Tag Archives: pokemon

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?

Slowbro and Shellder – Mutualism, Commensalism, or Parasitism (Symbiotic Relationships)

One day you’re walking along a beach  and you stumble across a docile Slowpoke fishing with its tail, a common method of hunting as it allows slowpoke to sit around lazily will its food comes to it. The sweet juices found in its tail is a tasty treat to other Pokémon (as well as humans according to the events of Generation II). Suddenly the Slowpoke flinches, you watch as it hauls its tail to find not a fish but a bivalve locked into its flesh – a Shellder. The Slowpoke gives you a blank look of surprise before its body disappears in a glow and before your eyes it evolves into Slowbro, who now stands upright and appears more aware than before. The Shellder too has also undergone physiological transformation, its color has changed to a dull grey and its shell resembles that of a mollusk more than a bivalve, outfitted with spikes for added protection.

You, the astute Pokébiologist, recall that many Pokémon group together in order to evolve – Magnemite form groups of three in order to become a Magneton, two Beldum fuse together to form a Metang, and two Metang combine to form a Metagross. But those instances only involved Pokémon of the same species, here we have one Pokémon interacting with a completely different Pokémon to trigger a dramatic transformation for both creatures. Moreover, each Pokémon retains its own consciousness as far as you can tell, they remain separate entities that are merely working in unison. The geneticist side of you suspects the work of epigenetics (see Eevee Epigenetics), but you are an ecologist at heart and recognize immediately the symbiotic relationship between the two organisms.

In nature, organisms will often interact with each other, as it is difficult to avoid contact with other living things even if you tried. Something as seemingly innocuous as stepping on a blade of grass is a interacting with another organism. We often classify these various interactions by how the organisms involved are affected. Predation, for example, involves the consumption of one organism by another organism, providing nourishment to one while ending the life of the other. However, not all interactions are as grim. In some circumstances, organisms will interact to the benefit of one or more parties, usually. This close and long-term relationship between two organisms is referred to as symbiosis, and can come in three forms, in which the organisms in questions either work harmoniously together (mutualism), harmlessly mooch off the other (commensalism), or completely exploit one to its detriment (parasitism).

In regards to Slowbro and Shellder, defining their relationship is a matter of determining which parties benefit, and which are harmed. This may seem a simple task but when dealing with the world of Pokémon things can become complicated quickly. In our own world, nature has a bad habit of not falling into the cookie-cutter labels we create in order to organize its chaos, and that is perhaps even more true for the Pokémon World.

 

An Honorable Mention: Amensalism

WomanWalkingOnGrassinWhiteDress900-850x522

No organism is an island, even an act as simple as walking across a field counts as an interspecies interaction.

Amensalistic relationships are present throughout the natural world, and it is perhaps because of its prevalence that it is often left out of most textbook discussions on symbiosis. Amensalism can be defined as a relationship in which one party is unaffected while the other is harmed and somethings straight up obliterated. In truth, its classification is merely a technicality of the relatively broad definition used for symbiosis, which at one point was strictly limited to mutualistic relationships. Essentially, every organism is involved in an amensalistic relationship, and thereby kind of negates any purpose in highlighting it as its own relationship. Refer back to my previous example of you stepping on a blade of grass. That is an amensalistic relationship, the grass you crush is greatly inhibited, perhaps even killed, while you continue unaffected and unaware of the interaction you’ve just had. Obviously, Slowpoke and Shellder are both greatly affected, which immediately rules out amensalism, but I thought it warranted mentioning.

 

Commensalism: The Boring One

Commensalistic relationships are basically a step up from amensalism, one party benefits while the other remains relatively unaffected, neither helped nor harmed. These relationships are rather uneventful (hence the title), and are usually limited to interactions where one organism use another for transportation or housing. For example, mites will often occupy different organisms such as flies for transport, never feeding off of them or causing bodily harm. Some organisms will even use the body of another postmortem for housing, such as when hermits use the shells of deceased gastropods for homes.

musc14

Free rides are hard to find, both in life and in nature.

Returning back to the Slowbro-Shellder Interaction, it’s fairly clear that Slowbro is indeed being harmed by Shellder biting down and remaining attached to its tail. Although, one could argue that Slowbro isn’t being harmed since, according to the Pokémon Silver Version PokéDex, “Naturally dull to begin with, it lost its ability to feel pain due to Shellder’s seeping poison.” However, just because an organism cannot feel the harm being inflicted upon it, does not mean it is not being harmed. Leeches release an anesthetic when they feed, allowing them to feed unnoticed by the host for hours until full. If I were to inject my sleeping roommate with an anesthetic, then stab him repeatedly in the gut as I tried to remove his kidney to sell on the black market, you would say I was harming even if he didn’t feel a thing. Not that I would ever do such a thing…

So case closed then. Slowpoke is very clearly being harmed. Shellder is a parasite. So we can completely rule out mutualism as well, right? Well, things are more complicated than that.

 

Parasitism: Violent Exploitation in the Natural World

Contrary to popular belief, parasites do not kill their host, or at least they do not intend to kill their host. You see, the parasites are locked in a special kind of symbiotic relationship, in which they derive sustenance from their host and thus will do everything in their power to keep them alive. If the host dies, the parasite will die most likely unless they can find a new body to mooch off of. That’s not to say that parasites won’t give the host a rough time, often the presence of a parasite can be debilitating to the host, perhaps killing them slowly rather than right then and there. This can be done through a number of methods – depriving the host of nutriments to feed itself, releasing waste products that can have deleterious effects to the host’s body, physically burrowing into and altering the structure of organs and tissues. In short, the fitness (survivability) of the host is sacrificed in order to advance the fitness of the parasite. The host could be on the brink of death but as long as the parasite can continue to survive, the relationship will continue.

Often when a parasite does kill its host it is either to fulfill a reproductive need, such as the lancet liver fluke which infects ants and compels them to hang to the ends of grass to be eaten by rabbits so to continue their life cycle, or it has accidently infected the wrong organism, one that has not evolved the immune defenses to keep it alive and functioning, as is the case with most fatal diseases that make the jump from animals to humans.

img_7960

Ants are not the only victims of mind control, liver flukes influence the behavior of other organisms, including snails.

As we determined earlier, Slowbro is indeed harmed by the presence of Shellder, and Shellder does increase its fitness significantly attaching itself to Slowpoke, not only giving it free transportation, but also free food from feeding off of Slowbro’s scrapes, as well as the juices that run from its tail. Even the Bulbapedia page that I’ve pulled the PokéDex entries from states in the origins that “Its parasitic relationship to Slowpoke may be inspired by leeches.” So there you have it, confirmation from the top source of Pokémon information.

However, I have come to a different conclusion.

We must recognize that nature will not always fit so easily into the boxes we’ve constructed for it. Scientist often find trouble correctly labeling symbiotic relationships, perhaps at first seeing one as purely commensalistic only to later find that the other organism is being helped in some way. This gets even messier when trying to apply real-world logic to a videogame, a videogame that isn’t even consistent with its own rules and logic, as despite its various PokéDex entries, Slowpoke’s in-game evolution into Slowbro is completely independent of any interaction with Shellder.

Yes, Slowbro is harmed by Shellder, but I would argue that it is also helped, that Slowbro’s fitness increases when “infected” by Shellder.

 

If Ticks Gave Us Superpowers: Mutualism

The faint glimmer of hope that the natural world isn’t all doom and gloom is mutualistic symbiosis, an interaction between two organisms in which both parties benefit from the relationship. This reciprocal altruism often increases the overall fitness of both individuals, a great example can be found with the mutualistic relationship of sea anemones and hermit crabs – which are also an inspiration for Slowbro’s design. In the wild, certain species of hermit crabs attach sea anemones to their shells. In this relationship, hermit crab’s fitness increases by having an additional defense against predators – an array of stinging tentacles protruding from its back. Likewise, the sea anemone’s fitness also increases, as it is not only mobile (a great advantage for a normally sedentary species), but can also feed off the scraps if the hermit crab’s food (much like a certain grey-shelled Pokémon we know).

2240003823_4579086f34_z

The sea anemone gets a free ride, the hermit gets added protection. Everybody wins!

In the previous section we have already accepted that Shellder is harming Slowbro, that part is indisputable. But I would argue that Slowbro is helped more than it is harmed in its relationship with Shellder.

Firstly, Slowbro’s stats improve significantly upon evolution via Shellder, even more so when Mega-Evolved. Now, one could chalk thus up to simple game mechanics and claim that this increase in stats is not unique to Slowbro, and they would be right. However, Slowbro does undergo additional changes in its physiology and behavior. As Slowpoke, it walked on all fours, but now with Shellder attached it can stand upright. Additionally, it receive additional powers from Shellder’s attachment, as the Black and White PokéDex states, “Though usually dim witted, it seems to become inspired if the Shellder on its tail bites down.”

Lastly, I point to my final piece of evidence – Slowking. This often forgotten secondary evolution of this docile Pokémon also falls victim to Shellder’s parasitism. However, Slowpoke only evolves into Slowking when Shellder bites down on its head, giving the once seemingly senile Pokémon an ability few Pokémon outside of legendries have – speech. In fact, Slowking gains full human-levels of intelligence by simply donning a Shellder cap.

Conway_Slowking_Psychic

“Slowking undertakes research every day in an effort to solve the mysteries of the world. However, this Pokémon apparently forgets everything it has learned if the Shellder on its head comes off.” – Pokémon Ruby and Sapphire Versions

Slowking undertakes research every day in an effort to solve the mysteries of the world. However, this Pokémon apparently forgets everything it has learned if the Shellder on its head comes off.

Classified as the Royal Pokémon, Slowking also stands upright, and has intelligence comparable to award-winning scientist, even conducting scientific research. Think about it, a Pokémon is doing scientific research and publishing papers. A small reminder that moments ago this same Pokémon was sitting by a body of water, too lazy to hunt for prey and merely fishing with its tail hoping that it something will bite.

The secret seems to lie within Shellder’s venom, whose effects increase the mental abilities of Slowpoke, producing a moderately more adept yet still docile organism in Slowbro when just attached to the tail, and an intelligent being when latched directly above the brain as is the case with Slowking. Either way, the overall fitness of Slowpoke is increased significantly, ranging from just being able to obtain food more easily to literally becoming self-aware.

Thus, while Shellder may harm Slowbro initially, the perhaps unintentional effects of its venom on its host indeed brings a plethora of benefits to Slowbro and Slowking. It is neither strictly a mutualistic nor parasitic relationship, but an odd hybrid of the two. In our world, it would be like if ticks gave us superpowers when they feed on you, instead of Lyme disease.

The Slowpoke line is a fascinating line to study, and provides great insight on the various interactions between Pokémon species that the games don’t often shed much light into. But with a little over analysis and speculation, we can make some sense of this, at times often, senseless world.

Azurill – The Hermaphrodite Pokémon

At first glance, Azurill may seem like another forgettable baby Pokémon. This poor water mouse is easily overshadowed by its evolved forms – Marill for igniting the myth that became Pikablu, and Azumarill for its use in competitive play. Indeed, the only memorable characteristic about this Pokémon is its frowning sprite, probably begging to be put out of its misery for being relegated to Gen II dex filler. However, do not let that incredibly heart-wrenching face fool you, because Azuril does have one thing that sets it apart from the other 721 Pokémon currently in existence. Azurill, upon evolution, can change its gender. Azurill is a hermaphrodite.

Until Generation VI when this was fixed, Azurill had a gender ratio of 75% female and 25% male, while both Marill and Azumarill had an even 50:50 split between male and male. Thus, upon evolution into Marill, female Azurills actually had a one in three chance of swapping gender and evolving into a male Marill. Imagine the surprise of the unsuspecting player to find out the female Azurill they had raised and probably given a gender-appropriate name was now a male.

In biology, this phenomenon is referred to as hermaphroditism, and an organism that has both the reproductive organs of both the male and female sexes is a hermaphrodite. This trait is most common in invertebrates such as gastropods, earthworms, and jellyfish, as well as flowering plants.

Hermaphrodites fall into two categories – simultaneous and sequential. Simultaneous hermaphrodites continuously bear male and female reproductive organs throughout their lives. Garden snails are a well-known example of simultaneous hermaphroditism. The snails still mate and produce offspring that are genetically unique, however self-fertilization is not uncommon for simultaneous hermaphrodites, as plants often self-fertilize in the absence of pollinators. Some organisms such as earthworms have defenses in place to prevent self-pollination.

440px-Snails_mating.jpg

Snails exchanging sexual material. The longer you stare at it the less disturbing it becomes.

 

The world of simultaneous hermaphroditism is a fascinating if not strange place, as evident by the unsettling number of photos of invertebrates in various stages of copulation I’ve been forced to shuffle through in order to write this blog post. But personally, I find the sequential hermaphrodites more interesting, in that they are born as one sex but later switch later in life.

A creature such as Azurill, would be classified as a protogynous hermaphrodite, an organism that was born female but changes to a male. Protogyny is common among fish, some of the few vertebrates that exhibit hermaphroditism. Female wrasses, for example, may change into males upon a shortage of the opposite sex, developing testes in place of ovaries. However, this change is irreversible, and only females can make the change, although, under laboratory conditions, males have been known to also swap genders.

lineatus-fairy-wrasse-cirrhilabrus-lineatus-lined-fairy-wrasse-3

Wrasses often organize into “harems” in which mating typically takes place.

 

Azuril appears to fall into the same boat of the wrasse, with females being the only ones able to change gender, as well as it being an irreversible process. While the in-game cause of this phenomenon may lie in perhaps an oversight on the game designer’s part, from a pure evolutionary viewpoint, Azuril’s hermaphroditism could provide a similar benefit as the wrasse, balancing out the gender ratios when they fall out of whack. But that’s just me applying real world logic to a videogame, again.

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!

Exeggutor: A True Freak of Nature

The Pokémon World and our own world are similar in that the natural processes that govern life produce some strange creatures. Perhaps one of the most odd (and unsettling) is Exeggutor, the dual Grass Psychic-type that wanders around with its three grinning coconut heads resembling some unholy hybrid between a palm tree and several stoners. Yet our anthropomorphic palm tree friend is quite the interesting specimen when put under the lens of real-world biology.

 

A Free-Thinker of Many Heads

The most obvious abnormality of Exeggutor at first glance are its three heads, each with their own distinct and unsettling facial expression. According to the PokéDex entry in Pokémon Gold Version, “Its three heads think independently. However, they are friendly and never appear to squabble.”

This leads to quite the impressive nervous system, especially for a plant. But quips about plants not having any neurons aside, it is not unfounded in nature for animals to have multiple “brains” per say. For instance, octopi have nine brains, the main brain being located in its head with eight auxiliary brains in each of its eight tentacles. When an octopus desires to operate one of its arms, the main brain sends a single message to the nerves located in its arms, and then the arm “brain” proceeds to carry out the order all on its own. Even when severed, an octopus arm will still respond and react to stimuli the same way it would if it were attached to the complete organism and main brain1.

42-25125512.jpg__800x600_q85_crop

Due to the complexity of their nervous systems, many people have a moral objection to the consumption of cephalopods.

 

However, unlike Exeggutor, the auxiliary brains of an octopus do not have their own consciousness. A severed octopi arm does not a new octopus make.

A particularly fascinating condition is that of polycephaly. A polycephalic organism is born with two or more heads, either as a supernumerary body part or as completely separate beings sharing a body, as the case is with Exeggutor. Usually the result of faulty twinning, polycephaly never results in more than three heads (tricephalic), with two being the norm (dicephalic). Unfortunately, in both humans and animals, dicephalic organisms rarely survive, as the two heads will often fight with each other for control over the body, often becoming disoriented, which makes for difficulty in fleeing predators. Polycephalic snakes have been known to even attack and consume their other head. Thankfully, Exeggutor appears to be a peaceful organism and its heads are very cooperative, as “they never appear to squabble”.

two-headed-snake-03

Those that handler polycephalic organisms often report having to place a barrier between heads in order to prevent one from eating the other during a feeding.

As deleterious as this condition may be in our world, the trait seems to be of advantage in the Pokémon World. In the Crystal Version PokéDex, “Living in a good environment makes it grow lots of heads.” Apparently the selection pressures of the Exeggutor’s ecosystem make it so that having multiple heads is an advantage, running completely counter to our world which usually follows a general rule of the more appendages an organism has to manage the more energy required to maintain them all. In the game of evolution it’s all about the costs and rewards, having an extra head or two is just too taxing and hardly reaps any benefits.

While selection of polycephalic individuals may seem paradoxical at first, there is good reason for the Coconut Pokémon to expend energy growing its extra heads, and the answer lies with the endgame of survival, arguably the purpose of life – reproduction.

 

Dropping Heads: Clonal Fragmentation

Counter to what is portrayed in the videogames, Exeggutor does not need another Exeggutor (or any Pokémon of its egg group) to reproduce. In its natural environment, when not forcibly bred by overanxious trainers eager to create an IV master race, Exeggutor can reproduce asexually simply by parting with one of its heads.

250px-103Exeggutor

“If a head grows too big, it falls off and becomes an Exeggcute.” – Diamond/Pearl/Platinum PokeDex

More specifically, Exeggutor appears to reproduce through clonal fragmentation, a form of asexual reproduction most common in flatworms, sponges, annelids, sea stars, as well as mold, lichens, types of cyanobacteria, and many plants.

The process of fragmentation involves a piece of the organism splitting off to regenerate into a complete organism that is also able to reproduce. For example, tapeworms live in the digestive tracks of mammals, usually dogs and sometimes humans (either intentionally or, depending on the type of person, on purpose). As you can imagine finding a mate in the middle of a dog’s small intestine can prove troublesome, but all a tapeworm has to do is release an end segment of its own body down the track, and with some time Rover will have an infestation of new tapeworms, grown from the end bits of the original pioneer that first ventured into his bowels.

D. caninum ex dog.  Given by Peter Schantz

If you find one of these segments in your pet’s feces (or your own), seek medical attention.

As is common in binary fission, this often results in the regenerated fragment being genetically identical to that parent, making all Exeggutors clones of each other, the regenerated offspring of past Exeggutors whose heads grew too large to support. However, this process, as is the case with most forms of asexual reproduction, does have one major drawback, in that since all organisms are effectively clones of each other, there is no variation, and as any good biologist (or PokéBiologist) knows, genetic variation is the driving force of natural selection and therefore evolution. But this shouldn’t be a problem for Exeggutor, they seem to be plentiful enough, and pending an Exeggutor superbug, they will continue to endure for many generations to come.

Of course, there is the unique caveat that with Exeggutor, a single fallen head does not a new Exeggutor make, rather the individual Exeggcute have to swarm together, usually in groups of six in order to eventually “evolve” into an Exeggcute. Communicating telepathically, these eggs seem to form somewhat of a superorganism…but that is a topic for another day.

 

Cited Sources

http://news.nationalgeographic.com/news/2001/09/0907_octoarm.html

Kangaskhan – Parental Bond and Parthenogenesis

Ever since its introduction in the Second Generation, the concept of Pokémon breeding, while greatly appreciated, has spawned a plethora of questions, including, but by no means limited to – how can completely different species successfully copulate? How can they produce fertile offspring that are functional and not riddled with genetic malfunctions? Why is a tiny little cat able to have sex with literally the largest Pokémon known to us thus far? Perhaps one of the largest contributors to this pool of questions is Kangaskhan, a species that is 100% female and is born already equipped with a baby in pouch.

There is much to be said about the Parental Pokémon, aptly named since it literally enters the world a mother. It comes as no surprise that its design is inspired by the kangaroo, yet there is so much more to learn from her. Indeed, Kangaskhan is more than a magical marsupial, she is a shining example of the remarkable process that we in our world know as parthenogenesis.

 

A World Without Men

Time to have a talk. The Talk to be precise.

Excuse me if my heteronormative bias shows here but typically speaking, a man will encounter a woman and either through coercion or brute force insert his penis into her vagina and deposit his half of the reproductive materials via ejaculation. His materials, commonly known as sperm, enter the vagina, with a few lucky individuals making it past the cervix to – if this woman he has taken is ovulating – join with a nice plump egg waiting to be fertilized. The first sperm to penetrate its outer membrane wins the prize of fusing with the ovum to form a zygote and nine months later a baby is born.

We call this process sexual reproduction and it requires the existence of two sexes at minimum (though there can be more in some cases) since its main selling point is the promotion of diversity. Like a college admissions department, diversity is the name of the game when it comes to genes. More variation means more unique individuals with traits that may or may not prove advantageous in life. However, sexual reproduction is not the only way to make a baby.

If diversity is not really your interest and you’re just looking to pass on your legacy without the energy and drama that comes with sex, asexual reproduction may just be what you’re looking for.

In asexual reproduction, no new genetic material is added. The next generation is genetically identical to that before it with no variations other than the random mutations that still occur during DNA replication. Naturally, this leads to severe lack of diversity with very few, if any, differences between individuals, but has the benefit of not needing to expend energy in courtship and actual mating. Additionally, asexual reproduction only requires one sex.

There are many forms of asexual reproduction – budding, binary fission, clonal fragmentation. But perhaps the most interesting form is parthenogenesis, essentially virgin birth. Offspring of parthenogenic organism develop from unfertilized eggs. Most organism that use parthenogenesis do have two sexes, as well as the ability to reproduce sexually, and often fall back to it when conditions become adverse and the diversity is needed1. However, there are some species, such as Kangaskhan, that have abandoned the entire male line in favor of an all-female feminist utopia.

Take for example Aspidoscelis uniparens, the whiptail lizard, a species that contains no genetic males and reproduces completely through parthenogenesis. Oddly enough however, the females of this species do engage in mating rituals similar to that if they were reproducing sexually which enhances ovulation. Furthermore, despite being asexual, whiptails have managed to find a way to preserve some degree of genetic diversity through combining sister chromosomes instead of homologous chromosomes2.

whiptail-lizard-672x372

A conservative’s worst nightmare — a society of promiscuous female lesbians with no male supervision.

 

It appears that Kangaskhan has taken a similar evolutionary path to the whiptail lizard. Being a male-free species can have its benefits especially for a creature as devoted to its young as Kangaskhan. The PokéDex entry in Emerald appropriately states, “If you come across a young Kangaskhan playing by itself, never try to catch it. The baby’s parent is sure to be in the area, and it will become violently enraged.” With sexual reproduction comes competition between not only the sexes but between competing males, each vying for a womb to continue his genetic legacy, and children are often the first casualties in this war, as it is not rare for a male to kill the offspring of another male so to ensure his are the only ones that end up surviving. With Kangaskhan’s identity wrapped up in protecting its baby, a sexual society would prove troublesome, male Kangaskhan mutilating babies while forcing fertile females into copulation. A better situation could be created without the presence of males, one in which the young are protected and mothers rested easily without the threat of a male high on testosterone killing her child.

 

Parental Bond: More than an Ability

Perhaps more than any other class of animals, mammals have mastered the art of motherhood. Few other organisms take on the burden of reproduction to the extent that mammals do. From the moment of conception, the mammalian mother is dealt with the burden of having to carry and support what essentially boils down to a temporary parasite that drains off its energy over whatever period of gestation it takes. Then after the offspring has been born they are still tasked with the job of providing additional nourishment through a unique little gland named mammary (yes, that’s where mammal comes from), in doing so providing them with invaluable proteins, antibodies, and other goodies that’ll help them later in life.

Woman_breastfeeding_an_infant

In humans, oxytocin is released in females during breastfeeding, further forging the bond between mother and child.

But for marsupials in particular, motherhood comes with some additional stakes. A joey (baby kangaroo) is born early in its development, with a gestation of only 30-36 days. The pink gooey bundle of joy resembles its distant cousin the gummy bear more than a kangaroo at this stage in its life, being no larger than a lima bean. Being basically a living fetus, the joey is especially vulnerable in these first months. However, it quickly climbs to the pouch with its barely formed forelimbs and latches on to its mother’s teat where it will reside for the next nine months, feeding on its mother’s milk from the safety of the pouch.

baby-animals-who-look-like-nothing-like-their-parents-7

You will never eat a gummy bear ever again.

 

 

One can imagine that it can get crowded quickly in a pouch. Thankfully, kangaroos have evolved a unique adaptation called diapause, in which a mother essentially freezes the development of an embryo while her pouch is occupied. Once the joey is old enough to leave the pouch for good, the embryo is allowed to continue its growth, thus allowing the kangaroo mother to allot all of her attention to the primary offspring on hand.

This being considered, I find it interesting that in Kangaskhan’s Mega Evolution, the vigilant mother finally lets her current joey from the safety of her pouch to fight side by side with her, herself unchanged by the actual Mega Evolution but her young larger and more plated, starting to resemble its adult form. Perhaps this particular event is more than just temporary battle effect, but the release of Kangaskhan’s current joey and the unpausing of diapause, in which the joey that resides in her pouch post-Mega Evolution is not the same joey that was in battle but the newly developed embryo grown into a joey after months of diapause.

 

 

Cited Sources

COLIN BLAKEMORE and SHELIA JENNETT. “parthenogenesis.The Oxford Companion to the Body. 2001. Encyclopedia.com. 15 Mar. 2016 <http://www.encyclopedia.com>

Lutes, A. A., Neaves, W.B., Baumann, D. P., Wiegraebe, W., Baumann, P. (2010). Sister chromosome pairing maintains heteroozygosity in parthenogenetic lizards. nature.com.

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