Interesting Topics on Evolution

1. Are humans still evolving? I mean significantly. Are we going to continue evolving bigger brains for instance. Since natural selection requires some sort of environmental pressure, typically involving either a significant culling or isolation of a population, is this likely in a world of 7 billion where people move (and procreate) freely across the planet?

2. Is group selection, as advocated most notably by the evolutionary biologist E.O. Wilson, a viable process for explaining things like altruism or can this be explained entirely by selection at the organism or gene level?

3. What is the likelihood that the emergence of life on a planet will lead to intelligent life given 100s of millions or billions of years of evolution to work with.

1. Are humans still evolving?

2. Is group selection, as advocated…

3. What is the likelihood that the emergence of life on a planet will lead to intelligent life given 100s of millions or billions of years of evolution to work with.

I don't neccessarily think one needs a bigger brain to be a smarter human.

In the context of human evolution, human vestigiality involves those characters (such as organs or behaviors) occurring in the human species that are considered vestigial—in other words having lost all or most of their original function through evolution. Although structures usually called "vestigial" often appear functionless, a vestigial structure may retain lesser functions or develop minor new ones.[1] In some cases, structures once identified as vestigal simply had an unrecognized function.[2]

The examples of human vestigiality are numerous, including the anatomical (such as the human appendix, tailbone, wisdom teeth, and inside corner of the eye), the behavioral (goose bumps and palmar grasp reflex), sensory (decreased olfaction), and molecular (junk DNA). Many human characteristics are also vestigial in other primates and related animals.

And finally, we have created such comfortable and clean environments that we have reduced much selective pressure.

eeyonkee: Healyje, (respectfully) the premise that because we are here means that the answer to 3 is high seems faulty to me. It smacks of the creationist premise that because the universe is just right for humans that it must have been designed for them.

Jan: I'm not sure I understand what you mean. However, if our current sanitary environment makes us more susceptible to superbugs emanating from other continents, and we die off in great numbers, isn't the final effect of that to reduce our role in ongoing evolution even further?

And yes you're right about "clean and comfortable" being an example of social bias. But really, have you ever tried to live in one of those societies?

it's more a question of how novel the microbe is to our exposure to it.

I think we will screw our earth up and kill ourselves off long before evolutionary pressure will demonstrate measurable results.

But the good news is that I will have lived at the very best time to be alive and will be gone before the "Crunch". Yeah!!!!!!!!!!!!

And I'm wondering if the decimation of the Native American populations wasn't an example of both - superbugs they had no previous exposure to and possibly weakened immune systems from living in sparsely populated, microbially challanged environments?

I read one of Dawson’s books (wasn‘t he the ‘THERE‘S NO GOD AND IF YOU THINK SO YOU‘RE A MORON’ guy

Ken, how is it you know Hawking and have spent time with Dawkins and Wilson. Let's hear it! :)

As for subject #3, it probably depends for how long and how fast organisms evolve. It took on Earth 500,000 years(?) to produce intelligence. Maybe intelligence is not inevitable but highly probable if given enough time?

why don't we see it

The peoples of Africa are more genetically diverse than those of the rest of the world, combined. This suggests that they may be better able to adapt to whatever environmental challenges we create for ourselves.

I don't know that we can evolve to have larger brains, or that that would be an advantage. Can human females give birth to children with larger brains, and survive?

Alternatively, if the brains grow further after birth, would an additionally prolonged adolescence be beneficial?

Nothing here is really original. We shape our views based on the work of other people.

Don't Use Metaphors

If you find yourself typing out the words, "It's kinda like if…" then stop immediately and delete what you've written... Metaphors—comparing the situation you're debating to a different situation—are the cyanide of online arguments.

If you find yourself typing out the words, "It's kinda like if…" then stop immediately and delete what you've written... Metaphors—comparing the situation you're debating to a different situation—are the cyanide of online arguments.

The Bible is the only place you can go for an explanation.

Summary: Summary

Human intelligence may be close to its evolutionary limit. Various lines of research suggest that most of the tweaks that could make us smarter would hit limits set by the laws of physics.

Brain size, for instance, helps up to a point but carries diminishing returns: brains become energy-hungry and slow. Better “wiring” across the brain also would consume energy and take up a disproportionate amount of space.

Making wires thinner would hit thermodynamic limitations similar to those that affect transistors in computer chips: communication would get noisy.

Humans, however, might still achieve higher intelligence collectively. And technology, from writing to the Internet, enables us to expand our mind outside the confines of our body.

"You must be like the wolf pack, not the six-pack."

when the Lord Jesus destroys this cursed universe and establishes a new heaven and a new earth. And in the new heaven and the new earth, there will be a different matrix.

1. Are humans still evolving?

2. Is group selection...

3. What is the likelihood...

SLR: But you have to understand that the process of genetic replication and repair is also evolving to become more accurate and sophisticated, at least in higher species.

So nerds and geeks have more children?

healyje had a not very negative experience in the military

"Evolutionary output is not only queerer than we suppose, but queerer than we can suppose."

gene-splicing idiots... the scientific fairy tale we get is that a gene gets zapped from a cosmic ray.... we get grizzly bears "experimenting" with webbed feet, instead of green feathers like a quetzal?

if you think "natural selection" is the only important thing in evolution, you need to get a bit more sophisticated than charles darwin's 19th-century thinking

This guy wrote the Origin of the Species

At this time in the science of epigenetics, the relevance of heritable epigenetic effects for the ecology and evolution of most organisms is still highly speculative.

The epigenetic effects of butyrate: potential therapeutic implications for clinical practice

Butyrate is a short chain fatty acid derived from the microbial fermentation of dietary fibers in the colon. In the last decade, multiple beneficial effects of butyrate at intestinal and extraintestinal level have been demonstrated. The mechanisms of action of butyrate are different and many of these involve an epigenetic regulation of gene expression through the inhibition of histone deacetylase. There is a growing interest in butyrate because its impact on epigenetic mechanisms will lead to more specific and efficacious therapeutic strategies for the prevention and treatment of different diseases ranging from genetic/metabolic conditions to neurological degenerative disorders. This review is focused on recent data regarding the epigenetic effects of butyrate with potential clinical implications in human medicine.

I like the idea that birds are dinosaurs

It is interesting how Lamarc’s ideas have resurfaced with the advance of epigenetics... which, of course, is some vindication for Lamarc.

"Well, a lot of far-fetched stuff has the theoretical potential to revolutionize the study of evolutionary biology, including the possibility that the DNA of any species is transcribed only when there’s a plant within 100 miles."

"This superb article by Jerry Coyne deserves the very widest attention."

"Although I’m a skeptic, and seen as a diehard supporter of neo-Darwinism, I think that an objective observer would agree that that that current paradigm is working pretty well. I haven’t yet heard the guns and shouts of revolutionaries on the horizon."

The Old Testament is responsible for more atheism, agnosticism, disbelief—call it what you will—than any book ever written; it has emptied more churches than all the counter-attractions of cinema, motor bicycle and golf course.[

"You keep using that word. I do not think it means what you think it means."

...is to find a partner who will shelter and provide so's the progeny can be successful.

Rate of molecular evolution of the seminal protein gene SEMG2 correlates with levels of female promiscuity

Postcopulatory sperm competition is a key aspect of sexual selection and is believed to drive the rapid evolution of both reproductive physiology and reproduction-related genes. It is well-established that mating behavior determines the intensity of sperm competition, with polyandry (i.e., female promiscuity) leading to fiercer sperm competition than monandry. Studies in mammals, particularly primates, showed that, owing to greater sperm competition, polyandrous taxa generally have physiological traits that make them better adapted for fertilization than monandrous species, including bigger testes, larger seminal vesicles, higher sperm counts, richer mitochondrial loading in sperm and more prominent semen coagulation. Here, we show that the degree of polyandry can also impact the dynamics of molecular evolution. Specifically, we show that the evolution of SEMG2, the gene encoding semenogelin II, a main structural component of semen coagulum, is accelerated in polyandrous primates relative to monandrous primates. Our study showcases the intimate relationship between sexual selection and the molecular evolution of reproductive genes.

TB: i think healyje's citation could bear a bit of analysis. female promiscuity would be off the chart at a hollywood party attended by an important producer, but nonexistent in certain remote mormon communities. of course, interpretation of raw data in the latter venue could easily be influenced by researcher bias.

A developmental dynamics perspective allows researchers to abandon popular yet misleading metaphorical references to gene
action (e.g., genes as the storehouse of information or programs for development, genes as the overseers or regulators of development) in favor of characterizing gene activity as a molecular, intracellular event (Johnston & Edwards, 2002). Such an approach emphasizes the unpacking of the mechanics of developmental processes and would include (as first steps) coordinated interdisciplinary efforts to (a) systematically identify individual DNA sequences and their associated products, (b) determine the nongenetic factors involved in constructing and regulating the structure and function of the these products, (c) trace these products and their influence across the various levels of organization that make up the individual organism, and (d) determine how previous developmental outcomes and current experiences influence these processes in ecologically meaningful contexts (see Wagner, Chiu, & Laubichler, 2000, for a similar evo-devo view). The psychological sciences have much to offer in this effort, particularly to explain how previous developmental outcomes and current experiences influence these biological processes in specific contexts.

Viewing genes as reciprocal partners in the developmental processes underlying phenotypic traits and characters requires a shift
in the way the “environment” is typically characterized in discussions of both development and evolution. From a developmental
dynamics framework, the environment cannot be reduced to “supportive conditions” or to an abstract “poser of problems” that must be solved—both common perspectives within contemporary evolutionary psychology. Rather, the specific physical, biological, and social environments within which the individual organism develops are recognized to be inseparable parts of the developmental system. Hence, the organism and its environment are best characterized as codefining (Turvey & Shaw, 1995), and evolution can be seen to result from a dialectical interaction between organisms and environments through ontogeny (Levins & Lewontin, 1985). Attempts to rigidly dichotomize the contributions of the organism and its environment to development or evolution typically lead to the need to invoke other troubling and unnecessary dichotomies, including the nondevelopmental phylogenetic–ontogenetic causal framework reviewed in previous sections and widely embraced by evolutionary psychologists. Whereas such dichotomies have allowed evolutionary psychologists to virtually ignore developmental dynamics in their accounts of human development and behavior (by arguing that they are interested in phylogenetic rather than ontogenetic questions), we argue that evolutionary and developmental frameworks do not provide fundamentally different ways of explaining behavior. Rather, developmental processes are fundamental both to individual development and to evolutionary change.

Instead of asking reductionistic questions about the genetic basis of human development and behavior, a developmental dynamics
approach is interested in what are the contributions of the various components and levels of the organism–environment system and their interactions to phenotypic outcome. This empirically based unpacking of the mechanics of developmental processes requires going beyond the notion of the causal powers of the gene and focusing on the broader relational principles that govern and constrain development and evolution.

the evolutionary psychologists have come up with a great explanation for the battle of the sexes. men and women have differing interests, due to the very nature of gender, for forwarding their personal genes into spacetime. because men can potentially have an almost unlimited number of offspring, they tend to be promiscuous. women, on the other hand, produce one sex cell per month. if they become impregnated, it'll take nine months to produce a child, followed by weaning. most women don't want to bang 'em out once a year, in spite of the papal imperative. so more is not better for a woman. they tend to be choosy. their best strategy for long-term gene forwarding is to find a quality partner who will shelter and provide so's the progeny can be successful.

due to the very nature of gender, for forwarding their personal genes into spacetime.

their best strategy for long-term gene forwarding is to find a quality partner who will shelter and provide so's the progeny can be successful.

Like Mayr, most evolutionary psychologists argue for the heuristic value of the conceptual decoupling of proximate (ontogenetic)
and evolutionary (phylogenetic) levels of explanation (see Buss, 1999; Crawford, 1998; Daly & Wilson, 1978; Gaulin &
McBurney, 2002). Furthermore, most assume that evolutionary factors are somehow ontologically prior to and more fundamental
than proximate factors in directing phenotypic outcomes. This viewpoint is evident in nearly all current evolutionary accounts of
human behavior and development (but see Bjorklund & Pellegrini, 2002, for a well-developed exception). Lickliter and Berry (1990) termed this dichotomous conceptual framework the phylogeny fallacy. The phylogeny fallacy is based on the assumptions (a) that phylogeny and ontogeny are alternative processes by which information is made available to the developing individual and (b) that specification for an organism’s phenotype can exist independently and in advance of its real-time developmental processes (see also Ingold, 2001; Oyama, 1985). This framework is based (often implicitly) on a strong form of genetic predeterminism and ignores or downplays the fundamental role of developmental processes in the realization of all phenotypic characters or traits.

Assertions of polyandry have nothing to do with sociology or psychology, but rather everything to the evolution of the human male and [particularly] female reproduction system relative to sperm competition.

Jan: Or perhaps biology uses the terms differently than anthropologists do?

there is considerable evidence of efficacy for several mind-body therapies in the treatment of coronary artery disease (eg, cardiac rehabilitation), headaches, insomnia, incontinence, chronic low back pain, disease and treatment-related symptoms of cancer, and improving postsurgical outcomes.

We propose that clinical symptoms may be modified by mind-body therapies through several interrelated mechanisms, including: (a) activation of specific EHN structures, resulting in functional cortical (and subcortical) reorganization and improved interhemispheric balance; (b) more efficient cortical modulation of limbic and brainstem homeostatic centers and enhanced peripheral-central integration of information, expressed at the periphery as a change in autonomic (sympathovagal) balance and immune (pro-inflammatory cytokine profile) function; (c) re-patterning of primary interoceptive and higher-order homeostatic representations, resulting in more adaptive long-term psychophysiological responses as well as reduced expression of adverse symptoms; and (d) modulation of the epigenetic regulators (e.g., growth factors, hormones, histone function, DNA methylation) that can mediate cellular responses to environmental stress. In this way, mind-body therapies ameliorate symptoms via influence at multiple levels, from gene expression (cellular level) to the interaction of cortical brain regions that mediate systemic responses to internal and external challenges, including stress.

Currently, behavioral development is thought to result from the interplay among genetic inheritance, congenital
characteristics, cultural contexts, and parental practices as they directly impact the individual. Evolutionary ecology points to another contributor, epigenetic inheritance, the transmission to offspring of parental phenotypic responses to environmental challenges—even when the young do not experience the challenges themselves. Genetic inheritance is not altered, gene expression is. Organismic pathways for such transmission
exist. Maternal stress during the latter half of a daughter’s gestation may affect not only the daughter’s but also grand-offspring’s physical growth. The author argues that temperamental variation may be influenced in the same way. Implications for theory and research design are presented along with testable predictions.

I'm finding those epigenetic papers a little technical and hard to wrap my head around. If that was my introduction to this subject, I don't think that I would have the passion for it that I do.

Part of evolutionary strategy: if you're past reproductive age, you don't warrant upkeep.

Altruism is considered a hallmark of the human species’ success, and it’s a well-documented developmental milestone. Kids start off highly selfish and remain that way through preschool, but at about age six they start to become a bit more generous. This pattern, however, has only been studied in relatively affluent kids living in relatively peaceful circumstances. It’s entirely unknown if children would continue to act altruistically in the face of adversity. Will the precocious altruism of childhood survive severe tribulation, or will kids revert back to their earlier self-centeredness? The Sichuan earthquake provided a natural “stress test” to examine the strength of youthful generosity.

Before the earthquake hit, the scientists had given 6- and 9-year-old a version of what’s called the Dictator Game—considered the gold standard for measuring altruism in the lab. Working individually with a researcher, each child is allowed to select stickers to keep. But then afterward, they are asked if they would like to give some of their own stickers to an anonymous classmate who is not playing the game—and therefore has no stickers. The children make their donations in a sealed envelope, so they believe that nobody knows how much, if anything, they are giving away.

But the scientists do know, and this group of kids fit the normal pattern. That is, 6- and 9-year-olds were not significantly different in their altruistic giving in the time before the earthquake. Then, one month after the earthquake, the scientists gave the same test to another, similar group of 6- and 9-year-olds. (They couldn’t follow up with the same children, because they could not locate many of them.) They wanted to see if the normal development of altruism was affected by the disaster experience, in either age group.

And it was, in an interesting way. The 9-year-olds actually gave much more—they were more generous—after the earthquake than before. The experience appeared to solidify and indeed enhance their altruism. But the younger kids gave significantly less than before the quake. The immediate effect of the disaster was to make the 6-year-olds more selfish. Put another way, their new-found altruism did not survive the earthquake.
...
Three years after the earthquake, the kids’ altruistic giving returned to pre-quake levels, suggesting that the earlier changes were an acute response to the immediate aftermath of the disaster. In other words, the younger children opted for self-preservation in a crisis, suggesting that their emerging generosity is still fragile—but this reaction was not long-lasting. The altruism of the older children was apparently robust enough to withstand the challenge of adversity. Importantly, empathy for other victims was the pathway to generous action.

So then I got to thinking, I wonder how many children Ghengis Khan had after the age of, say, 55?

Demographic theory suggests that polygyny may occur because of a surplus of women that results from a high incidence of male warfare. However, polygyny occurs in many situations of relatively balanced gender ratios or even, as in the case of the Yanomamo, where males outnumber females. Accordingly, some men accumulate two or more wives only at the expense of others who never marry, or, much more usually, marry at a later age than women do. As such, the society becomes divided between young bachelors, who may remain single into their thirties and older polygynists. This arrangement may occur informally or may become a marked feature of the social structure. For example, in some South African societies, such as the Zulu, all young men in their twenties were organized into military “age regiments” and were not allowed to marry until their term of service ended. As we have already suggested, differences in marital age are also created by bride wealth requirements.

The social division between polygynists and bachelors points to another prevalent theory of polygyny, which is based on social stratification. In societies where men are not distinguished by differences in access to productive resources, such as land and capital, status distinctions are mainly attained and expressed through direct control over people. This goal is most obviously acheived through incorporating many women into one’s domestic group and expanding it by fathering a large number of children. A stratificational theory of polygyny also accounts for its greater incidence in comparison to polyandry, since men tend to occupy higher statuses than women in the majority of societies.

What ethical hangups ?

Bringing back one Neanderthal? What are you going to do, make a pet out of the poor thing?