. Last October, in Atlanta GA, he was one of the chemists among geologists, biologists and planetary scientists at an origin-of-life workshop. The theorists are excited about a new possible scenario — 4.47 billion years ago, one or more major glancing impacts left Earth covered in a cloud of molten iron and other debris. When the cloud cooled, a reducing atmosphere favored the formation of organic molecules. These then created life by way of the RNA World.
The hardware aspect of the origin-of-life problem is very far from solved, and theorizing continues unabated. When someone sees a potential workaround for one of the admitted difficultes, a celebration ensues. A few of the other puzzles get mentioned, as if they too will soon be solved. Realistic demonstrations of the whole process are deemed unnecessary. Meanwhile, the software aspect of the problem is completely ignored. We remain skeptical.
How an ancient cataclysm may have jump-started life on Earth by Robert F. Service, Science, 10 Jan 2019.
Thanks, Ted Steele.
The RNA World is our webpage about origin-of-life theories.
24 Jan 2019: a related theory.
From bugs to humans, scientists say we all came from deep space by John Elder, NewDaily, 12 Jan 2019.
...all the central assumptions of the Modern Synthesis (often also called Neo-Darwinism) have been disproved.
— Denis Noble, doi:10.1113/expphysiol.2012.071134, Exp Physiol, 2013.
Thanks, Stan Franklin.
Neo-Darwinism: The Current Paradigm lists some of these assumptions.
In conversation with Prof. Chandra Wickramasinghe..., DailyMirror, Sri Lanka, 03 Jan 2019.
more about Chandra.