No, humans did not evolve from monkeys

Frequently used image depicting evolution

I often hear, "humans evolved from monkeys" or substitute monkeys for apes or chimps. Unfortunately, this is a common misconception. It's simply inaccurate and a result of poor understanding of how evolution works. Humans did not in any circumstances evolve from monkeys or chimps or lemurs. For the sake of clarity, let me repeat, humans did not evolve from monkeys or chimps or lemurs. I'm not about to go on a creationist rant but I am about to explain hopefully dispel some common misconceptions about evolution. To understand why saying humans evolved from monkeys is so wrong, we first need to take a closer look at how evolution work and we're going to start with phylogenetic trees. A phylogenetic tree is a visual representation of the evolutionary relationships between species. They're often just called trees for short and they're very useful. If we look at the one below, we see multiple species (named "A" and "B" and so forth). The nodes or areas where multiple lines come together represent common ancestors.

For example, if we trace species A back through time we see it eventually connects at a spot I've labeled X. The same is true for species B and C: we can trace their lines back to species X.

Example of a phylogenetic tree

 Species A, B, and C are all descendants of species X, which no longer exists. Species X is the last common ancestor species A, B, and C shared. A common ancestor is simply an ancestor that two or more species have in common, and the last common ancestor is the most recent common ancestor of two or more species. If we keep traveling down the line of A (and back in time), we see that species Z is also a common ancestor of A and B, but the last common ancestor of A and B is species X. There's a slight difference in meaning between common ancestor and last common ancestor. All of the species on this tree originally evolved from species Z, but this was a very long time ago. Usually, trees represent millions of years. Over time, species change. Species Z was one species at the start of this tree, but something happened (either gradually or suddenly) to make this species split into two different species, X and Y. Maybe one population was separated by another due to an earthquake, as time progressed, those two populations became so different from each other, they formed new species (X and Y).  Species X may have been separated from a critical food source, and thus gradually began foraging only at dusk and dawn for insects, whereas the other population started interbreeding with another population made up of only white-colored individuals. Over time, the two become distinct populations and eventually distinct species.

Close-up of some of the phylogenetic tree

Let's take a closer look at another side of the tree and pretend that these alphabetically named species are species of monkeys. D, E, and F separated or diverged from species Y. If I look the tree over from the top to the bottom, I see that species D, E, and F are relatively young (their lines separating them from Y are relatively short), and that species Y spent a great deal of time successfully as species Y before it split into multiple species. Let's say one of the main reasons why species Y split into multiple species was because a new predator was introduced into the habitat. One population of Y changes its behavior and activity patterns to become nocturnal, thus avoiding the diurnal predator entirely. That population becomes E. Enough time passes and E can no longer breed with close relatives, D or F. Another population E finds success in foraging lower in the canopy, thus avoiding the predator, which let's say is some sort of predatory bird. E forages lower in the canopy but has to make behavioral changes to do so, feeding on different items and relying on its tail less to balance on thicker tree branches. Over time, E becomes a distinct species and cannot breed with F or D. It retains some success for a while but eventually it begins to lose numbers due to feeding competition from other animals occupying this part of the canopy, and E goes extinct. This is why species E's line does not extend all the way to the top of the tree, or the present time. It did not survive. The same is true for species D, which managed to adopt certain vigilance behaviors to avoid the predator, but was sadly wiped out from a disease that destroyed the population.

If you follow the lines, you can see that species F eventually splits again into separate species, making species F an ancestral species. It is the last common ancestor to H and I, both of which still survive to this day. Species H is more closely related to species I than it is to species C, which it last shared a common ancestor with a long time ago. That means that H and I will share more characteristics than species I and C.

Tree showing relationship of great apes and humans

Now, all you have to do is apply this to primates. Chimpanzees, lemurs, and so forth are all living species. Replace A with lemurs and I with humans and you can see immediately that we did not evolve from lemurs. A does not come from I. That's obviously wrong. However, A and I do share a common ancestor, Z. Now, these A and I have been evolving, over time, separately for a while. They've taken different paths, but they do share a common ancestor, a common ancestor, Z, which is no longer alive. It may seem like a small difference, but the number of people who actually believe that we did evolve from monkeys is perhaps greater than we'd all like to believe. By saying, we shared a common ancestor with monkeys or we evolved from an ape-like ancestor as did chimpanzees, some of the confusion might be avoided. Or someone may ask you to clarify, and you can explain that humans did not, in fact, evolve from chimpanzees. Looking back to the first image depicting evolution of humans, if you said that first animal was a gorilla, that would be inaccurate. If you said it was an ancestor of both gorillas and humans, you'd be okay.

It's important to remember that while it looks like species H and I separated from each other at a very distinct point according to this tree, that's not always the case. Populations are always evolving, and it may take a few generations or a hundred generations for a species to gradually become a separate one. It is humans who define when exactly a species arises or diverges, but the reality is that it is a process, and the exact time when one species became two is debatable. There usually isn't a right answer. Scientists are forever learning about species, finding new ones, and reassembling these trees using the best information available. The end of the tree, in our case A, B, and so forth, don't need to represent species. You could do a phylogenetic tree and go as far as genera if you'd like or go all the way to subspecies even. It depends on what your purpose is.

True or false: humans are more closely related to orangutans than gorillas.
Answer: false
True or false: humans are more closely related to chimpanzees than bonobos.
Answer: false. If you switch bonobos and chimpanzees in the tree above, you'd be within your right to do so. The same amount of time has passed since we split from the last common ancestor we shared with both species.


Further reading:
Reading trees: a quick review
Chimpanzees and humans may have split much earlier than thought
Phylogenetic tree of primates
Large phylogenetic tree based on genetics

Research experience as an undergraduate student (or earlier)

Courtesy: National Science Foundation

Whether you're an undergraduate biology major or a high-school student figuring out whether or not you want to be a biology major, getting research experience is a wise idea. In fact, it's arguably even essential, depending on what stage of your education/career you're in.

More people are getting their undergraduate degree than ever before. Many students do well in terms of grades and have excellent recommendation letters from their professors. By gaining research experience, you set yourself apart from the majority in a competitive field. You show that you can use all of the knowledge from the books and apply it, and moving beyond the book smarts is important. I think it's in most (if not all) students best interest to gain research experience before graduating.

There are multiple ways to do this: choose coursework that includes independent research as part of the course, do an independent study with a professor in your department or a department you're interested in, do an undergraduate thesis if you're really willing to take on the work load, or gain your research experience over the summer.

Many universities have research experience for undergraduates (REU) programs that take place over the summer. These are programs specifically designed with undergrads in mind. They typically don't require any previous research experience, although some may require certain coursework or that you be in you junior or senior year of your degree. You'll work with a faculty member and you'll be paid to do research. Housing is also usually provided.

Courtesy: National Science Foundation

The experience you have in an REU will depend on the project itself and the faculty member running the project. You may find yourself working under the guidance of a graduate student on a daily basis or you may find that you do your assigned work and check in with the faculty member every few days or so. Most REUs accept only ten or so students and they can be quite competitive. Check out this PDF from the University of Wisconsin-Madison on what an REU is, applying for one, and why you should do one.

If an REU isn't for you, there are still plenty of other options. Doing an independent study for a semester or two allows you to work one-on-one with a professor and assist with his/her research. You can develop a deep understanding of a specific topic, learn about what the research process is like, and earn a grade and credits for your efforts. If you play your cards right and enjoy the experience, that professor you work with can also be a great reference, as he/she will really get to know you over the time.

There are many parts of the research process: the initial design, applying for funding, preliminary data collection, experiment design, redesign, data analysis, and writing up your results. Try and get experience in as many of these areas as possible or talk to your professors or supervisors about their experiences. This is a time in your life when you can gain experience and learn a lot from your supervisors and other project mentors. It may seem a bit intimidating, but everyone knows you're an undergraduate, a newbie. The point is to contribute and learn. 

Whether you choose to do an REU, an independent study, a larger undergraduate thesis, or purposefully enroll in courses with research as a component, there is nothing like gaining hands-on experience. You'll discover whether or not you like working in a lab or want to work in the field. You'll find out if you're great at designing your own projects or if you're better at following directions. A career as a research scientist is not for everyone just as fieldwork is not for everyone or lab work. The only way you will find any of this out is by exploring it yourself. Having these experiences will set you apart and make you more unique as an applicant for jobs or graduate programs. I don't think it's a stretch to say that you need to have some sort of research experience to be a competitive applicant for graduate programs, as more and more people are pursing post-graduate degrees. Potential graduate advisors want to know that you can do the research you're applying to work with them for. They don't want to send you out to the field and find out you can't stand the bugs and want to come home! Regardless of whether you want to apply to grad school, you should gain some research experience because you'll leave university with a better understanding of the work you are best at and the work you enjoy.

This is around the time when some REU applications are due. I've listed some REUs below, some of which are funded through the National Science Foundation (NSF).

NSF-funded project with the Enchinacea Project with opportunities for undergraduates, recent graduates, or even graduate students.
Experience for high-school student, undergraduates, and even teachers with Rocky Mountain Biological Laboratory.
REU with Models in Evolution, Ecology, and Systematics through Kent State.
Aquatic Chemical Ecology REU through Georgia Tech sponsored by NSF.
NSF-sponsored ten week program for undergraduates to do independent and collaborative research in the Chihuahuan Desert

For more REUs, check out the NSF website.

Are the famous, sex-loving bonobos really more peaceful than their chimpanzee relatives?

Juvenile bonobo eating

Bonobos (Pan paniscus) are often referred to as the peaceful apes or the "make love, not war" apes. Previously known as the pygmy chimpanzee, they're thought of as more gentle and peaceful than their closely related cousins, the chimpanzee (Pan troglodytes). These two species are very closely related: 99.6% of their genome is the same.  Many people are aware that chimpanzees hunt other primates. You may even have heard that they will go to war against other chimps, brutally killing members of their own species, wiping out another group of chimpanzees.  With 99.6% of their DNA identical to chimpanzees, do bonobos really deserve this wholesome image?

Bonobos are only found in the Democratic Republic of Congo. They're smaller in body statue than chimpanzees but otherwise they look very much alike. In chimpanzee social systems, the males are dominant over the females. In bonobo groups, its the females who are dominant over males. Females remain in their natal unit and develop strong bonds with other females. Bonobos also play more as adults, engage in sexual activity more, and display less severe aggression than chimpanzees. So far, it looks like bonobos are living up to their reputation as the more peaceful primate.

As we learn more and more about bonobos, at least one of our original ideas about them has been proven wrong. Originally, only chimps were thought to hunt and eat other primates, but this isn't true. Surbeck and Hohmann (2008) published the first account of wild bonobos hunting other monkeys. Both males and females were active in the hunts and red colobus monkeys, black mangabeys, and other primate species were on the dinner menu for bonobos.  Seems like we've busted that myth.

Bonobos sharing food

However, a study compiling over fifty years worth of data on chimpanzees and bonobos seems to suggest that there is quite a difference. Studying 18 communities of chimps versus 4 communities of bonobos, scientists reported 152 killings by chimpanzees compared to just one killing by bonobos (Wilson et al., 2014). It is thought that differences in the brain between these two great apes may be the underlying cause behind the increased violence and aggression seen in chimpanzees. The brain of a bonobo seems to be better adapted to impulse control, perceiving stress in others. Rilling and colleagues (2012)  state that their neurology "...allows them to more strongly represent distress of both self and others compared with chimpanzees. This translates into greater empathy, as well as reduced aggression." The Rilling article is a great read, as it includes not only their findings but also a thorough overview of the behavioral differences between chimpanzees and bonobos.

To summarize, while there may not be much separating these two species in terms of their DNA, how their DNA is expressed does appear quite different. At first, scientists wondered if we simply had less data available to us on bonobos, and that lack of data meant we were missing behaviors in bonobos that are seen in chimps. (The chimpanzee population is far larger than the bonobo population.) As we study them more and more, chimpanzees come out on top in terms of aggressive behaviors.  It's important to remember through that all of these aggressive behaviors don't make up the majority of a chimpanzee's day. It's quite the opposite. Social behaviors make up a small amount of any primate's day. Feeding and resting take top priority. That said, I think the conclusion that bonobos are more peaceful than chimpanzees stands for now.


Food for thought: I think it's most surprising that bonobos will share first with strangers before they share with friends or associate bonobos (Tan and Hare, 2013). This isn't something we see with chimpanzees (and arguably something we don't see in all humans). Why would a bonobo share with a stranger first? How is this an adaptive behavior?

Check out this incredible BBC video explaining the hunting tactics of chimpanzees. (Yes, they really do have tactics.)

Read NOVA's interview with the well-known primatologist, Frans de Waal, about studying bonobos.

Journal articles referenced:
Surbeck, M., & Hohmann, G. (2008). Primate hunting by bonobos at LuiKotale, salonga national park. Current Biology, 18(19), R906-R907. doi:10.1016/j.cub.2008.08.040
Wilson, M. L., Boesch, C., Fruth, B., Furuichi, T., Gilby, I. C., Hashimoto, C., . . . Wrangham, R. W. (2014). Lethal aggression in pan is better explained by adaptive strategies than human impacts. Nature, 513(7518), 414. 
Rilling, J. K., Scholz, J., Preuss, T. M., Glasser, M. F., Errangi, B. K., & Behrens, T. E. (2012). Differences between chimpanzees and bonobos in neural systems supporting social cognition. Social Cognitive and Affective Neuroscience, 7(4), 369-379. doi:10.1093/scan/nsr017
Tan J, Hare B. Bonobos Share with Strangers. PLOS ONE, 2013; 8 (1): e51922 DOI: 10.1371/journal.pone.0051922