After taking a fresh look at an old fossil, John Flynn, Frick Curator of Paleontology at the American Museum of Natural History, and colleagues determined that the brains of the ancestors of modern Neotropical primates were as small as those of their early fossil simian counterparts in the Old World. This means one of the hallmarks of primate biology, increased brain size, arose independently in isolated groups—the platyrrhines of the Americas and the catarrhines of Africa and Eurasia.
“Primatologists have long suspected that increased encephalization may have arisen at different points in the primate evolutionary tree, but this is the first clear demonstration of independent brain size increase in New and Old World anthropoids,” says Flynn of the paper that appeared in the Museum’s publication Novitates this June. Encephalization is the increase in brain size relative to body size. Animals with large encephalization quotients (E.Q.’s) are those with bigger brains relative to their body size in comparison to the average for an entire group. Most primates and dolphins have high E.Q.’s relative to other mammals, although some primates (especially apes and humans) have higher E.Q.’s than others. … Continue Reading »
New exquisitely preserved fossils from Latvia cast light on a key event in our own evolutionary history, when our ancestors left the water and ventured onto land. Swedish researchers Per Ahlberg and Henning Blom from Uppsala University have reconstructed parts of the animal and explain the transformation in the new issue of Nature.
It has long been known that the first backboned land animals or “tetrapods” - the ancestors of amphibians, reptiles, birds and mammals, including ourselves - evolved from a group of fishes about 370 million years ago during the Devonian period. However, even though scientists had discovered fossils of tetrapod-like fishes and fish-like tetrapods from this period, these were still rather different from each other and did not give a complete picture of the intermediate steps in the transition.
In 2006 the situation changed dramatically with the discovery of an almost perfectly intermediate fish-tetrapod, Tiktaalik, but even so a gap remained between this animal and the earliest true tetrapods (animals with limbs rather than paired fins). Now, new fossils of the extremely primitive tetrapod Ventastega from the Devonian of Latvia cast light on this key phase of the transition.
“Ventastega was first described from fragmentary material in 1994; since then, excavations have produced lots of new superbly preserved fossils, allowing us to reconstruct the whole head, shoulder girdle and part of the pelvis”, says Professor Per Ahlberg at the Department of Physiology and Developmental Biology, Uppsala University.
The recontructions made by Professor Ahlberg and Assistant Professor Henning Blom together with British and Latvian colleagues show that Ventastega was more fish-like than any of its contemporaries, such as Acanthostega. The shape of its skull, and the pattern of teeth in its jaws, are neatly intermediate between those of Tiktaalik and Acanthostega.
“However, the shoulder girdle and pelvis are almost identical to those of Acanthostega, and the shoulder girdle is quite different from that of Tiktaalik (the pelvis of Tiktaalik is unknown), suggesting that the transformation from paired fins to limbs had already occurred. It appears that different parts of the body evolved at different speeds during the transition from water to land”, says Per Ahlberg.
It’s too bad DNA doesn’t really get preserved in fossils. While reading this type of thing though, I can’t help but think how this is just another nail in the coffin for the creationists, such when a new “species” of E. coli recently evolved in the lab. However, even in light of such strong evidence, they still just call it fraudulant, even to the author’s face.
A new discovery by a scientist from The University of Western Ontario provides conclusive evidence which supports decades-old evolutionary doctrines long accepted as fact.
Since renowned British biologist Richard Dawkins (”The God Delusion”) introduced the concept of the ’selfish gene’ in 1976, scientists the world over have hailed the theory as a natural extension to the work of Charles Darwin.
In studying genomes, the word ’selfish’ does not refer to the human-describing adjective of self-centered behavior but rather to the blind tendency of genes wanting to continue their existence into the next generation. Ironically, this ’selfish’ tendency can appear anything but selfish when the gene does move ahead for selfless and even self-sacrificing reasons.
For instance, in the honey bee colony, a complex social breeding system described as a ’super-organism,’ the female worker bees are sterile. The adult queen bee, selected and developed by the worker bees, is left to mate with the male drones.
Because the ’selfish’ gene controlling worker sterility has never been isolated by scientists, the understanding of how reproductive altruism can evolve has been entirely theoretical – until now.
Working with Peter Oxley of the University of Sydney in Australia, Western biology professor Graham Thompson has, for the first time-ever, isolated a region on the honey bee genome that houses this ’selfish’ gene in female workers bees.
This means that the ’selfish’ gene does exist, not just in theory but in reality. “We don’t know exactly which gene it is, but we’re getting close.”
“This basically provides a validation for a huge body of socio-biology,” says Thompson, who adds the completion of Honey Bee Genome Project in 2006 was crucial to this discovery.
Researchers from Uppsala University, Karolinska Institute, and the University of Chicago, have determined that there are hundreds of biological differences between the sexes when it comes to gene expression in the cerebral cortex of humans and other primates. These findings, published June 20th in the open-access journal PLoS Genetics, indicate that some of these differences arose a very long time ago and have been preserved through the evolution of primates. These conserved differences constitute a signature of sex differences in the brain.
More obvious gender differences have been preserved throughout primate evolution; examples include average body size and weight, and genitalia design. This novel study focuses on gene expression within the cerebral cortex – that area of the brain that is involved in such complex functions in humans and other primates as memory, attentiveness, thought processes, and language.
The researchers measured gene expression in the brains of male and female primates from three species: humans, macaques, and marmosets. To measure activity of specific genes, the products of genes (RNA) obtained from the brain of each animal were hybridized to microarrays containing thousands of DNA clones coding for thousands of genes. The authors also investigated DNA sequence differences among primates for genes showing different levels of expression between the sexes.
“Knowledge about gender differences is important for many reasons. For example, this information may be used in the future to calculate medical dosages, as well as for other treatments of diseases or damage to the brain,” says Professor Elena Jazin of Uppsala University.
Lead author Björn Reinius notes that the study does not determine whether these differences in gene expression are in any way functionally significant. Such questions remain to be answered by future studies.
The top three evolution parodies on the top three parody television shows: South Park, Family Guy, and The Simpsons.
South Park
South Park, as usual, is “I’m so much smarter than all you idiots that I can flaunt my total disregard for all social norms… especially intellectualism.” They say “butt sex retard fish squirrel!” L0LZ!1
Yet, South Park is the only one of the three top shows that parodies not the surface debate itself as some cheap ploy for relevance, but how people actually behave and what people actually believe —not what they say.
The gag is: The substance of Mr. Garrison’s opinions are always irrelevant. It’s his zealotry that’s the joke, and zealotry can be about anything.
The scenario could be reversed to the same effect: an atheist zealot could be denouncing religion while begrudgingly subscribing to an institutionally-enforced liberal ideology of tolerance (*cough* academia *cough*). That zealotry would be as equally absurd. And —that’s exactly the plot of the full South Park two-episode plot arc.
In fact, the ultimate gag is that Mr. Garrison and Richard Dawkins so strongly reflect each other’s narcissistic zealotry that when fused in some horrible bout of filthy monkey sex, the greater Garrison-Dawkins achieves world domination. Cartman must sabotage their relationship to save the world from a dystopic future of warring factions of religiously-atheist zealots.
Richard Dawkins on “Go God Go:”
I wouldn’t have minded so much if only it had been in the service of some serious point, but if there was a serious point in there I couldn’t discern it.
South Park, as usual, is the funniest, most relevant, and insightful.
Family Guy
Oh ha ha! The evolution-creationism debate is relevant! So it’s funny! Get it, religious people are stupid and Americans are stupid! Jesus was a pretty cool dude, though. I’d smoke a bowl with Jesus. Oh dude! Did you finish your comm 200 paper for tomorrow? Dude, it’s already like, 2am.
Family Guy: non sequitur, every episode, nothing of lasting substance
Simpsons
No statement, just the animators amusing themselves by paying homage to an old film cliche in The Simpsons’ artistic style. By this season, the message is: we’ve become a cultural icon on the merits of our past work, but we’ve long since sold out, so just let us this one guilty pleasure before we’re reduced to grinding out this week’s episode, OK? For old-time’s sake.
Simpsons: A small gasp of creativity from the genre-making giant too huge to die without a stinking, bloated corpse.
What are the genes implicated in upright walking of humans? The discovery of four families in which some members only walk on all fours (quadrupedality) may help us understand how humans, unlike other primates, are able to walk for long periods on only two legs, a scientist will tell the annual conference of the European Society of Human Genetics tomorrow (Monday 2 June).
The quadrupedal families in Turkey previously attracted attention in 2005, when they were discovered. Now the Turkish team reports that they have found the first gene implicated in quadrupedal locomotion in these families.
Professor Tayfun Ozcelik, of Bilkent University, Ankara, Turkey, and colleagues, studied four unrelated families where some members were affected by the rare quadrupedic condition, Unertan syndrome, which is also associated with imperfect articulation of speech, mental retardation, and defects in the cerebellum, a part of the brain involved in motor control. They found that the affected individuals in two families had mutations in the gene responsible for the expression of very low density lipoprotein receptor (VLDLR), a protein which is known to be critical to the proper functioning of the cerebellum during development.
Although the families lived in isolated villages 200-300 km apart and reported no ancestral relationships, the scientists expected to find a single genetic mutation implicated in the condition. They were surprised to find that this was not the case.
“We carried out genome-wide screening on these families”, said Professor Ozcelik, “and found regions of DNA that were shared by all those family members who walk on all fours. However, we were surprised to find that genes on three different chromosomes are responsible for the condition in four different families.
“In families A and D there were mutations in VLDLR on chromosome 9, and in family B the phenotype maps to chromosome 17 to a region that contains at least 157 genes, and we are still looking for the precise mutation. Neither region appears to be implicated for family C.”
In all cases, the affected individuals were the offspring of consanguineous marriages, which suggests that if they had married outside the family they would not have had the condition. All of them had significant developmental delay in infancy. “Whereas normal infants make the transition to walking on two legs in a relatively short period”, said Professor Ozcelik, “these individuals continued to move on their palms and feet and never walked upright. Although they can stand from a sitting position and maintain this upright position with flexed hips and knees, they virtually never initiate bipedal walking on their own.”
It has been suggested in the past that lack of access to medical care exacerbated the effects of an under-developed cerebellum, and that this led to quadrupedality. “Although it may be true that family B lacked proper medical care, families A and D had consistent access to good medical attention, and both families sought a correction of quadrupedality in their affected children”, said Professor Ozcelik. “Indeed, an unaffected member of family A is a physician, who has been actively involved in the medical interventions. In addition, the parents in family A also discouraged their affected children from walking on all fours, to no avail. We think that social factors are unlikely to be involved in the development of quadrupedal locomotion.”
Mutations causing VLDLR deficiency are also found in Hutterites, a group of Anabaptists who live in colonies of North America. There, however, most of the affected individuals cannot walk at all. The neurological characteristics of the affected members of the Turkish families and the Hutterites seem similar, with the most striking difference being that the Turkish individuals are able to walk on all fours, said the scientists. They hypothesize that the Hutterites may be more profoundly affected due to the deficiency in VLDLR and a neighbouring gene, and therefore lack the motor skills even for quadrupedal locomotion.
Along with brain enlargement, speech, and the ability to make tools, upright walking has long been regarded as one of the key traits that have led to modern humans. Professor Ozcelik’s team have opened a window on how mutations in VLDLR affect brain development and influence gait in humans.
“It will be interesting to see if the VLDLR gene is involved in other types of cerebellar ataxias. In addition, we hope to identify the defective genes associated with quadrupedal locomotion in families B and C”, he says.
While not really practical immediately, it’s an interesting study. I think the title and content are a bit misleading, as there are mutations that disrupt neurological development and a side effect of some of these is quadrupedality. It would almost seem to me that perhaps the brain reverts to a more “primitive” setup and just defaulted to quadrupedality.
Andrew says:
I think that this is misleading, too, so I changed the title a bit. (original title was “genetic mutation linked to walking on all 4s,” which implied some “missing link” gene.
The mutations are various flaws in a lipoprotein receptor which impairs cerebellum development, not all the complex skeletal, muscular, and neurological mutations (and more) plausibly necessary to produce a viable quadruped human. The link-bait here is the “mutation of the missing link,” and that’s an irritating and fundamental misunderstanding about how evolution works that doesn’t need to be perpetuated here.
But what I do think is significant is that this suggests that an advanced cerebellum evolved first, and then the relevant skeletal-muscular changes gradually accumulated to make modern bipedal humans from an already somewhat transitory bipedal/quadrupedal evolutionary state (like primates). Mutations which favor bipedality at the expense of quadrupedality are only an evolutionary advantage once the brain can process the locomotion, something that an advanced cerebellum apparently can do. But, an advanced cerebellum is probably a net advantage (or at least, not a disadvantage) before bipedality. This supports contemporary evolutionary theory.
As we here at Think Gene are Serious Internet Professionals (SIPs), it is my obligation rebuke this video in defense of Big Science. However, the fact is, although we are badass geniuses who run a website about biology, we too would trust the chubby-yet-dependable protagonist over the lean-and-nasty heckler for bio notes because we never attended class. This, plus the obvious effort it takes to do fancy CGI animation, does make the argument for “evilution” quite compelling. Sure, the fat guy probably owns box seat tickets to the Friend-Zone, but at least he chats up bubbly Christian girls at the Teen Bible Study. Biology science journals come pre-packaged with subscriptions to beat off to freaky hentai porn alone in your basement. Do you know how embarrassing it is when those annoying subscription cards fall out at the bookstore checkout? “Hey, I’m just a biology student! I’m not a godless anarchist sodomite loner, I swear!” [1]
We do not have a fancy CGI animation team (just gedit), but we will try to be amusing. [2]
Macroevolution and Microevolution are Just Academic Departments
This movie’s core argument is that “macroevolution” is fundamentally different than “microevolution.” No, macro and micro evolution are the same phenomenon: evolution. The difference is how science about evolution is organized: macroevolution studies the mechanism of evolution over geological time scales, microevolution studies evolution over observable time scales. There are two types of evolution not because they study different natural phenomenon, but because of the pragmatic way academic departments operate. For example, theories for finding and dating fossils over millennia have little relation to the theories for studying bacteria cultures over weeks —even though both are “evolution.”
So macroevolution and microevolution aren’t two theories about the natural world, they’re just two groups of scientists who rarely consider each other’s scientific papers relevant to their work.
Yep. That’s the boring truth. Sorry.
It is reasonable to believe microevolution yet disagree with theories in macroevolution. Many scientists do. However, a world view that exclusively believes microevolution and not macroevolution would be challenged to explain why the general mechanisms of evolution must only work for human-observable time scales and no longer. One such explanation is that the Earth is 6,000 years old. This theory meets the challenge… but is the Earth only 6,000 years old? [3]
Species are Like Races: We Kinda Make Them Up
The video claims that while members of a species do evolve, new species cannot evolve from existing species.
However, The dirty little secret in biology is that we just make up what gets to be a species and what does not. And while some criteria for speciation exist like “can two members create viable offspring?”, there are exceptions. For example, wolves dogs can have viable offspring, yet we consider them different species. Breeds of dogs may have significantly different genotypes and phenotypes, yet we consider them the same species.
The way we define species is similar to how we define race: “you know it when you see it” and “if it wasn’t decided in antiquity, it doesn’t count.” If tomorrow I claim to be a new race, you can’t refute me, but you don’t believe me, either. Yet, we know it happens, because different races exist now than they did in the past. Another example is continents: which big floating rocks are defined as continents, why, and how do we reclassify as land changes?
What I’m trying to say is that if you don’t believe in speciation, you’re a racist and have sex with rocks. I hope that clears up any confusion.
Making “New Information” Is Nonsense
The video states that macroevolution “must take extra genetic information” and microevolution (adaptation) only “only works for information that’s already there… it can’t make anything new.”
A quick refutation of this common confusion is that I can have an insertion mutation (extra letters in my DNA) and pass that mutation to my children. Many other refutations exist, but that’s obviously “making new information” at the micro level.
“Conciliatory” Means “Critical of Both Sides,” Right?
Fundamentally, a child taught in today’s schools has just as much justification to believe a scientific theory as any religious theory —both are believed because somebody was paid to read it to you out of a book and call you bad if you didn’t participate. Maybe that’s not true for Stanford [4], but I had to go to lame middle-class state schools and to church every Sunday. So while I have a huge chip on my shoulder, I do empathize. People are just people, and smart people are mostly just better at rationalizing whatever they prefer to believe. It’s our fault as educated people that both videos like this and lifesaving medicine are made in the same country. I blame those bio journal basement porn subscriptions.
Footnotes
[1] Except Josh, who is. That’s actually his pickup line.
[2] We felt it would be irresponsible to file an NIH grant for CGI when clearly those funds are needed to swat sandniggerdly jihadis inconveniently living on what could be $4/gal gas that I’d have to buy.
[3] No.
[4] Though elite universities exist first to raise rich people’s children right, not necessarily to produce intellectual value, and certainly not as a reward for high school performace.
Researchers at the Stanford University School of Medicine have uncovered the first clues about the ancient origins of a mother’s intricate lifeline to her unborn baby, the placenta, which delivers oxygen and nutrients critical to the baby’s health.
The evidence suggests the placenta of humans and other mammals evolved from the much simpler tissue that attached to the inside of eggshells and enabled the embryos of our distant ancestors, the birds and reptiles, to get oxygen. … Continue Reading »
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