domingo, 30 de noviembre de 2008

Videos de Grey Thumb

http://www.greythumb.org/site/index.php?page=meeting-videos

Una sociedad global para intercambiar ideas sobre vida artificial y tecnología basada en procesos evolutivos.
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sábado, 29 de noviembre de 2008

Selección del Complexity Digest - Noviembre

Elysia chlorotica, the solar-powered sea slug, is about 3 cm long (Image: PNAS)

Solar-Powered Sea Slug Harnesses Stolen Plant Genes, New Scientist

Excerpts:

Young E. chlorotica fed with algae for two weeks, could survive for the rest of their year-long lives without eating, Rumpho found in earlier work.

But a mystery remained. Chloroplasts only contain enough DNA to encode about 10% of the proteins needed to keep themselves running. The other necessary genes are found in the algae's nuclear DNA. "So the question has always been, how do they continue to function in an animal cell missing all of these proteins," says Rumpho.

Darwin 200: The Needs Of The Many, Nature

Excerpts: Yet group selection - the idea that evolution can choose between groups, not just the individuals that make them up - has a higher profile today than at any time since its apparent banishment from mainstream evolutionary theory. And it gets better press, too. This is in part owing to the efforts of David Sloan Wilson, of Binghamton University in New York, who argues that the dismissal of group selection was a major historical error that needs to be rectified. And it does not hurt that he has been joined by Edward O. Wilson, the great naturalist and authority on social insects.

Darwin 200: Beneath The Surface, Nature

Excerpts: You might think that once evolution has found one way to get something done, it will stick with it. But similar physical forms can hide radically different wiring, (...).

Tunicates - also known as sea squirts - are humans' closest invertebrate cousins. They have tadpole-like larvae that closely resemble miniature vertebrate embryos and so were expected to build their bodies in the same way. But they don't. (..) It's as if you had found a car in which components of the engine were scattered all over the back seat - but the car still worked.

Genetics: Quick Change, Nature

Excerpts: By mutating just two genes, researchers in Belgium have turned a slender annual plant (...) into a bushy, woody perennial (...).

Variation In Evolutionary Patterns Across The Geographic Range Of A Fossil Bivalve, Science

Excerpts: Within a fossil bivalve genus, evolution tended to occur as a random walk at the highest latitudes and to be in stasis mode in deep marine environments.

The fossil record is the only direct source of data for studying modes (patterns) and rates of morphological change over long periods of time. Determining modes and rates is important for understanding macroevolutionary processes, but just how modes and rates vary within a taxon, and why, remain largely unaddressed. We examined patterns of morphological change in the shell of the Mesozoic marine bivalve genus Buchia over its geographic and temporal range.

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miércoles, 19 de noviembre de 2008

Selección del Complexity Digest - Octubre y Noviembre

DNA Chunks, Chimps And Humans: Marks Of Differences Between Human And Chimp Genomes, Innovations-report

Excerpts: Researchers have carried out the largest study of differences between human and chimpanzee genomes, identifying regions that have been duplicated or lost during evolution of the two lineages. (...) "By looking at only one 'reference' sequence for human or chimpanzee, as has been done previously, it is not possible to tell which differences occur only among individual chimpanzees or humans and which are differences between the two species. (...) Rather than examining single-letter differences in the genomes (so-called SNPs), the researchers looked at copy number variation (CNV) - the gain or loss of regions of DNA. (...)


Human Genes Are Multitaskers - Up To 94% Of Human Genes Can Generate Different Products., Nature

Excerpts: Most genes are made from sections of DNA found at different locations along a strand. The data encoded in these fragments are joined together into a functional messenger RNA (mRNA) molecule that can be used as a template to generate proteins.

But researchers have found that the same gene can be assembled in different ways, sometimes leaving out a piece, for example, or including a bit of the intervening DNA sequence.

(...)

This process, called alternative splicing, can produce mRNA molecules and proteins with dramatically different functions, despite being formed from the same gene.


Being Human: Language: A Social History Of Words, Nature

Excerpts: The evolution of language probably occurred in concert with the evolution of many of the other traits we associate with being human, such as the ability to fashion tools or a strong propensity to learn. If this is true, it suggests that we shouldn't be trying to understand one characteristically human trait in isolation from the others. Moreover, instead of the brain being a collection of separate modules, each dedicated to a specific trait or capacity, humans are likely to have a complex cognitive architecture that is highly interconnected on multiple levels.


Being Human: Religion: Bound To Believe? Nature

Excerpts: Is religion a product of our evolution? The very question makes many people, religious or otherwise, cringe, although for different reasons. Some people of faith fear that an understanding of the processes underlying belief could undermine it. Others worry that what is shown to be part of our evolutionary heritage will be interpreted as good, true, necessary or inevitable. Still others, many scientists included, simply dismiss the whole issue, seeing religion as childish, dangerous nonsense.


How Evolution Learns From Past Environments To Adapt To New Environments, ScienceDaily

Excerpts: The evolution of novel characteristics within organisms can be enhanced when environments change in a systematic manner, according to a new study (...) suggest that in environments that vary over time in a non-random way, evolution can learn the rules of the environment and develop organisms that can readily generate novel useful traits with only a few mutations. (...) The ability to generate novelty is one of the main mysteries in evolutionary theory. (...) began with the observation that environments in nature seemingly vary according to common rules or regularities. They proposed that organisms can learn how previous environments changed, and then use this information (...).


Camouflage And Visual Perception, Phil. Tran. Biol. Sc.

Excerpts: How does an animal conceal itself from visual detection by other animals? This review paper seeks to identify general principles that may apply in this broad area. It considers mechanisms of visual encoding, of grouping and object encoding, and of search. In most cases, the evidence base comes from studies of humans or species whose vision approximates to that of humans. The effort is hampered by a relatively sparse literature on visual function in natural environments and with complex foraging tasks. (...) Finally, the paper considers how we may understand the processes of search for complex targets in complex scenes. (...)

  • Source: Review. Camouflage And Visual Perception, T. Troscianko, C. P. Benton, P. G. Lovell, D. J. Tolhurst, Z. Pizlo, DOI: 10.1098/rstb.2008.0218, Philosophical Transactions: Biological Sciences, 2008/11/06

Animal Behaviour: Idle Ants, Nature

Excerpts: Genetic tests showed that cheaters, although closely related to their nest-mates, are genetically distinct. They also revealed the same cheater lineage in more than one nest, suggesting that it can spread between colonies, and leading the researchers to describe the cheats as a transmissible 'social cancer' that has evolved to exploit the cooperative behaviour of the majority.


Visions Of Evolution: Self-Organization Proposes What Natural Selection Disposes, Biol. Theor.

Excerpts: This article reviews the seven "visions" of evolution (...) concluding that each posited relationship between natural selection and self-organization has suited different aims and approaches. (...) we show that these seven viewpoints may be collapsed into three fundamentally different ones: (1) natural selection drives evolution; (2) self-organization drives evolution; and (3) natural selection and self-organization are complementary aspects of the evolutionary process. We then argue that these three approaches are not mutually exclusive, since each may apply to different stages of development of different systems. What emerges from our discussion is a more encompassing view: that self-organization proposes what natural selection disposes.


Development Puts An End To Evolution Of Endless Forms, ScienceDaily

Excerpts: Researchers have put forward a simple model of development and gene regulation that is capable of explaining patterns observed in the distribution of morphologies and body plans (or, more generally, phenotypes). (...) Nature truly displays a bewildering variety of shapes and forms. Yet, with all its magnificence, this diversity still represents only a tiny fraction of the endless 'space' of possibilities, and observed phenotypes actually occupy only small, dense patches in the abstract phenotypic space. Borenstein and Krakauer demonstrate that the sparseness of variety in nature can be attributed to the interactions between multiple genes and genetic controls involved in the development of organisms (...).


The Relevance Of Brain Evolution For The Biomedical Sciences, Biol. Lett.

Excerpt: Most biomedical neuroscientists realize the importance of the study of brain evolution to help them understand the differences and similarities between their animal model of choice and the human brains in which they are ultimately interested. Many think of evolution as a linear process, going from simpler brains, as those of rats, to more complex ones, as those of humans. However, in reality, every extant species' brain has undergone as long a period of evolution as has the human brain, and each brain has its own species-specific adaptations. By understanding the variety of existing brain types, we can more accurately reconstruct the brains (...).


Mapping A Clan Of Mobile Selfish Genes, Innovations-report

Excerpt: Much of human DNA is the genetic equivalent of e-mail spam: short repeated sequences that have no obvious function other than making more of themselves. After starting out in our primate ancestors 65 million years ago, one type of repetitive DNA called an Alu retrotransposon now takes up 10 percent of our genome, with about one million copies. Roughly every 20th newborn baby has a new Alu retrotransposon somewhere in its DNA, scientists have estimated. As mutations gradually blur the features of older Alu elements, some become unable to make copies of themselves. (...)


Stone Age Innovation Out Of Africa, Science News

Excerpts: Technological revolutions rocked our world long before the information age. Between 80,000 and 60,000 years ago, it was spurts of innovative toolmaking, rather than extreme climate changes, in southern Africa's Stone Age cultures that heralded a human exodus out of Africa, a new investigation suggests.

Environmental changes in southern Africa, including those brought on by a massive volcanic eruption in Sumatra around 74,000 years ago, played a secondary role at best in instigating ancient cultural advances and intercontinental migrations, (...). Other researchers regard ancient climate fluctuations as key motivators of human movement out of Africa.


Ages For The Middle Stone Age Of Southern Africa: Implications For Human Behavior And Dispersal, Science

Excerpts: Dating of the first use of symbols and jewelry in South Africa shows that the emergence of modern human behavior was not influenced by just environmental factors.

The expansion of modern human populations in Africa 80,000 to 60,000 years ago and their initial exodus out of Africa have been tentatively linked to two phases of technological and behavioral innovation within the Middle Stone Age of southern Africa¡Xthe Still Bay and Howieson's Poort industries¡Xthat are associated with early evidence for symbols and personal ornaments. Establishing the correct sequence of events, however, has been hampered by inadequate chronologies.


The Iceman's Mysterious Genetic Past, Science News

Excerpts: Further genetic studies of modern Europeans might identify some who belong to what Rollo's group has dubbed "Oetzi's branch."

"Through the analysis of a complete mitochondrial genome in a particularly well-preserved body, we have obtained evidence of a significant genetic difference between present-day Europeans and a prehistoric human, despite the fact that the Iceman is only about 5,000 years old," Rollo says.


No Evidence For An Evolutionary Trade-Off Between Learning And Immunity In A Social Insect, Biol. Lett.

Excerpt: The immune response affects learning and memory in insects. Given this and the known fitness costs of both the immune system and learning, does an evolutionary trade-off exist between these two systems? We tested this by measuring the learning ability of 12 bumble-bee (...). We then tested their immune response using the zone of inhibition assay. We found a positive relationship between colony learning performance and immune response, that is, fast-learning colonies also show high levels of antimicrobial activity. We conclude that there is no a priori reason to demand an evolutionary relationship between two traits that are linked physiologically.


Evolutionary Biology: Small Regulatory RNAs Pitch In, Nature

Excerpts: How did organismal complexity evolve at a cellular level, and how does a genome encode it? The answer might lie in differences, not in the number of genes an organism has, but rather in the regulation of gene expression.

It is commonly believed that complex organisms arose from simple ones. Yet analyses of genomes and of their transcribed genes in various organisms reveal that, as far as protein-coding genes are concerned, the repertoire of a sea anemone - a rather simple, evolutionarily basal animal - is almost as complex as that of a human.


Experimental Evidence For Spatial Self-Organization And Its Emergent Effects In Mussel Bed Ecosystems, Science

Excerpts: Spatial self-organization is the main theoretical explanation for the global occurrence of regular or otherwise coherent spatial patterns in ecosystems. Using mussel beds as a model ecosystem, we provide an experimental demonstration of spatial self-organization. Under homogeneous laboratory conditions, mussels developed regular patterns, similar to those in the field. An individual-based model derived from our experiments showed that interactions between individuals explained the observed patterns.


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viernes, 3 de octubre de 2008

"Mauro le compraba Neurofosfato Escay lo que era una idiotez, y también Hierro Quina Bisleri, cosas que se leen en las revistas y se les toma confianza"


Las puertas del cielo
J. Cortázar
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jueves, 2 de octubre de 2008

Requiem para un Neanderthal

Recuerdo las reconstrucciones de los hombres de Neanderthal que disfrutaba en mi infancia. El cavernícola tosco, bestial y enteramente instintivo en su comportamiento. Era muy difícil concebir una convivencia o un trato con este tipo de personas. Con el paso del tiempo, las idiosincracias y el reconocimiento de algunas subjetividades (sapiens, no neanderthales) la comunidad científica ahora piensa que este grupo de humanos pudo haber sido mucho mas parecido al nuestro, por lo menos en algunos refinamientos congnitivo-culturales.
Raul Alzogaray me acercó este vínculo a una nota de National Geographic Magazine revisando un poco los últimos días de los Neanderthales es su distribución mas occidental, la península ibérica.

Foto: Ama de casa neanderthal (probablemente) desesperada

http://ngm.nationalgeographic.com/2008/10/neanderthals/hall-text


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viernes, 12 de septiembre de 2008

Selección del Complexity Digest - Septiembre

New Ant Species Found, Science News

Excerpts:

One weird ant suggests lost world of ancient ants living underground. (...)

Its DNA may be even more interesting. Genetic analysis puts the new ant so far from other species that it deserves its own subfamily, Martialinae, (...).

This newly discovered ant species, with mouthparts like forceps and no eyes, may come from the most ancient known lineage of living ants. Credit: Rabeling and M. Verhaagh



Paleoanthropology: Brainy Babies And Risky Births For Neandertals, Science

Excerpts: As adults, the extinct Neandertals had brains and bodies larger than those of living people. But little has been known about their early brain development because few fossils have been found of Neandertal newborns or female pelves. A 1990 study of 10 Neandertal fossils between the ages of 2 and 10 found that their brain volumes were as large as those of modern humans. But the new study uses "amazing specimens" to provide the first data on infants, (...).


Evolution: Dynamics Of Body Size Evolution, Science

Excerpts: Is bigger better? Does climate affect size? The processes controlling body size evolution remain unclear.

Body size is one of the simplest organismic traits one can measure, yet it correlates with almost every aspect of the biology of a species, from physiology and life history to ecology. So, not surprisingly, biologists have long been interested in understanding how body size evolves. Two things are obvious when one looks at the distribution of body sizes of species within large groups: The sizes span multiple orders of magnitude, and species are not distributed uniformly within this range.


The Evolution Of Superstitious And Superstition-Like Behaviour, Proc. Biol. Sc.

Excerpts: Superstitious behaviours, which arise through the incorrect assignment of cause and effect, receive considerable attention in psychology and popular culture. Perhaps owing to their seeming irrationality, however, they receive little attention in evolutionary biology. Here we develop a simple model to define the condition under which natural selection will favour assigning causality between two events. This leads to an intuitive inequality (...) that shows that natural selection can favour strategies that lead to frequent errors in assessment (...). (...) We conclude that behaviours which are, or appear, superstitious are an inevitable feature of adaptive behaviour in all organisms, including ourselves.


Anthropologists Develop New Approach To Explain Religious Behavior, ScienceDaily

Excerpts: Without a way to measure religious beliefs, anthropologists have had difficulty studying religion. Now, two anthropologists from the University of Missouri and Arizona State University have developed a new approach to study religion by focusing on verbal communication, an identifiable behavior, instead of speculating about alleged beliefs in the supernatural that cannot actually be identified. (...) "We noticed that communicating acceptance of a supernatural claim tends to promote cooperative social relationships. This communication demonstrates a willingness to accept, without skepticism, the influence of the speaker in a way similar to a child's acceptance of the influence of a parent." (...)

Source: Anthropologists Develop New Approach To Explain Religious Behavior, ScienceDaily & University of Missouri-Columbia, 2008/09/10


Biologists Identify Genes Controlling Rhythmic Plant Growth, ScienceDaily

Excerpts: A team of biologists (...) has identified the genes that enable plants to undergo bursts of rhythmic growth at night and allow them to compete when their leaves are shaded by other plants. The researchers report (...) that these genes control the complex interplay of plant growth hormones, plant light sensors and circadian rhythms that permit plants to undergo rhythmic growth spurts at specific times of the day or year in response to varying levels of light and other environmental conditions. Their discovery (...) could eventually allow scientists to design crops that can grow substantially faster and produce more food than the most productive varieties today. (...)


Primordial Fish Had Rudimentary Fingers, PhysOrg.com

Excerpts: Tetrapods, the first four-legged land animals, are regarded as the first organisms that had fingers and toes. Now researchers at Uppsala University can show that this is wrong. Using medical x-rays, they found rudiments of fingers in the fins in fossil Panderichthys, the "transitional animal," which indicates that rudimentary fingers developed considerably earlier than was previously thought.

Our fish ancestors evolved into the first four-legged animals, tetrapods, 380 million years ago. They are the forerunners of all birds, mammals, crustaceans, and batrachians. Since limbs and their fingers are so important to evolution, researchers have long wondered whether they appeared for the first time in tetrapods, or whether they had evolved from elements that already existed in their fish ancestors.


Biological Theory: Postmodern Evolution?, Nature

Excerpts: Over dinner at the meeting's end, Pigliucci expresses his hope of "moving from a gene-centric view of causality in evolution to a pluralist, multilevel causality". Postmodernists in the humanities call this 'decentering', and they are all for it. Over the course of the meeting, it's fairly clear that the means to this pluralist end are being sought through mixing and matching neglected ideas and old problems from biology's past with the latest experimental and analytical techniques.


Network Scaling Reveals Consistent Fractal Pattern In Hierarchical Mammalian Societies, Biol. Lett.

Excerpt: Recent studies have demonstrated that human societies are hierarchically structured with a consistent scaling ratio across successive layers of the social network; each layer of the network is between three and four times the size of the preceding (smaller) grouping level. Here we show that similar relationships hold for four mammalian taxa living in multi-level social systems. For elephant (Loxodonta africana), gelada (Theropithecus gelada) and hamadryas (Papio hamadryas hamadryas) baboon, successive layers of social organization have a scaling ratio of almost exactly 3, indicating that such branching ratios may be a consistent feature of all hierarchically structured societies. (...)

Scientists Develop New Computational Method To Investigate Origin Of Life, ScienceDaily

Excerpts: Scientists at Penn State have developed a new computational method that they say will help them to understand how life began on Earth. The team's method has the potential to trace the evolutionary histories of proteins all the way back to either cells or viruses, thus settling the debate once and for all over which of these life forms came first. "We have just begun to tap the potential power of this method," said (...). "We believe, if it is possible at all, that it is within our grasp to determine whether viruses evolved from cells or vice-versa." (...)

Multimodal Warning Signals For A Multiple Predator World, Nature

Excerpts: During spring, when birds are active and bats less so, we found that tiger moths did not produce ultrasonic clicks. Throughout both spring and summer, tiger moths most active during the day were visually conspicuous. Those species emerging later in the season produced ultrasonic clicks; those that were most nocturnal were visually cryptic. Our results indicate that selective pressures from multiple predator classes have distinct roles in the evolution of multimodal warning displays now effective against a single predator class.

Big Data: Wikiomics, Nature

Excerpts: Pioneering biologists are trying to use wiki-type web pages to manage and interpret data, reports Mitch Waldrop. But will the wider research community go along with the experiment? (...)

Scientists write review articles and textbooks to make sense of it all. But it's still not enough.

Hence the proliferation of wikis, which have the potential to vastly multiply the number of annotators and bring in the most interested expertise: "The best people to do annotation are the researchers in the laboratories, the people who are producing this knowledge in the first place,(...)."

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domingo, 31 de agosto de 2008

El fino arte de adivinar que terminarás opinando

Puede pasar que caminando por la calle, el dia menos pensado nos interceptan para preguntarnos que opinamos sobre tal o cual preocupación de los medios en ese dia particular y terminemos ilustrando unos segundos del noticiero de esa misma noche. Siempre con la sensación de que nos vemos horrendos o sin acostumbrarnos nunca a nuestro tono de voz cuando los escuchamos grabado y no desde los ecos de nuestra cabeza.
Científicos e investigadores son frecuentemente buscados por los mismos periodistas pero directamente en sus lugares de trabajo e interpelados sobre los mas variopintos temas. Lo distinto de esta situación es que se los consulta como autoridades y por lo tanto nuestra opinión tiene otro cariz. A veces de temas que manejas, y muy frecuentemente no. Sabiendo esto está en cada uno lo que dirá, opinará o rehusará contar en cada situación. Finalmente, y suponiendo que se obtuvo una información y opinión válida del tema, está la tiranía de la síntesis y búsqueda de impacto de las redacciones periodísticas que pueden terminar poniendo en boca de los consultados las ideas exactamente opuestas.
No digo que lo que muestro a continuación sea exactamente el caso pero seguro sirve para ver lo que se dice, lo que se pierde y lo que llega. Primero lo que escribí para el diario Perfil que me consultó sobre un movimiento sobre derechos de los simios que estaría cobrando fuerza en España ( las preguntas fueron enviadas por la redacción) y luego la nota tal cual fue publicada.

a) El correo electrónico

Primero quiero decirte que siempre son bienvenidas noticias que propongan reflexiones sobre la ética, la forma en que los humanos se relacionan con el resto de la naturaleza y los límites que debemos imponernos (o no).

¿Cuáles deberían ser los límites –si los hay– en la investigación biomédica con animales?

Esa es una pregunta realmente difícil de contestar. Por un lado, involucra determinar cual es la relación de uno con el animal objeto de manipulación y esa es una postura filosófica. Una postura donde los seres vivos “no humanos” son considerados mas como objetos que como seres sensibles va a afirmar que no hay límite teórico para experimentar con animales en pos del beneficio humano. Evidentemente se puede objetar contra este tipo de accionar, tal cual lo hacen los grupos de protección de los animales.
Por otro lado, el accionar científico no es algo independiente de la sociedad en donde se produce. Por lo tanto es la ética y la moral de nuestra cultura la que determinará los límites. Y si dudamos al respecto es porque no es un tema plenamente debatido. En la medida que esta pregunta se la hagan a biólogos (en la UBA, en ningún momento de nuestra formación se incluye Ética) y médicos exclusivamente y no se llame a gente formada en filosofía y ética no vamos a conseguir una respuesta acabada.

España estaría por aprobar una legislación que prohíbe cualquier tipo de investigación con homínidos, ¿qué contras tendría para la ciencia la imposición de esta limitación?

Así planteado los únicos afectados son los grupos españoles de investigaciones biomédicas con modelos homínidos y desconozco pero me atrevo a decir que no deben ser más que un par. Si esta medida termina siendo por toda la comunidad científica internacional entonces se deberá recurrir a métodos más indirectos, modelados teóricos o modelos biológicos más lejanamente emparentados de los humanos. Entiendo por ejemplo que el macaco Rhesus (Macaca mulatta) es un mono que queda afuera de esta discusión y es muy utilizado en los laboratorios.

Los movimientos que proponen que los simios deben gozar de los mismos derechos y garantías legales que los humanos, hablan de "especieísmo", en lugar de racismo, en tanto la investigación científica que experimenta con animales partiría del prejuicio de considerar como inferior a cualquier otra especie. ¿Tiene sentido el concepto? ¿Está de acuerdo?

Ambas posturas son falaces y antropocéntricas y solo discuten donde trazar la línea de “humanidad” y que queda excluido. No me parece que para proteger especies debamos “humanizarlas”. En vez de enumerar todos los aspectos que compartimos con los otros grandes simios deberíamos apreciar y proteger las diferencias. Y si las diferencias reside la riqueza de la biodiversidad entonces no debemos discutir sobre grandes simios sino sobre nuestro trato a todo el conjunto de seres vivos.
Una de las primeras lecciones del estudiante de Evolución es que no hay seres inferiores o superiores. Todos los organismos vivos en la actualidad descienden de un antepasado común y por lo tanto pertenecen a grupos que vienen evolucionando desde entonces, en ese sentido son igual de exitosos. Por otro lado, las adaptaciones no aseguran la perpetuación eterna y por eso la probabilidad de extinción siempre existe para todas las especies. En eso tampoco hay organismos superiores o inferiores. Y si bien hay seres más o menos complejos esto tampoco es una cualidad que se refleje en una superioridad intrínseca. Desde la biología evolutiva no hay un criterio para determinar en que sentido una gacela es “mejor” que su flora intestinal o el pasto que come.


b) La nota en el diario

http://www.diarioperfil.com.ar/edimp/0290/articulo.php?art=9404&ed=0290#sigue
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sábado, 23 de agosto de 2008

Selección del Complexity Digest - Agosto

Birds Are Tracking Climate Warming, But Not Fast Enough, Proc. Biol. Sc.

Excerpt: Range shifts of many species are now documented as a response to global warming. But whether these observed changes are occurring fast enough remains uncertain and hardly quantifiable. Here, we developed a simple framework to measure change in community composition in response to climate warming. This framework is based on a community temperature index (CTI) that directly reflects, for a given species assemblage, the balance between low- and high-temperature dwelling species. Using data from the French breeding bird survey, we first found a strong increase in CTI over the last two decades revealing that birds are rapidly tracking climate warming. (...)

Ecology: A Matter Of Timing, Science

Excerpts: Climate change is causing shifts in the distribution and phenology of many plants and animals. Birds have played a key role in detecting these changes, because long-term data are available on the distribution, migration, and breeding of many species. Studies of the timing of egg laying--a key trait with extensive records dating back half a century for some species--are providing crucial insights into the mechanisms that underlie the response to climate change.
  • Source: Ecology: A Matter Of Timing, Bruce E. Lyon, Alexis S. Chaine, David W. Winkler, DOI: 10.1126/science.1159822, Science : Vol. 321. no. 5892, pp. 1051 - 1052, 08/08/22

Self-Destructive Cooperation Mediated By Phenotypic Noise, Nature

Excerpts: In many biological examples of cooperation, individuals that cooperate cannot benefit from the resulting public good. This is especially clear in cases of self-destructive cooperation, where individuals die when helping others. If self-destructive cooperation is genetically encoded, these genes can only be maintained if they are expressed by just a fraction of their carriers, whereas the other fraction benefits from the public good. One mechanism that can mediate this differentiation into two phenotypically different sub-populations is phenotypic noise. Here we show that noisy expression of self-destructive cooperation can evolve if individuals that have a higher probability for self-destruction have, on average, access to larger public goods.

Exploding Chromosomes Fuel Research About Evolution, Innovations-report

Excerpt: Human cells somehow squeeze two meters of double-stranded DNA into the space of a typical chromosome, a package 10,000 times smaller than the volume of genetic material it contains. Now research into single-celled, aquatic algae called dinoflagellates is showing that these and related organisms may have evolved more than one way to achieve this feat of genetic packing. Even so, the evolution of chromosomes in dinoflagellates, humans and other mammals seem to share a common biochemical basis, (...). Packing the whole length of DNA into tiny chromosomes is problematic because DNA carries a negative charge that, unless neutralized, prevents any attempt at folding (...).

Genomics: 'Simple' Animal's Genome Proves Unexpectedly Complex, Science

Excerpts: Aptly named "sticky hairy plate," Trichoplax adhaerens barely qualifies as an animal. About 1 millimeter long and covered with cilia, this flat marine organism lacks a stomach, muscles, nerves, and gonads, even a head. It glides along like an amoeba, its lower layer of cells releasing enzymes that digest algae beneath its ever-changing body, and it reproduces by splitting or budding off progeny. Yet this animal's genome looks surprisingly like ours, says Daniel Rokhsar, an evolutionary biologist at the University of California, Berkeley (UCB) and the U.S. Department of Energy Joint Genome Institute in Walnut Creek, California. Its 98 million DNA base pairs include many of the genes responsible for guiding the development of other animals' complex shapes and organs, he and his colleagues report in the 21 August issue of Nature.


Animal Behaviour: Crowd Control, Nature

Excerpts: Many researchers would expect parasitic infection rates to increase as groups of animals get bigger and more hosts are available. Contrary to this, researchers reveal that as groups of red colobus monkeys (Procolobus rufomitratus) get larger, they have fewer parasites.

Tamaini Snaith at McGill University in Montreal, Canada, and her colleagues made the discovery while studying the monkeys in Uganda. They tested faeces for parasites and monitored group dynamics. The researchers noticed that large groups tended to spread out more than smaller ones, and suggest that this could lower infection rates.

Evolutionary Biology: Deciphering the Genetics of Evolution, Science

Excerpts: Powerful personalities in evolutionary biology have been tussling over how the genome changes to set the stage for evolution. (...)

Early suggestions that gene regulation could be important to evolution came in the 1970s from work by bacterial geneticists showing a link between gene expression and enzyme activity in bacteria. About the same time, Allan Wilson and Mary-Claire King of the University of California, Berkeley, concluded that genes and proteins of chimps and humans are so similar that our bipedal, hairless existence must be the product of changes in when, where, and to what degree those genes and proteins come into play. (...).


Evolution of Evolvability in Gene Regulatory Networks, PLoS Comput Biol

Excerpt: A cell receives signals both from its internal and external environment and responds by changing the expression of genes. In this manner the cell adjusts to heat, osmotic pressures and other circumstances during its lifetime. Over long timescales, the network of interacting genes and its regulatory actions also undergo evolutionary adaptation. Yet how do such networks evolve and become adapted?
In this paper we describe the study of a simple model of gene regulatory networks, focusing solely on evolutionary adaptation most fit.

Astronomy: Planetary System Formation, Science

Excerpts: To date, 307 extrasolar planets have been discovered and 29 multipleplanet systems have been identified (1, 2). The masses of the planets range from a few Earth masses up to several Jupiter masses, with orbital periods ranging from slightly over 1 day to several years. Unlike in our solar system, the orbital eccentricities of the extrasolar gas giant-sized planets may be large.

Do Subatomic Particles Have Free Will?, Science News

Excerpts: If we have free will, so do subatomic particles, mathematicians claim to prove. (...)

They used a pure mathematical argument to show that there is no way the particle can choose spins around every imaginable axis in a way that is consistent with the 1-0-1 rule. Indeed, there is a set of just 33 axes that are enough to force the particle into a paradox. It could choose spins around the first 32 axes that conform with the rule, but for the last, neither 0 nor non-zero would do.


Differential Selection According To The Degree Of Cheating In A Status Signal, Biol. Lett.

Excerpts: The maintenance of honesty in a badge-of-status system is not fully understood, despite numerous empirical and theoretical studies. Our experiment examined the relationship between a status signal and winter survival, and the long-term costs of cheating, by manipulating badge size in male house sparrows, Passer domesticus. The effect of badge-size manipulation on survival was complex owing to the significant interactions between the treatments and original (natural) badge size, and between the treatments and age classes (yearlings and older birds). (...) This indicates that differential selection can act on a trait according to the degree of cheating.

Brain Will Be Battlefield Of Future, Warns US Intelligence Report, Guardian

Excerpts:
On the battlefield, bullets may be replaced with "pharmacological land mines" that release drugs to incapacitate soldiers on contact, while scanners and other electronic devices could be developed to identify suspects from their brain activity and even disrupt their ability to tell lies when questioned, the report says. (...)

The report highlights one electronic technique, called transcranial direct current stimulation, which involves using electrical pulses to interfere with the firing of neurons in the brain and has been shown to delay a person's ability to tell a lie.

Survival Of The Fittest: Even Cancer Cells Follow The Laws Of Evolution, ScienceDaily

Excerpts: Scientists (...) discovered that the underlying process in tumor formation is the same as for life itself-evolution. After analyzing a half million gene mutations, the researchers found that although different gene mutations control different cancer pathways, each pathway was controlled by only one set of gene mutations. This suggests that a molecular "survival of the fittest" scenario plays out in every living creature as gene mutations strive for ultimate survival through cancerous tumors. This finding (...) improves our understanding of how evolution shapes life in all forms, while laying a foundation for new cancer drugs and treatments. (...)

A Blueprint to Regenerate Limbs, Technology review

Excerpts:
Growing limbs: The axolotl salamander is one of the only vertebrates that can regrow entire limbs as an adult. Scientists are now sequencing parts of its unusually large genome in order to understand the genetic basis for this capability.
Credit: Jeramiah Smith
Probing the salamander genome reveals clues to its remarkable ability to regrow damaged limbs and organs. (...)

In order to quickly identify sections of the salamander's genome involved in regeneration, the scientists sequenced genes that were most highly expressed during limb-bud formation and growth. They found that at least 10,000 genes were transcribed during regeneration. Approximately 9,000 of those seem to have related human versions, but there appear to be a few thousand more that don't resemble known genes. "We think many of them are genes that evolved uniquely in salamanders to help with this process," (...).


Slave Ants Rebel, Science News

Excerpts:
Members of a species of ants captured to work as slaves rebel against their captors by destroying the pupae they were enslaved to nurture.
Credit: Alexandra Achenbach/ Ludwig-Maximilians University
Killing sprees by slave nannies could be an overlooked form of resistance, Foitzik suggests. The baby-killing offers any kin in nearby colonies some protection from slave-makers, since the kidnapper queen's offspring make up the raiding parties. Paring back their number cuts back the raiding power. Foitzik proposes that this benefit to kin could drive the evolution of the trait.

"This is evolution to be a bad nanny," (...).

















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