Evolution!

The evolution and biological iteration of the primate is one of the most fascinating aspects of the historical "timeline of life". For a non-biologist/anthropologist, primate evolution may appear quite complicated and interconnected. In this blog, I will break down this complex process into some simple milestones and explain how we arrived at the species of monkeys that currently roam our world.

 

The very first class of creatures to resemble a primate was the Euarchonta, an early class of mammal that appeared around 70 million years ago (mya). This half-squirrel, half-primate was tree-living with claws and forward facing eyes (located on both sides of its head). The next milestone for primate evolution occurred around 40 million years ago, during which the early proto-primates split up into two groups with distinct and emerging characteristics, the Strepsirrhini (wet-nosed) and Haplorrhini (dry-nosed) primates. The Strepsirrhini developed into lemurs and lorises, some of the smaller-bodied, rodent-like, truly tree-dwelling primates. However, the Haplorrhini as a group diverged again about 10 million years later into what we now call "New World monkeys" and "Old World monkeys".

New World and Old World monkeys spent the next 20 million or so years further evolving and defining themselves (through a process called speciation), but their key and differentiating characteristics remain the same today. New World monkeys feature a flat nose, longer prehensile tails (a functional tail used for tree-swinging), small to mid-sized bodies, and live in the tropical canopy of Central and South America. Some of these primates include the spider monkey, sakis, marmosets, and tamarins. In contrast, Old World monkeys are probably the ones you pay close attention to at your local zoo. These primates feature a downward-facing nose, mid to large-sized bodies, non-prehensile tails, anywhere from partial tree-dweller to land-dweller, and live in a range of habitats across Africa and Asia. Some of these primates include baboons, gorillas, and macaques. These primates survived quite well and developed into the human era around 7 million years ago.

"iloveprimates.com" Blog Review

Response to the blog: http://iloveprimates.com/2011/12/reciprocal-altruism/

Researchers continue to try to understand Reciprocal altruism/reciprocal altruism in nature. Altruism in nature is typically defined as an unselfish act that benefits another (non-kin). This concept, as it manifests itself nature seems very strange, based on the foundations of Darwinian evolution—that any trait to share or benefit another (non-kin) at one's expense is not likely to survive multiple generations. However, reciprocal altruism can be more complicated because some benefit may come back to the initiating participant, with ultimate advantages for both participants. In this blog, I will respond to a blog post that explores the question of reciprocal altruism in primates (see link above).

Snub-Nosed Monkey (Photos)

The blog post does a nice job of introducing the concept of reciprocal altruism. Indeed, the Trivers work, The Evolution of Reciprocal Altruism, suggests that the participants must have the ability to remember one another (primates have exceptional longer-term memory) and the cost of giving (time spent grooming, food shared, etc) must be outweighed by the reciprocated benefit (coalition support, food sharing, etc). The blog post provides two specific examples from vervet monkeys and male chimpanzees, and includes a short video of this type of behavior (The Video).

Interestingly, reciprocal altruism has been explored across many species including various insects, bees, birds, etc. Despite the high-level overview from iloveprimates.com, there are some additional research perspectives and context that help to frame the discussion. One such insight is that the reciprocal altruism tends to occur between "high-ranking" individuals. This is important because it means that this relationship dynamic is even less "altruistic" if primates lower down the pecking order do not have access to such opportunities. Additionally, evidence has shown that the level of reciprocity is quite equal (think banana for banana), but there can be variation for reciprocating up the ladder to a "high ranking" individual. Finally, data analysis has revealed the complexity and range of these altruistic acts, from grooming, food-sharing, and fighting coalitions. This evidence is important because it means that higher forms of altruism existed prior to the development human-like cognitive abilities. So, keep how far humans have evolved in context the next time you lend someone your metrocard or donate money to a cause!

Evolution, Primatology, and Politics

An interesting topic in the news lately has been the issue of teaching evolution across public, primary and secondary schools. As the Republican Presidential Nomination process continues, the more conservative candidates and the conservative media have once more engaged with this topic. Catering to their conservative beliefs and constituents, Presidential candidates such as Mitt Romney and Rick Santorum have used interesting language to characterize biological evolution. These well educated, career politicians claim that evolution is a "theory with holes" and that education must balance evolution with God, Creationism, and Intelligent Design. Mitt Romney, the leading Republican candidate, has recently stated, "I believe that God designed the universe and created the universe. I'm not exactly sure what is meant by intelligence design." Other candidates, such as Rick Santorum, have previously authored an Amendment to teach intelligent design attached to No Child Left Behind. 

God, shown here in the center organized evolution according to intelligent design

Regardless of political affiliation and beliefs, we must all think about the impact and consequences of teaching any other evolution perspectives beside biological evolution. Do we have strong evidence to support intelligent design? Do we have a body of evidence to refute biological evolution? Is it proper for a government-sponsored education system to inject faith and religious beliefs into science? How can the existence of primates and their extreme similarities to humans be consumed by other theories? The debate will continue and unfold into the Fall, but educators and voters must decide a path forward that is sure to shape how we see ourselves and primates in the future.