Tag Archives: evolution

Moth Jams Bat Sonar

A gray moth with orange highlights called Bertholdia trigona “goes berserk,” making lots of noise above the range of human hearing when a hunting bat approaches, says William Conner of Wake Forest University in Winston-Salem, N.C. Bats rely on their natural sonar to locate flying moths in the dark, but in a lab setup, the bats rarely managed to nab a loud moth.

When researchers disabled the moth’s noisemaking organs, though, bats caught the moths in midair with ease, Conner reported at the annual meeting of the Society for Integrative and Comparative Biology.

Conner says the work is “the first example of any prey item that jams biological sonar.” Conference attendee David Yager of the University of Maryland in College Park says Conner’s experimental paradigm is “very strong, and I do think he has documented jamming by a species of moth.”

Insect-hunting bats and their moth prey have become a classic in the study of evolutionary arms races, Conner says. “This is warfare … The first counter-adaptation is that the insects developed ears.”
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Jamming isn’t the only possible explanation for moth noises, he said. An explosive clicking sound coming back out of the night might startle a bat just a split-second long enough for the moth to get away.

Scientists Learn More About Spider Evolution

Tangled web of spider evolution

It seems that Attercopus is a missing link, capable of producing silk but not of weaving it. “The thing that had been called the oldest known spider we have now shown is in fact more primitive than a true spider,” Professor Selden told BBC News.
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“They’re all microscopic fragments. What you’ve got is a jigsaw puzzle, with half the pieces and no picture on the box lid,” Professor Selden said. “You don’t know what it’s going to be if you haven’t got all the pieces, so having these additional pieces means it changed the idea of what it was.” The finding is important for evolutionary biologists trying to unravel the origin of spider silk.

“The puzzle about silk was this: we knew that it wasn’t used for making webs initially, for catching insects, because there were no flying insects when the earliest spiders were around,” Professor Selden said.

“Here we clearly have a spider-like animal that could produce silk but didn’t yet have these flexible spinnerets for weaving it into webs; we think that this sort of spider would leave a trail of silk as it moved along, using it to find its way back to its burrow.”

Another great example of scientists incorporating new information and adjusting their understanding of what they are studying.

Social Amoeba

Amoebic Morality by Carol Otte

At first their behavior might seem odd; to gather together in the face of starvation surely ought to end in cannibalism or death. Not so, for they are capable of an extraordinary and rare transformation. The amoebas set aside their lives as individuals and join ranks to form a new multicellular entity. Not all the amoebas will survive this cooperative venture, however. Some will sacrifice themselves to help the rest find a new life elsewhere.

These astonishing creatures are Dictyostelium discoideum, and they are a member of the slime mold family. They are also known as social amoebas. Aside from the novelty value of an organism that alternates between unicellular and multicellular existence, D. discoideum is highly useful in several areas of research. Among other things, this organism offers a stellar opportunity to study cell communication, cell differentiation, and the evolution of altruism.

In response to the cAMP distress call, up to one hundred thousand of the amoebas assemble. They first form a tower, which eventually topples over into an oblong blob about two millimeters long. The identical amoebas within this pseudoplasmodium– or slug– begin to differentiate and take on specialized roles.

Another cool example of how life has evolved novel solutions to perpetuate genes.

The Chip That Designs Itself

The chip that designs itself by Clive Davidson , 1998

Adrian Thompson, who works at the university’s Centre for Computational Neuroscience and Robotics, came up with the idea of self-designing circuits while thinking about building neural network chips. A graduate in microelectronics, he joined the centre four years ago to pursue a PhD in neural networks and robotics.
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To get the experiment started, he created an initial population of 50 random circuit designs coded as binary strings. The genetic algorithm, running on a standard PC, downloaded each design to the Field Programmable Gate Arrays (FPGA) and tested it with the two tones generated by the PC’s sound card. At first there was almost no evidence of any ability to discriminate between the two tones, so the genetic algorithm simply selected circuits which did not appear to behave entirely randomly. The fittest circuit in the first generation was one that output a steady five-volt signal no matter which tone it heard.

By generation 220 there was some sign of improvement. The fittest circuit could produce an output that mimicked the input – wave forms that corresponded to the 1KHz or 10KHz tones – but not a steady zero or five-volt output.

By generation 650, some evolved circuits gave a steady output to one tone but not the other. It took almost another 1,000 generations to find circuits that could give approximately the right output and another 1,000 to get accurate results. However, there were still some glitches in the results and it took until generation 4,100 for these to disappear. The genetic algorithm was allowed to run for a further 1,000 generations but there were no further changes.

See Adrian Thompson’s home page (Department of Informatics, University of Sussex) for more on evolutionary electronics. Such as Scrubbing away transients and Jiggling around the permanent: Long survival of FPGA systems through evolutionary self-repair:

Mission operation is never interrupted. The repair circuitry is sufficiently small that a pair could mutually repair each other. A minimal evolutionary algorithm is used during permanent fault self-repair. Reliability analysis of the studied case shows the system has a 0.99 probability of surviving 17 times the mean time to local permanent fault arrival. Such a system would be 0.99 probable to survive 100 years with one fault every 6 years.

Very cool.

Related: Evolutionary Design – Invention Machine – Evo-Devo

Simple Webcasts on Evolution and Genes

Webcast from 23andme on human evolution. Continued: What are genes?, What are SNPs? (Single Nucleotide Polymorphisms), Where do your genes come from? and What is phenotype?. These webcasts provide an easy to understand overview. Sergey Brin, Google co-founder and husband of 23andme co-founder Anne Wojcicki. People have 23 pairs of chromosomes.

What are SNPs?:

For a variation to be considered a SNP, it must occur in at least 1% of the population. SNPs, which make up about 90% of all human genetic variation, occur every 100 to 300 bases along the 3-billion-base human genome.
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SNPs do not cause disease, but they can help determine the likelihood that someone will develop a particular illness. One of the genes associated with Alzheimer’s disease, apolipoprotein E or ApoE, is a good example of how SNPs affect disease development. ApoE contains two SNPs that result in three possible alleles for this gene: E2, E3, and E4. Each allele differs by one DNA base, and the protein product of each gene differs by one amino acid.

Single-Celled Giant Provides New Early-Evolution Perspective

Discovery of Giant Roaming Deep Sea Protist Provides New Perspective on Animal Evolution
Biologist Mikhail “Misha” Matz and his colleagues recently discovered the grape-sized protists and their complex tracks on the ocean floor near the Bahamas. DNA analysis confirmed that the giant protist found by Matz and his colleagues in the Bahamas is Gromia sphaerica, a species previously known only from the Arabian Sea.

Matz says the protists probably move by sending leg-like extensions, called pseudopodia, out of their cells in all directions. The pseudopodia then grab onto mud in one direction and the organism rolls that way, leaving a track. Hr says the giant protists’ bubble-like body design is probably one of the planet’s oldest macroscopic body designs, which may have existed for 1.8 billion years.

“I personally think now that the whole Precambrian may have been exclusively the reign of protists,” says Matz. “Our observations open up this possible way of interpreting the Precambrian fossil record.”

He says the appearance of all the animal body plans during the Cambrian explosion might not just be an artifact of the fossil record. There are likely other mechanisms that explain the burst-like origin of diverse multicellular life forms.

Single-Celled Giant Upends Early Evolution

Slowly rolling across the ocean floor, a humble single-celled creature is poised to revolutionize our understanding of how complex life evolved on Earth.

A distant relative of microscopic amoebas, the grape-sized Gromia sphaerica was discovered once before, lying motionless at the bottom of the Arabian Sea. But when Mikhail Matz of the University of Texas at Austin and a group of researchers stumbled across a group of G. sphaerica off the coast of the Bahamas, the creatures were leaving trails behind them up to 50 centimeters (20 inches) long in the mud.

The trouble is, single-celled critters aren’t supposed to be able to leave trails. The oldest fossils of animal trails, called ‘trace fossils’, date to around 580 million years ago, and paleontologists always figured they must have been made by multicellular animals with complex, symmetrical bodies.

The Fall of Spore

image from Spore game

The hype for Spore as it was being developed was grand, and I was intrigued. Unfortunately the compromises I have read about have been disappointing. Seed has written about the development of the game in The Creation Simulation

This was Spore’s central problem: Could the game be both scientifically accurate and fun? The prototyping teams were becoming lost in their scientific interests.
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Spore’s decision”‰—”‰to preserve the illusion of life at the expense of the actual facts of life”‰—”‰made for some substantial casualties. First to go in the cute-versus-science war were the extreme ends of the scale”‰—”‰galaxy formation and origins of life simulation”‰—”‰dismissed as being too abstract and dissipated. Next, small and then big laws were shattered and remade. Wright’s determination to represent faster-than-light travel as impossible crumbled in the face of making the spacefaring section of the game enjoyable. Evolution, despite his staunch Darwinism, became a massively telescoped process that depended on the external, deliberate interventions of the players. And so, instead of becoming the ultimate science project, Spore gradually became the ultimate game.

The snag is that Spore didn’t just jettison half its science”‰—”‰it replaced it with systems and ideas that run the risk of being actively misleading. Scientists brought in to evaluate the game for potential education projects recoiled as it became increasingly evident that the game broke many more scientific laws than it obeyed.

I can understand this process and even admit it might be the right choice for those involved. I am just disappointed we don’t have what was imagined (and hyped) early on – a great, fun, learning environment to enjoy and learn from.

The game has an amazingly low 1 1/2 star rating on Amazon with 3,121 reviews (I have never seen anything so popular so disliked on Amazon). Some of the disappointment is in the compromises made but I know a bunch is for the hated digital rights management DRM used by Spore.

Vampire Moth Discovered

Entomologist Jennifer Zaspel at the University of Florida in Gainesville said the discovery suggests the moth population could be on an “evolutionary trajectory” away from other C. thalictri populations.

In January, she will compare the Russian population’s DNA to that of other populations and other species to confirm her suspicions. “Based on geography, based on behavior, and based on a phenotypic variation we saw in the wing pattern, we can speculate that this represents something different, something new,” Zaspel said.
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Only male moths exhibit blood feeding, she noted, raising the possibility that as in some species of butterflies and other moths, the Russian moths do it to pass on salt to females during copulation.

“There is no evidence it prolongs the life of the male, or anything like that,” she said. “So we suspect that it is probably going to the female.” The sexual gift, she said, would provide a nutritional boost to young larvae that feed on leaf-rich, but sodium-poor, diets.

MicroRNAs Emerged Early in Evolution

New Research Shows MicroRNAs Emerged Early in Evolution

“MicroRNAs have been available to regulate and shape gene expression as far back as we can go in animal evolution—they might even predate animals,” says Bartel, a leader in the discovery and functional study of microRNAs. “They might have helped to usher in the era of multi-cellular animal life.”

First discovered in 1993, microRNAs are strands of RNA that are 21-24 nucleotides in length. They dampen gene expression by intercepting messenger RNA before it can turn the cellular crank that translates a gene into a protein. Earlier, Bartel’s research team showed that each microRNA can regulate the expression of hundreds of genes.

The ability of microRNAs to silence gene expression likely evolved from a more ancient defense against viruses, bacteria, and other mobile genetic elements that can mutate host DNA.
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The scientists determined that the starlet sea anemone has both microRNAs and piRNAs. In addition, the anemone makes proteins resembling those that interact with these small RNAs in humans. Both types of small RNA were also found in the sponge. The third target of their search, Trichoplax, did not contain any microRNAs, though Bartel suspects they may have existed in ancestral forms and later disappeared.

Church of England Sees Wisdom in Understanding Evolution

Good religion needs good science by Rev Dr Malcolm Brown, Director of Mission and Public Affairs

When a big new idea emerges which changes the way people look at the world, it’s easy to feel that every old idea, every certainty, is under attack and then to do battle against the new insights. The church made that mistake with Galileo’s astronomy, and has since realised its error. Some church people did it again in the 1860s with Charles Darwin’s theory of natural selection.
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Subsequent generations have built on Darwin’s work but have not significantly undermined his fundamental theory of natural selection. There is nothing here that contradicts Christian teaching. Jesus himself invited people to observe the world around them and to reason from what they saw to an understanding of the nature of God (Matthew 6: 25–33). Christian theologians throughout the centuries have sought knowledge of the world and knowledge of God. For Thomas Aquinas there was no such thing as science versus religion; both existed in the same sphere and to the same end, the glory of God.
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Charles Darwin: 200 years from your birth, the Church of England owes you an apology for misunderstanding you and, by getting our first reaction wrong, encouraging others to misunderstand you still. We try to practice the old virtues of ‘faith seeking understanding’ and hope that makes some amends. But the struggle for your reputation is not over yet, and the problem is not just your religious opponents but those who falsely claim you in support of their own interests. Good religion needs to work constructively with good science – and I dare to suggest that the opposite may be true as well.