AP Biology class blog for discussing current research in Biology

Tag: darwin

Mirror Mirror On The Wall, Can Animals Recognize Themselves At All?

Eat. Drink. Excrete. Sleep. Repeat.

We humans often reduce the lives of animals to these common processes. However, scientists in recent decades have broadened the horizons for animals by looking into their ability to self-recognize.

Developed in 1970 by psychologist Gordon Gallup Jr., the mirror self-recognition (MSR) test has been the most common method of testing animals’ awareness of themselves.  The test entails the placement of a red spot on a sedated animal in a location which the animal cannot see without a mirror.  The spot must be smooth and odorless as to not excite any olfactory or tactile cues. Once the sedation wares off, the animal is presented with a mirror.  If the animal makes a movement towards the red spot, the test makes the assumption that the animal recognizes itself.  Most species tested have failed the MSR exam with only great apes, an individual Asiatic elephant, orcas, dolphins, and Eurasian magpies passing as of 2016.

The mirror test - a Baboon looking at at his own reflection

Baboon observing itself during MSR test by Moshe Blank, source

However, the “red spot” test has come under scrutiny with many scientists claiming that it is not a true indicator of self-recognition.  For the exam to be applicable, one must make the assumption that animals know the reflective properties of a mirror, an object which they may have never seen before. Additionally, many animals (especially wild one’s) do not have a clue as to what they look like as an individual. Rather than visuals, they can often recognize certain smells and sounds. Marc Bekoff, professor emeritus of ecology and evolutionary biology at the University of Colorado Boulder, conducted “yellow snow” experiments in which he deducted that his dog Jhetro could recognize its own urine and would respond differently when presented with the urine of other dogs.  “Animals such as Jethro may fail the red dot test but still possess some sense of self or ownership over their body and smells.”

Strengthening the case against the MSR test, naturalist legend Charles Darwin claimed in his theory on evolutionary continuity that the differences among species come in degree, not kind.  This means that if humans are self-aware creatures, other animals are most likely self-aware as well but to a different extent.

Although animals may not have the same reaction when looking into a mirror as humans do, most creatures understand that they possess their own body which does not belong to another.  For example, animals must know the placement of their bodies in space to effectively navigate as a pack or flock. Lastly, one can look to his/her four-legged friend on the floor to see how animals display ownership over food, territory, family, and body parts with which they associate.

So, can animals really recognize themselves?  Yes, they can.  Just not always in the same ways humans do.

This area of research opens up the gates to even more complicated questions about animals.  How do different species think and feel? How do they grapple with emotion?

Island Lizards More Tame

A study conducted by a team of researchers from the University of California, Riverside, Indiana University, Purdue University, Fort Wayne, and George Washington University showed that lizards from islands are more calm then ones from mainland regions. The researchers established this by comparing the flight initiation distance, or distance before a prey starts to flee when approached,  between various lizards. The researchers were able to approach island lizards more closely then mainland lizards. The study was inspired by a long-time debate that island animals were more “tame” that started with an observation by Charles Darwin when he visited the Galapagos Islands. He felt that because these islands were scarce of most predators, those animals which did not waste energy fleeing unnecessarily would have a better chance of survival. All of this being said the findings were inconclusive.There are many variables that factor in to flight initiation distance and can not be categorized by where a creature lives. Reptile_tx_usa

Dear Darwin: What Makes Ryan Reynolds “Sexy”?

Photo Credit: Paco Paco Flickr

Now we all know that a big jaw, prominent brow, and bulging muscles are conventionally thought of as attractive features in a man and that large breasts, an hour-glass figure, and big eyes are attractive in women, but have you ever wondered why?

Well the answer lies in an unexpected place: science. According to the Evolutionary Theory of Attraction, what men and women  perceive to be attractive is actually based on adaptational behaviors that traditionally helped survival. Studies show that women look for masculine features such as a defined jaw, prominent brow, and muscular build because these often to reflect physiological and behavioral traits such as strength, aggression, virility, and a strong immune system, which would be advantageous to pass on to offspring and would mean that the man can provide and protect his family.

So while women’s attraction is rooted in a man’s ability to provide for his family, men on the put more emphasis on signs of fertility and youth. The hour-glass figure: large breasts and “child-bearing” hips, and youthful features such as plump lips, a hip-to-waist ratio of 0.7, a face with a high forehead, good skin, and big eyes are signs to men that the prospective mate is fertile and young. Such features helped ensure the male that his genes would be passed on to his offspring. Other factors such as symmetry, especially facial symmetry, is attractive because it means that there are strong genetics at work according to researchers and experts.

Recent studies show that when a woman chooses a mate, often times she must subconsciously choose between a macho man and his more wimpy counterpart depending on her situation. While the macho man has preferential genes to pass on to offspring, these traits often mean tendency to abandon, hostility, and promiscuity. The less masculine man is more likely to provide the stability, love, and care for a family. In fact, according to expert, Dr. DeBruine’s study, a woman’s environment greatly plays into her attraction between these two types of men. In her study on women in countries with poor health standards, women preferred men with more masculine features more than those who lived in more stable and healthy societies. This is a classic example of natural selection because the women look for healthier genes often associated with masculine, macho attractive men.

So that is why we find movie stars like Angelina Jolie, Brad Bitt, and Ryan Reynolds are attractive: evolutionary adaptations meant to help ensure our survival and the successful passing on of genes to offspring. Do you agree with this theory of attraction? And which category would you put yourselves in ladies, those who go after Mr. Sensitive or those who go after Mr. Dangerous?


For more on this go to:—Evolutionary-Theory&id=2236366

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