Tag Archives: Pokemon X and Y versions

Sexual Dimorphism in the Pokémon World

First introduced with Nidoran in Generation I, and later expanded to other Pokémon in Generation IV, gender differences have greatly enriched the playing experience of both casual and hardcore players alike. Of The 720 Pokémon currently in existence, 109 exhibit some form of variation between the sexes, ranging from subtle differences in design such as female Pikachu’s heart-shaped tail, to more obvious differences like male and female Meowstic of the current generation.

pikacosplay2

The inclusion of such differences is a nod to the real-life phenomenon of sexual dimorphism, which describes the differences in appearance between males and females of the same species. These differences can include color, shape, size, secondary sex characteristics, and even certain behaviors.

Perhaps the most well-known example of sexual dimorphism is of the peacock and peahen. Male peacocks exhibit spectacular coloration and ornamentation with their elaborate tails and colorful plumage, while female peahens are rather plain and inconspicuous. However, the astute biologist (or PokéBiologist) will point out an important detail, that while the male’s tail may be great for attracting a mate, from an evolutionary perspective, it appears to be of great hindrance, not only inhibiting its ability for flight but also making it a clear target for predators. So the question is, how did such a trait arise if it puts the male at a disadvantage and how does it remain fixated in the current gene pool?

difference-between-male-and-female-peacocks-wallpaper-1

The answer, my friend, is sexual selection, the primary cause for sexual dimorphism. In a way, sexual dimorphism itself is a byproduct of these sexually selective pressures, which favor certain traits over others in the mating process. In his book The Red Queen: Sex and the Evolution of Human Nature, Matt Ridley remarks that, “Sexual selection theory suggests that much of the behavior and some of the appearance of an animal is adapted not to help it survive but to help it acquire the best or most mates.”

For birds and mammals, the burden of reproduction usually falls more heavily on the female than the male. For a female, reproducing comes with many upfront costs such as expending time and energy guarding an egg or carrying a developing organism for an entire gestation, in addition to the care that said offspring requires after birth/hatching. Males on the other hand, typically are not as involved and can indiscriminately disperse their seed without worry. Thus, females must be more selective with whom they mate with, resulting in a dynamic where it is often the males that are colorful and ornamented while the females remain plain, as this pressure does not apply to them.

521Unfezant

This principle even extends to the Pokémon World, such as with Unfezant of the Unova Region.

 

Returning back to the example of the peacock, while the tail may not aid in its survival, it does have the major benefit of attracting a mate. A male that wasn’t as flamboyant may be able to evade predators more easily, but it ultimately means nothing if they can’t reproduce. Ridley likens this to a student with testing anxiety, stating, “If a student is brilliant but terrible in examinations – if, say, she simply collapses with nervousness at the very thought of an exam – then her brilliance will count for nothing in a course that is tested by a single examination at the end of the term.”

But not all forms of sexual dimorphism follow these “traditional” gender norms. Females can often be larger than their male counterparts. This often pairs nicely with sexual cannibalism, common in arachnids such as spiders, in which the female eats her mate following copulation.

2824387_orig

Female and male black widow.

 

One particularly extreme example of this size disparity can be found in the anglerfish. For the longest time, scientist doubted the very existence of a male angler fish until it was discovered that the males they were looking for were most likely right in front of them the whole time. You see, male anglerfish are much smaller than their female counterparts. These little lads are destined to become no more than a sperm-filled wart on the side of a larger female angler fish, as they bite down on a prospective mate and gradually merge circulatory systems giving up all sense of bodily autonomy in the process.

Capturejkuio

In the Pokémon World, most cases are nowhere near as extreme as the angler fish. In fact, most seem to be on the subtler side, at least in regards to the earlier generations of Pokémon. The later generations however, appear to show more obvious dimorphism than previous ones. Unfezant, much like the real-life pheasant it was based on, displays clear dimorphism from sexual selection, with the male bearing a pink mask and bright green plumage, while the female is simpler and has plain brown plumage instead. Pyroar also takes a hint from our world, copying the dimorphism displayed between male and female lions.

However, the Pokémon that displays the most differences is hands-down Meowstic, not only having different physical features but also learning different moves. In a reversal of traditional gender norms, the female is mainly for offensive purposes, learning more attack-based moves, while the male plays a more supportive role. This dimorphism even extends to their Hidden Abilities; females have the Competitive ability while males have the Prankster ability.

12655_Meowstic-male-and-female

“When in danger, it raises its ears and releases enough psychic power to grind a 10-ton truck to dust.” – Pokémon X Version PokéDex

 

The complexity of the Pokémon World never ceases to amaze me, and this added feature makes the biology of this fictional world seem all the more real. With a new generation of Pokémon on its way, there’s no telling what types of sexual dimorphism will be presented to us next.

What’s your favorite Pokémon that displays sexual dimorphism? Leave it in the comments, and if you’re interested in learning more about sexual selection and evolution in general, I highly recommend checking out Matt Ridley’s book The Red Queen: Sex and the Evolution of Human Nature. It’s a great read if you’re a biology nerd like me, and even if you’re not it still has some fascinating insight on the evolution of human sexuality, and who doesn’t like sex?

Advertisements

Eevee Epigenetics – A Tale of Phenotypic Plasticity

The term Eeveelution bugs me. Scratch that. The term Eeveelution makes my blood boil, the very utterance of its syllables causes every brain cell in my body to go into apoptosis. I already have issues with the fact that the in-game process known as Pokémon “evolution” is nothing of the sorts and is actually closer to metamorphosis in most cases. But this word that the Pokémon fandom has adopted for Eevee is even more misleading.

Eevee does not evolve.

In fact Eevee hardly changes at all.

At a very fundamental level, your dear Vaporeon is still an Eevee, granted, with some obvious differences. But these additions to your Pokémon’s physiology are not due to evolution, but to the power of phenotypic plasticity.

All life (as we know it) speaks the same language, the complex yet elegantly simple language of deoxyribonucleic acid, know more commonly as DNA. Its alphabet is composed of only four letters – adenine, guanine, cytosine, and thymine. Together these four nitrogenous bases order themselves in countless sequences to form the instructions for life. First, DNA is transcribed into messenger ribonucleic acid (mRNA). From there, the mRNA is delivered to a sort of protein factory called a ribosome where – to greatly oversimplify things – the mRNA is used to code for various proteins which are what do the real magic. Thus is the way life continues – from DNA to RNA to protein, the Central Dogma of Biology.

central_dogma

The Central Dogma of Biology

 

However, in some organisms there lay regions of “silent” DNA that are highly methylated, or in other words, are wound up too tightly to be transcribed, and thus remain quiet and unused. But, there are ways for this silent DNA, or heterochromatin, to unravel and be transcribed.

Without altering any of the nucleotides, an organism’s phenotype can change dramatically through epigenetics, the external modification of DNA. Once that silent heterochromatin is demethylated, the DNA can transcribed and the central dogma can continue, the resulting proteins being expressed as a new phenotype.

A great example can be found in bees. All bees essentially are born with the same genotype, with the vast majority destined to become workers as long as no external forces act on them. But a select few during the larval stage are fed a special food called royal jelly, which demethylates the silenced DNA in the bee larvae and allows transcription of the once silent region to begin. This particular gene sequence happens to be especially important, for it allows for the development of ovaries in place of the normal pollen sacs that a worker would grow. The larvae raised on royal jelly unsurprisingly grow to become fertile queens and allow for the continuation of the species.

main600x0_p183ogivilc971dscs6n1m5pgq4

Honey and beeswax are not the only bee products that humans can use, royal jelly actually has nutritional benefits as well.

 

A similar phenomenon appears to occur in Eevee. Regions of Eevee’s genome remain silent until otherwise activated upon the right external stimuli. For the Generation I species, the phenotype is dependent on exposure to a specific elemental stone – Water Stone yields a Vaporeon phenotype, Fire Stone Flareon, and Thunder Stone Jolteon. In Generation II such epigenetic change is dependent on two factors, friendship and the time of the day. Night gives you an Eevee with an Umbreon phenotype, and day produces an Espeon one. Leafeon and Glaceon work similarly to Gen I, with exposure to a specific rock being the determining factor. And lastly Sylveon, who requires great affection to achieve its phenotype, an act similar to how rat mothers lick their pups in order to activate the genes that boost their immune system.

At the end of the day, it’s still an Eevee, despite what those other fallacious Pokémon “professors” claim, rather, each variation of Eevee is simply displaying a different phenotype triggered by the demethylation and subsequent transcription of once silent regions of DNA. After all, the PokéDex constantly repeats how irregular and plastic Eevee’s genes are. Perhaps those irregularities are due to all the regions of silent heterochromatin lying hidden in Eevee’s genome.

PK25_Eeveelutions

Who is your favorite Eeveelution Eevee phenotype? As a swimmer, mine is Vaporeon. Post yours below!

A Dragon in Poison Skin – Goodra and Batesian Mimicry

For five glorious generations of Pokémon games, Dragon-types reigned supreme. With their only weakness being Ice and other Dragons, these creatures were unmatched in competitive play as well as in nature. They were the apex predators, sitting comfortably atop the trophic pyramid without a fear in the world.

 

That is until Generation Six rolled along.

Suddenly the game changed, as life is a constant struggle for survival, and a new elemental-type was introduced – Fairy, and in one fell swoop the hunter become the hunted. No longer could these Dragons loaf around lazily on top of the food chain, they had competition. While other Dragons crumbled and humbly abdicated the throne, one took matters into its own hands.

An isolated population of particularly rotund and bulky Dragons evolved in the region of Kalos. Heavily populated by the notorious Fairy-Types, selective pressures favored certain traits more than others, and through the power of evolution the strange gooey Dragonite rip-off we see today came into existence. At first glance one would assume that it’s the farthest thing from a Dragon, the first type that comes to mind is Poison with its purple skin and green dots all covered in a slimy mucus coat. And that, my friends, is the point.

In biology, we call this phenomenon mimicry – when two or more organisms share a superficial resemblance but are not taxonomically related1. This adaptation is often used by one species to trick its predators into believing it is another, more harmful and potentially dangerous species. Non-venomous milk snakes, for example, mimic the coral snake, a venomous species, in order to deter predators. This resemblance is achieved through mimicry of its color pattern – red touch yellow bad for a fellow (coral snake), red touch black you’re alright jack (milk snake). Although, most predators don’t have the advantage of a cute rhyme to remind them which is which and opt to stay far away from the both of them.

h9991053

Note: It’s probably best to avoid both. Just in case.

 

This type of mimicry, when a harmless species adopts the color patterns and warning signals of another, is called Batesian mimicry, named after Henry W. Bates, an English naturalist who first discovered this phenomenon in Brazilian forest butterflies of two distinct species2.

For our pseudo-legendary friend, this adaptation is vital to its survival. The region of Kalos is rife with Fairy-Types, all deadly to Dragons such as Goodra and its pre-evolutions. Its struggles become more challenging considering that Fairies have an immunity of Dragon-Type moves, which leaves most Dragons defenseless as their biggest strength is often their offensive game.

Unable to fight off the Fairies, most Dragons fall victim to their weakness and die off, but one line managed to survive.

Goodra is by far the most bulky of the Dragons, which is no coincidence. A glass cannon such as Haxorus with all its energy invested in Attack would prove useless and ultimately fatal when up against a foe who is immune to such moves. In short, Defense and Special Defense would be selected over a strong offense (though Goodra does maintain a decent offense for other Types). A similar selection would occur in regards to its coloration, as purple and green are associated with Poison-Types, and would increase the fitness of those individuals that had the trait. By mimicking this Fairy weakness, predators would be sure to stay clear of Goodra, thus allowing it to survive in a Fairy-Dominant region such as Kalos.

 

Cited Sources

http://www.britannica.com/science/mimicry