Homosexuality in animals and humans

Interesting ops piece I just ran across while studying about homosexuality and animals and humans...
http://www.themalaysianinsider.com/opinion/article/it-is-homophobia-that-is-unnatural

-RYAN GUPTA

Being insecure: how bad is it?

Today there is plenty of information on “unhealthy” relationships and how to build secure and stable attachments to people.  However, despite it being so good, a large portion of the human population do not form “healthy” relationships.  How does this fit into an evolutionary perspective?

A paper came out by Ein-Dor et al. trying to address a proposed paradox, that individuals who form secure attachments have an evolutionary advantage but almost half of the human species can be classified as insecure in attachments.  This group proposed that while insecure individuals have a lower fitness, mixed groups of individuals are better adapted for survival than groups of only secure individuals.  Their hypothesis depends on the assumption that these traits evolved in closely related groups, and that forming insecure attachments is always detrimental to the individual.  Frankenhuis published a response arguing against this hypothesis, or at least in favor of further testing.  According to him, the tendency to form insecure attachments could have developed as an individually advantageous trait in environments where help is less often offered.  He argues that there are several holes in Ein-Dor et al.’s hypothesis.  For one, they tested homogeneously secure groups and heterogeneous groups, not homogeneously insecure groups.  They also did not consider the effect of the kinds of environments where insecure attachment patterns are more prevalent or provide evidence that social groups were comprised of individuals closely related enough to support a group benefit hypothesis.  In more simple terms the debate is whether “unhealthy” relationships can be traced back to a time and place in human history where people who tried to create “healthy” relationships were hurt and trust was a disadvantage.


The original paper:
http://pps.sagepub.com/content/5/2/123.short
Commentary by Frankenhuis:
http://www.frontiersin.org/Evolutionary_Psychology/10.3389/fpsyg.2010.00172/full


- Nicole Scott

Morality: Where did it come from?

            A debate is raging between philosophers and biologists. As we learn more about the evolution of morality, some evolutionists are staking claim to the topic of morality as a biological one, not a philosophical one.

            The idea that morality is derived from our primate predecessors dates back to the 70s and it hinges on the idea that our human morality stems directly from the primates’ sociality tenants: empathy, the ability to learn and follow social rules, reciprocity and peacemaking.

            These fundamental virtues drove the actions in primate communities that from a humanistic perspective seem quite “moral.” For example, chimps share food more often with other chimps that have groomed them. Chimps will also make up and console the loser after fights. Often, female chimps will even prevent a fight from happening.

All of these moralistic sorts of actions ultimately stem from an innate fitness advantage. Maintaining a happy and unified community is important in working together for survival. Thus these exhibitions of morality by primates may be driven by a necessity for survival, yet they are nonetheless, the precursors to what humans call morality.

Human morality seems to be driven by more of an innate sense of righteousness than any sort of urgent necessity for survival, but the parallels between primate and human morality are evident.

Perhaps philosophers and biologists need not work separately on the topic of morality but instead simply acknowledge that one field is able to describe the origins and history of morality while the other field is equipped to focus on the uniquely human aspects of morality.

            Check out this article on the evolution of morality: http://www.nytimes.com/2007/03/21/health/21iht-snmorals.4978821.html?_r=1

-RYAN GUPTA

The ant equivalent of our cattle industry

There is a very interesting phenomenon afoot in the tiny world of ants. It seems that much as human culture has developed a strong agricultural system, so have certain species of ants. In a manner similar to humans’ herding and maintenance of herds of cattle, ants also keep and farm groups of aphids.

The behavior is beneficial for both species. The ants are able to keep a sustainable and constantly available food source with the sugary and edible secretions of aphids, while the aphids, as a community on the whole, receive protection from outside prey.

Developments have been made in understanding how ants maintain these colonies specifically. According to research from the Royal Holloway University of London, the ants disperse small quantities of tranquilizer in each step. Thus areas where the ants walk the most as a population have the highest concentration of tranquilizer. This tranquilizer affects the aphids and slows their movement. In fact, the researchers found that aphid movement was measured to be slower on paper that ants had previously walked on, when compared to control paper that ants had not previously walked on. Using this tranquilizer methodology, the ants can rely on each other to keep the boundaries of aphid movement quite limited.

The researchers speculate that by releasing tranquilizers from their feet, ant populations are better able to control the movement of aphids and make sure that they don’t stray too far; in doing this ants are ensuring the continuity of their honeydew food source. From the aphids’ perspective, its not a bad deal either, because as long as they stay in the proximity of the ants, they are less susceptible to predation, as ants will fend away another potential predators such as ladybugs.

Check out the article here: http://www.sciencedaily.com/releases/2007/10/071009212548.htm




-RYAN GUPTA

Storytelling for survival

Were kids who listened to their bedtime stories better at being adults?  According to a paper by Michelle Scalise Sugiyama, storytelling may have developed as another aspect of parental care and the preparation of offspring for the challenges of a forager.  Language conferred evolutionary advantages to our foraging ancestors, as more information could be shared that was dangerous to find out first-hand.  In addition to helping out kin, sharing information with those who could reciprocate in the future helped minimize risks associated with finding resources, etc.  These are all benefits of sharing among active adults who were involved in foraging.  However, there is also a strong old to young oral tradition, whether by children overhearing stories of the hunt or direct storytelling, that could have conferred additional advantages.  In addition to resources, an important part of parental care was the passing down of knowledge.  Warnings and advice would have been one aspect.  The narrative would have been another important way of transmitting knowledge and increasing offspring survival.  Specifically, the main hypothesis explored was that the vicarious experience of stories prepared offspring to plan, a cognitive process important to foraging lifestyles, through increasing episodic memory.  The paper combines anthropology, cognitive studies in development, and evolution for evidence.
http://www.frontiersin.org/Evolutionary_Psychology/10.3389/fpsyg.2011.00133/abstract


-Nicole Scott

Is Kin Selection Wrong?

In a stunning example of the inevitable marching forward of science, prominent ecologist E.O. Wilson, famed for helping lay the groundwork for modern theories which explain the genesis of social evolution, is now rejecting his own work. Originally, the favored explanation for altruistic behavior - one of the foundations of sociality - was kin selection. Kin selection is an evolutionary theory which asserts organisms can increase their fitness through actions which harm them individually. As long as their actions benefit other organisms which share, or are likely to share their genes, the altruist increases its inclusive fitness.

This was widely supported in the ecological community, because many of its predictions were born out. Organisms which resided in community nests developed sociality faster than organisms which lacked them. Organisms with strong family-rearing instincts formed into colonies of social organisms more frequently than lone wolf species.

However, according to Wilson, all that is circumstantial. In his new paper, Wilson cites group selection as the driving force behind altruism and, by extension, sociality. Group selection differs from kin selection mostly in the level of selection. Kin selection takes place at the genetic level, because inclusive fitness can increase and decrease regardless of which individual organism carries the genes. Even if an allele codes for a suicidally altruistic behavior, if that behavior causes enough relatives to survive and thereby increase the frequency of the gene in the next generation, it is still a beneficial trait. In contrast, group selection takes place at the level of organism group. Competition between groups of organisms puts a separate set of selective pressures on the individuals in the groups, promoting behaviors like selflessness and altruism, because groups made of those types of individuals out-compete groups of selfish jerks. Wilson asserts that in this scenario, high relatedness within groups is a symptom of close proximity for some time, no a cause of group formation in the first place.

Wilson’s new theories are extremely controversial within the scientific community - many ecologists consider him to have lost credibility for suggesting that kin selection is false. As for myself, I don’t think that Dr. Wilson should lose credibility, but I am not sure if I believe his assertions. His theory of group selection does not adequately explain why groups of cooperating organisms formed in the first place. Furthermore, kin selection makes several predictions which group selection does not, which nature has proven to be true. For example, kin selection implies that organisms with higher relatedness should be more social. Lo and behold, order hymenoptera, a haplodiploid gender determinant group, has a higher proportion of eusocial organisms than any other order. Given that one quirk of haplodiploid sex determination is a higher relatedness to one’s siblings than to one’s own children, it is easy to see how this supports kin selection.

You can read E.O. Wilson’s entire paper at http://www.biology.ed.ac.uk/archive/conferences/evolbiol2006/papers/Wilson.pdf and come to your own conclusion about this large debate.

-Adam Geiger

So That’s Why They Call it Humanity

Biologists have long been fascinated with the interactions between animals, both inter- and intra-species relations, studying everything from parasitisms to mutalisms, sexual selection to family groups to true eusociality. Yet the one constant that remains through the vast amounts of diversity when you get to the root of all actions is selfishness. Every action that every organism willingly performs benefits the actor in some way, otherwise it would be selected out. Every organism, that is, except for humans. We humans have found a way to defy natural selection (wouldn’t Darwin be disgusted?) through acts of compassion.

There is evidence that as early as six million years ago, human ancestors began displaying the first hints of empathy. An article published in Nature titled A Possible Case of Hypervitaminosis A in "Homo erectus" implies that even Homo erectus displayed feelings of compassion by feeding, protecting and caring for a woman who developed a paralyzingly painful condition. DiscoveryNews published an article a year-and-a-half ago that outlines the proposed evolutionary model for the development of human compassion. This is hugely exciting! As far as I can tell, Homo sapiens is the only extant species that forms such strong bonds of friendship and even cares about the general well-being of total strangers. Chimpanzees, our closest living relative, certainly do not exhibit the same kindness. Jane Goodall recounts in her reports the fate of an older male chimp named McGregor who suffered from polio. The paralyzed chimp was shunned, attacked on multiple occasions, and excluded from social activities despite efforts to join.

Perhaps some would consider compassion a frail trait, seeing as how it is only present in one species. They may even say it is maladaptive – after all, it tends to lower fitness. But I say we humans thrive on compassion. It may not be personally beneficial, but it benefits the species as a whole. No other species is capable of such a global perspective. So next time you hear someone talk about ‘losing their faith in humanity’, just remember that compassion has been around for millions of years. I don’t think it’s going anywhere any time soon.

-Elizabeth Richardson

Getting Sick Of It: How Caterpillars Try To Cheat the Group Protection System (and Fail)

Group protection is probably one of the most basic goals of social interaction between organisms. As the old adage goes, "there's always safety in numbers". But what if this social theory is wrong? How do you explain that? 

A recent study looked at a species of caterpillar called Pieris brassicae which when attacked by a predator will regurgitate its last meal, producing a foul smelling compound that often causes the predator to avoid the caterpillar. However, by doing this, the caterpillar loses out on valuable nutrients from the meal and often experiences stunted growth as a result. As a result, the caterpillar only employs this defensive mechanism when it is absolutely necessary because the individual cost to doing so is very high.

For a previously unknown reason, it has been shown that forming groups of these caterpillars for the purpose of protection does not result in a greater chance of survival on an individual basis. To explain this, the study looked at the individual behavior of the caterpillars alone and in groups. What they found was that when in a group, the caterpillar's rate and volume of regurgitation decreased significantly as opposed to in an isolated environment. This shows that the caterpillar is able to modulate its response based on if there are other individuals who are capable of performing the same act. This also shows that each individual reduces their contribution towards group protection, which in this case is enough to cancel out the supposed benefit that group formation gives for fitness. 

The full article can be read at http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2012.01770.x/full

-Eric Baeuerle

Other species have best friends too!

Turns out humans aren't the only species that benefit from making friends with non-kin!  As humans, we benefit from having close friends in that they help us manage stress which can help lead to a longer life.  Turns out that, in other species, having a close friend can actually be an evolutionary advantage: organisms with close friends are more likely to reproduce and are better at fighting diseases.  Some male chimpanzees spend significantly more time with certain other chimpanzees; they groom each other, share meat, and even hunt together.  Some female baboons groom certain other baboons much more than others and are more likely to help out a baboon that has recently groomed them.  If a fight ensues shortly after the grooming, having that extra baboon friend to help out could almost certainly mean the difference between life and death.  These baboons that form close bonds have more surviving offspring and live longer.  These results have also been found in other monkeys, lions, elephants, dolphins, and rodents.  It was recently discovered that female horses in New Zealand tend to form friendships with non-relatives in order to keep aggressive stallions at bay.  Mares risk their lives to help their friends with the expectation that the same help will be given if they ever need help with aggressive stallions.  Researchers are currently trying to understand how this occurs physiologically.  Thus far, they have pinpointed both a particular social-bonding hormone and oxytocin in monkeys; monkeys with more of these hormones are more generous.  Hopefully, further research in this area will help us to understand how human's tendency to form such close bonds with unrelated individuals evolved.

Here's the link to the article, check it out!

http://www.sciencenews.org/view/feature/id/339326/title/Furry_Friends_Forever

-Cristina Terhoeve

Eusociality of termites

An article was very recently published called "Brood care and social evolution in termites." The full text of this article is still not yet available at Rice, but the study presents some intriguing findings. The evolutionary community has always assumed that cooperative brood care was a necessary component for eusociality and a driving force of social evolution. However, this study looked at four different species of termites and found that cooperative brood care was common in only one of them. It appears that the evolution of eusociality in termites may have actually been driven by increased defense!

The abstract of the article can be found at http://rspb.royalsocietypublishing.org/content/early/2012/03/01/rspb.2011.2639.abstract

-Elizabeth Richardson

Is there an evolutionary basis to being nice to old people?

Humans, by nature, are an altruistic species. Unless we're affected by a mental illness, most of us feel bad about doing bad things and good about doing good things. We live by morals and we help our own, and this is especially true regarding our treatment of our elderly. We do our best to make sure Grandma and Grandpa are comfortable and taken care of, if not in our own homes, than with trusted medical staff. We don't always succeed in getting them the best treatment, but we try our hardest, with the best intentions. The topic on my mind today is, is this exclusively a human behavior, or is it a 'thing' across the animal kingdom? And if so, why? We have seen in class that animals have developed altruistic behavior in order to help relatives reproduce, but that is a different scenario. I'm not saying we should neglect old people; that would be terrible, but what, if it exists, is the advantage of altruism toward members of the species that are no longer reproductive?

After Googling around, I stumbled upon the expert opinion of evolutionary biologist Dana Krempels, who confirms that this behavior is indeed rare. Humans live in relative luxury and have no natural predators, so we can afford to practice behaviors that would be maladaptive in a hostile environment where the danger of predators lurks around every corner. Interestingly, though, in some cases altruism towards the elderly does develop in animals that have a sophisticated social order. Read more about it here.

-Mindy MacKay