Most of the single-celled organisms in the world, like bacteria, reproduce asexually by making copies of themselves. So how did sex come to rule the animal kingdom? Scientists have been trying to figure out the origin of sex for hundreds of years, without much luck.

Asexual reproduction is more convenient and requires less effort: there’s no search for a partner and you get to pass all your genes along, from the U.K.’s National History Museum:

In many ways asexual reproduction is the better evolutionary strategy: only one parent is needed and all of their genes are passed on to the next generation.  All bacteria, most plants and even some animals reproduce asexually at least some of the time.
Sex is less efficient. Finding a mate can take time and energy, and any gametes that aren’t fertilised go to waste. Plus, each parent only passes half of its genes to the offspring.

But 99 percent of multicelled animals use sex to reproduce. They form gametes, mix those together and create progeny with an entirely new genome.  Scientists have long wondered what processes caused sex to evolve and become so incredibly prevalent in the animal world.

Most hypotheses about the evolution of sex point out that when genes are mixed between individuals sexually, bad genetic mutations can be eliminated more quickly than in asexual reproduction. But, since the 1880s, scientists have been unable to prove one hypothesis or another explains Megan Scudellari in Scientist magazine:

In 1886, German evolutionary biologist August Weismann proposed that sexual reproduction reshuffles genes to create “individual differences” upon which natural selection acts. Additional ideas have emerged since Weismann’s hypothesis: sex rids the genome of deleterious mutations; sex rapidly introduces beneficial mutations; sex helps organisms dodge parasitic infections. Yet these evolutionary justifications for sex have remained hypotheses because there is not enough evidence to suggest that any of them provide enough of a benefit to surmount the exquisitely high costs of sex, which include the time and energy it takes to find a mate, the passage of only half of one’s genes to the next generation, and the breaking apart of favorable gene combinations.

Part of the problem, Sculdellari says, is where scientists look to try to test these ideas. Most of the organisms we know the most about sexually like flies, humans and bacteria only reproduce sexually or asexually. But there are some species that can do both depending on the environmental circumstances surrounding them. Yeast, snails and rotifers, microscopic freshwater animals reproduce both sexually and asexually. By studying these organisms, scientists can compare the relative health of their asexually and sexually produced offspring.

The Red Queen hypothesis, named after the Alice in Wonderland character, suggests that sex is really about eliminating the chance of disease through the exchange of cell surface genes that alter the proteins where diseases try to invade:

The Red Queen hypothesis for sex is simple: Sex is needed to fight disease. Diseases specialize in breaking into cells, either to eat them, as fungi and bacteria do, or, like viruses, to subvert their genetic machinery for the purpose of making new viruses. To do that they use protein molecules that bind to other molecules on cell surfaces. The arms races between parasites and their hosts are all about these binding proteins. Parasites invent new keys; hosts change the locks. For if one lock is common in one generation, the key that fits it will spread like wildfire. So you can be sure that it is the very lock not to have a few generations later.

Evidence in a species of New Zealand lake snail shows that those that produced sexually were much less likely to be infected by a common parasite than those that were the product of asexual production. But in subsequent generations that pattern flips, which may mean that for organisms that go both ways, reproductively, the ability to switch itself conveys a benefit.

Looking for evidence explaining why sex persevered is even more complicated. We may someday know why sex started in the first place, but figuring out why asexual reproduction was never resurrected in the animal kingdom is trickier.

Sex allows species to adapt to the loss of food sources, the arrival of parasites, rising temperatures, and more. There is some doubt, however, whether the environment fluctuates fast enough to warrant the prevalence and persistence of sex in the eukaryotic kingdom. “Is the force favoring sex large enough in the face of the costs?” asks theoretical biologist Sally Otto. “The niggling doubt in the back of my head is that it is not.”

Read More »

Read More »

Read More »

When it comes to getting creative in the bedroom, we humans may think we’re the experts. In fact, we’ve barely scratched the surface of how varied and multifaceted reproduction can be—just look at species that do the deed through kinky-sounding strategies like sperm sequestration, “virgin births” via cloning or even hybridizing with other species. These may sound like show plots of a new series on the Space Channel, but they’re actually just some of the many tricks that Mother Nature uses to stay a few steps ahead of Cosmopolitan Magazine’s sex tips.

Moreover, some of these unconventional methods are making scientists rethink the basic tenets of reproductive biology, says Ingo Schlupp, a professor of biology at the University of Oklahoma. His study subject, the asexual Amazon molly fish, defies the so-called rules of reproduction by making perfect clones of itself, sans males. With such a lack of genetic diversity, these finger-sized fish should have been wiped out by disease long ago, Schlupp points out.

“How on earth do these guys survive for such a long time without any recombination?” he says. “To me that’s a real head scratcher. Here’s a species that doesn’t [recombine their genes every generation] and theoretically should have been dead many thousands of generations ago, but yet they’re living happily.”

We still haven’t unraveled all the mysteries. But one thing’s for certain: The more we learn about “alternative “reproduction strategies across species, the more we realize that many of them might not be so alternative after all. Now that they know what to look for, biologists are finding more and more cases of strange and hitherto unknown forms of animal procreation. In other words, baby-making outside the “traditional” male-female pairing could be far more widespread than we humans are inclined to think.

Roughly 100,000 years ago, in a romantic lagoon near Tampico on Gulf side of Mexico, two distinct fish species—a sailfin molly male and an Atlantic molly female—came together in an unlikely union. The colorful pair gave birth to the Amazon molly: an all-female, asexually reproducing mini-carrot length fish named after the all-female tribes of Greek legend, according to Schlupp of the University of Oklahoma.

Yet while these Amazons need no male genetic material to reproduce, they’re not entirely independent. To kickstart their reproductive systems, they still need sperm. In a bid to find a suitor into this kind of thing, Amazons will actually disrupt mating processes between sexually reproducing mollies they come across in an effort to steal the male’s seed from his erstwhile mate—by literally squeezing in between the pair.

“They kind of butt in and then it’s almost as if they’re hoping to get the mating that was meant for another female,” Schlupp says. “The males that these Amazon mollies are mating with really have to get up close and personal with the Amazon mollies. These fishes have a specialized fin that they use to transfer sperm—we’re actually talking about real copulation. It’s not like a mass spawning where some parasitic female swoops in and gathers some sperm.”

Read More »

You must have seen the famous squishies by now. They are everywhere. In stores, on Instagram, at your friends’ house – they’ve become omnipresent.

But, you may be wondering what precisely they are. Worry not, you’re not alone. Simply put, they are squishies. You may think this doesn’t explain anything, but it does. You squish them, hence the name.

What are squishies?

These soft toys are made from polyurethane foam. When you first take them in your hand, they’ll have a similar feel to a stress ball. But, they are so much more. Like a stress ball, you can squeeze them as much as you like and they’ll always revert to their original form. However, unlike the stress ball, they come in many fun shapes and sizes.

You can get animal squishies, food squishies or a squishy that looks like your favorite cartoon character. The possibilities are endless! And, we mean that. You can even get a combination squishy, like a mix between your favorite food and animal. It might sound weird, but it’s adorable, believe us!

Looks so pretty and smells even better

If the fun size and the bright colors aren’t enough for you, you can get a scented squishy, as well. Most of the scents are food-related, so your banana squishy can smell like a banana, too. Imagine squeezing your cookie squishy and smelling that freshly-baked scent all day. Sounds nice, right?

Size is everything

Just because they’re usually small, it doesn’t mean you have to limit yourself to a tiny squishy. You can also get jumbo-sized squishies for your bed or desk. Or, you can go even smaller and get a tiny one for your keychain.

Who thought of this?

The Japanese, of course. These squishies are the epitome of Kawaii, a word that means “cute”or “adorable” in Japanese. In fact, squishies were born in the capital of cuteness – the Harajuku district of Tokyo. They were created over thirty years ago as a toy appealing to all ages. They have been a beloved pastime in Japan ever since. However, their popularity outside of Japan started skyrocketing just recently.

The first squishies were in the form of famous Japanese characters, like Hello Kitty and  Rilakkuma. However, soon the trend started to spread like wildfire, and squishies soon took the shape of favorite snacks, beverages, animals, etc.

The soft design and delicate texture made them instantly popular among both young and adult kawaii culture lovers. They come in all sizes, so they can be used as accessories for bags and briefcases, phones, keychains and so much more.

Why are they such a trend?

Squishies are perfect accessories, bringing that much-needed touch of cuteness to your outfit. They also help people express their interests and hobbies. Furthermore, they are great collectibles.

Squishies are a real dream for collectors of cute pop culture paraphernalia. You can collect them and swap them with friends, or show off your collection to other enthusiasts.

However, that’s not all. Squishies are also great stress relievers. They function like a stress ball. You can use them to get rid of excess energy and focus on one task while your stress levels go down. They’ll never lose shape, no matter how many times you squeeze them. They are soft and have a pleasant texture, so you’ll enjoy playing with them.

A soft, brightly-colored stress relief? What more could you ask for, really? Carry them in your bag, on your keychain or phone for instant access to the most adorable stress relief ever.

Read More »