As we develop tools to explore other worlds for signs of life, there’s still so much we don’t know about life right here on Earth. The mysteries of the living world are as diverse and fascinating as all the various organisms that call this planet home, including our own species. They also raise some fundamental questions about the frontiers of our knowledge, as even after extensively studying and documenting creatures all over the world for so long, we’re still no closer to solving them.
10. Why Did the Ancestors of Whales Go Back Into the Water?
Let’s think about whales (or, at least, their evolutionary ancestors) for a second. These are creatures that started out in the water, spent time on land going through all the stages of evolution right up to the mammal stage, decided that it wasn’t worth it and went back into the water. If you were an evolutionary scientist, this path of evolution would totally baffle you, as there’s no seemingly good reason to do that.
Whales are, in fact, one of the biggest mysteries in evolutionary biology. We still don’t understand why they made the move back into water at all, as early whales would have been bad swimmers and ill-adapted to a life entirely inside water.
Some scientists think that it was one of the many after-effects of the extinction event that killed the dinosaurs, as it also killed off many large marine reptiles – including many fearsome crocodilian species. According to this theory, at least, whales moved back into the water to capitalize on that gap.
9. Why Did We Leave Africa?
All people on Earth today are direct descendants of a single, small group of homo sapiens that first left Africa around 50,000-60,000 years ago. While we know that it definitely happened from archaeological and genetic evidence, we’re still not entirely clear on the ‘why’. What exactly made our ancestors leave the relatively mild climate of Africa – where they had been living for more than a 100,000 years by that time – for potentially inhospitable, unknown lands to the north?
Scientists still don’t have a satisfactory answer to that, though they do have a few guesses. One likely culprit is climate change and an ice age that happened across North Africa around that time, forcing our earliest ancestors to start looking for greener pastures. This doesn’t seem likely, however, as studies from Ethiopia suggest that the climate around the time of the exodus would have been mild and favorable for humans. Another theory says that we may not have left towards the north at all, and the migration might have instead started much earlier from Africa’s southern coasts.
8. Mystery Life Forms Under Antarctica
If you look at the topographical map of Antarctica, you’d see that the continent extends far beyond its landmass, in the form of a permanent, floating ice sheet. Under that sheet lies a world that has never even been seen before, let alone properly explored for signs of life. It’s one of the most extreme, inhospitable environments we know of, as well as one of the most inaccessible, making its exploration expensive and hard to undertake.
It’s also home to a mysterious type of life form we only recently came to know about, thanks to one study published in Frontiers in Marine Science. Living in an environment fully devoid of any type of nutrients and about 260 miles away from the nearest source of light, these sponge-like creatures are unlike anything we’ve seen or documented before.
Unlike jellyfish and other unlikely visitors that have been spotted in these parts before, they’re stuck to the seafloor and can’t move to get essential nutrients elsewhere, making their existence even more baffling for the researchers. It may be an entirely new type of life that doesn’t need to feed for years – perhaps decades – to survive, even if we’re still not sure they eat anything at all.
7. Why Do We Love Music?
Even if a lot of us would disagree, our taste in music is more objective than we think. Of course, the kind of music we like depends on vastly subjective factors like culture, language and time period, though everyone still has the same concept of what makes a beat – in a manner of speaking – slap.
Evolutionarily speaking, however, our love for music is a mysterious trait we don’t fully understand. At least as far as we can tell, music – or the way we enjoy music – is unique to humans. It must have served a purpose during our evolution, as the trait has been successfully passed down through the generations, though it’s unclear what that might have been.
Some studies do prove that when we listen to music we enjoy, our brain releases ‘feel-good’ chemicals like dopamine to elevate our mood. That still doesn’t explain why it happens at all, though, as that’s not essential – or even required – for survival.
Scientifically, we know that music is merely waves arranged in a special, repeating manner that we seem to enjoy. That suggests that it may have something to do with the way our brain recognizes and appreciates patterns in nature, which must have been crucial for survival in our early days.
Breasts occupy a space in modern human culture that goes beyond their anatomical – or even sexual – utility. We can see their influence all around us, from advertisements to movies to art. They make perfect evolutionary sense, too, as breasts serve the crucial function of feeding and nurturing a newborn.
What’s baffling, though, is how human breasts are sort of always there. It’s actually one of biology’s biggest mysteries, as this is unique to humans. While all mammals possess breasts, they only show up when needed for feeding.
One theory says that permanently enlarged breasts evolved as a sexual trait, as more attractive boobs help attract better mates. That sounds obviously true, but there’s also the fact that they cause a lot of problems for women. Breasts are more likely to develop cancer than any other organ in a woman’s body, along with other issues like chronic back ache, making it a rather costly trade-off.
5. The Female Orgasm
Most of us see the female orgasm as just the female version of the male orgasm, though anatomically, they couldn’t be more different. The male orgasm serves a definite, clear purpose in the process of reproduction, as it allows for the dissemination of… well, you know how it works.
The female orgasm, on the other hand, seems to serve no purpose at all. It’s not required for reproduction, as women have a totally different mechanism for releasing their eggs. The female orgasm isn’t necessary to the sexual experience, either, as it’s completely possible to conceive without it. That’s likely why women orgasm only about 30-40% of the time – according to one study, at least – and about 22% of them have never experienced it during intercourse.
The female orgasm serves no clear evolutionary purpose, and many biologists believe that it’s just a vestige of the male orgasm, similar to male nipples. However, that doesn’t explain why the clitoris – the primary organ responsible for the female orgasm – is so developed. It must have served a purpose in the past, which is why it hasn’t disappeared over the course of our evolution, though what that was is anyone’s guess.
Memory isn’t a uniquely human feature; many studies have confirmed that it exists in nature in various ways. Just take migratory animals as one example: all of them know their routes perfectly, even when they’re making the journey for the first time. Memory exists in various forms in many major branches of life, even though we still don’t quite understand all of them.
The bigger mystery, however, is the fundamental mystery of how all of us developed the trait in the first place. Memory is encoded in the brain with a special substance called Arc, which prepares neurons to be used in the storing and retrieval of memories. It’s present in all animals with the ability to remember, though we still don’t know much about it on the cellular or molecular level.
We don’t know its evolutionary origins, either, though, curiously, the structure of Arc almost perfectly mimics some retroviruses – a family of viruses that includes HIV. While it’s all in the realm of speculation, that does suggest that memory may be an accidental by-product of an ancient viral disease.
The mystery of anesthesia ties into the large mystery of consciousness itself, which lies more in the realm of philosophy than biology. Strictly anatomically speaking, however, anesthesia and how it works in the body is one of the biggest problems in medicine, even if we rely on it for almost all of our surgical procedures.
Even after decades of research and studies on the topic, we’re no closer to understanding exactly what anesthesia does in the brain to completely switch off our consciousness. If we can figure it out, it’d get us one step closer to decoding the biological basis for consciousness, with far-reaching consequences for both medicine and philosophy.
The mystery of anesthesia and how it interacts with our brain is why anesthesiologists are easily the highest paid medical professionals out there, as administering the right dose of it and reliably inducing unconsciousness is a highly prized skill in the medical field.
2. The Microbes Inside Us
We’ve known about the presence of microbes that live inside our body for a while, though it’s unclear what all of them really do. Most of them could be found somewhere in the gastrointestinal system, engaged in a symbiotic relationship that benefits both. Or at least that’s what we’re guessing, as we have no idea how most of them benefit us.
The fact that they’ve consistently been selected for throughout our evolution suggests that these microbes must have played a crucial role during our evolution. Even today, gut bacteria is widely believed by doctors and other medical experts to be good for the body, even if many of these organisms are still completely unknown to science. As for the numbers, according to one study from 2018, the microbes to human ratio inside our body may be as high as 1.3 to 1.
1. The Intelligence Explosion
Whenever we think of giant leaps in the history of human civilization, we think of periods like the Neolithic revolution about 10-13 thousand years ago – when we first organized ourselves into agricultural societies – or even the more recent Industrial or digital revolutions. Our biggest leap, however, came about 80,000 years ago, when homo sapiens was still a primitive humanoid species competing for land and food with other humans and predators.
We lived like that for more than 200,000 years, with little to show for it in terms of technological or societal progress. Then, about 80,000 years ago, something happened that changed our basic, stone-based tools into complicated ones made with bones and other materials. It wasn’t just the tools – fossils show a marked, exponential improvement in many fields over the course of the next 20 millennia or so, including art, architecture, political arrangement and rituals.
It happened so long ago that we have no idea what triggered it, though some experts think that the Mount Toba explosion event in Sumatra about 74,000 years ago may have been one of the factors. As the Earth cooled and went through the after effects of one of the largest volcanic explosions in its history, evolutionary pressures might have forced homo sapiens to think harder to survive.