Did you know that there are mysteries of evolution we have yet to solve? A lot is already known about the origins of humans and how life in general has evolved here on Earth. But in spite of our current knowledge, there are things that are still baffling scientists. From missing links in animal evolution to mysterious ancestors of modern humans, check out these 25 unsolved mysteries of evolution.
While most species have evolved significantly over the ages, there are some that have remained practically unchanged for millions of years. Known as living fossils, these creatures are priceless for scientists as they provide rare glimpses at how life on Earth might have looked like in the prehistoric era. One such creature is the Coelacanths. This fish was thought to have gone extinct 70 million years ago until a recently dead specimen was found in South Africa in 1938. If animals have evolved throughout the years, why do living fossils fail to evolve or evolve slower? Scientists have a few theories that include genes with a lower rate of “substitution” and living environments that fail to promote a need for evolution.
The first hominim species, a line of primates that eventually led to the origin of humans, was long believed to come from Africa. However, recent studies of two fossils of the species Graecopithecus Freybergi, which were discovered in Greece and Bulgaria, suggest it actually might have been here where the first ancestors of modern humans emerged some 7.2 million years ago.
Origin of Bipedalism
There have been many theories on why and how our hominid ancestors became bipedal. Some theories argue it was because the primates needed to have their hands free to use tools and carry food while others claim it was because they had to look over tall grass etc. The best clues to our upright origins may come from living apes but no one knows for sure how much chimpanzees have evolved from the last common ancestor they shared with us.
Evolutionary Reversal: Whales
The evolution of whales has always been a mystery. For a long time, scientists had no idea how these giant, big-brained, air-breathing and warm-blooded mammals got into the sea. Now we know that it happened during a very unusual back-to-the water evolution as modern whales evolved from prehistoric terrestrial mammals. However, scientists have yet to discover why this bizarre evolutionary reversal occurred.
Origin of Language
There is an ongoing debate over how and when human language started. Some scientists think that our human ancestors started talking as soon as their brains became large and sophisticated enough while others suggest that language evolved slowly, from gestures and sounds used by our earlier ape-like ancestors.
When and why our ancestors lost fur is another mind-boggling question that evolutionary scientists have been trying to answer. It might have happened due to the change of environment the hominids lived in or simply to reduce the prevalence of external parasites that routinely infested their fur.
Cicadas´ Life Cycle
Cicadas are known to lead one of the most mysterious lives in the entire animal kingdom. Some species of this insect can be hidden under the ground for up to 17 years before surfacing to mate. What makes evolutionary biologists even more confused is the fact that some cicada species somehow synchronize their mating cycles with other species.
Big Brains in Humans
Scientists have discovered that as “recently” as 2 million years ago, our ancestors had brains about the size of modern chimps. Then, however, hominid brains began to grow significantly and they continued to balloon until they neared their present size at about 160,000 years ago. Scientists agree that large brains must have given hominids a great evolutionary advantage but it is not known what actually caused the enormous development of their brains.
First Use of Tools
There’s been a long argument over the timing of the first use of tools. For decades, the earliest known stone tools were associated with their presumed maker, an ancestor less than two million years old called Homo Habilis (or “Handy Man”) but recent studies suggest our ancestors might have first used crude tools more than half a million years earlier.
One of the most famous missing links in evolution of vertebrates, Eucritta was a bizarre, small creature that lived in modern Scotland some 350 million years ago. The animal possessed a weird blend of tetrapod-like, amphibian-like and reptile-like characteristics but no one has yet identified what the direct successor of Eucritta was. Some experts suggest it might have been one of the first true amphibians.
The Evolution Of Human Female Orgasm
This may seem a bit odd, but the question of “why do women have orgasms?” has confused scientists for quite sometime. Orgasms are not necessary for conception and women can experience an orgasm even when they are not engaged in reproductive sex. Though the answer to this question has eluded scientists, there are a few theories out there. One of these theories suggest orgasms are merely vestige leftovers of evolution. Another theory suggests that orgasms are tied to ovulation and not reproduction.
The key part of the origin of life on Earth, abiogenesis is the natural process by which life arises from non-living matter. Despite decades of extensive research and collaboration among different scientific fields such as geophysics, chemistry, biology etc. scientists still rack their brains over this most existential question – how the transformation of the non-living into the living actually happened.
Humpback Whale´s Songs
The Humpback whales are known for their mysterious songs but the reason behind this evolution still escapes scientists. In 2015, a completely new, haunting sound was recorded in the Humpback whales near the Hawaiian Island of Maui. The mysterious new song had such a low beat it was barely audible to human ears. The sound has been described: “as if listening to a heartbeat with a stethoscope”.
Labeled as the “Anti-Missing Link”, Australopithecus Sediba have left scientists with many questions. Discovered in 2008 in Malapa, South Africa; the fossil skeletons of Au. sediba are remarkably complete. Scientists have been able to highlight the presence of primitive and derived traits which show part of the transition to bipedal walking. However, the legs and feet show a previously unknown form of walking upright. The combination of primitive traits found in other australopithecines and derived traits found in the genus homo makes it difficult to place Au.sediba in an evolutionary position.
Discovered in 1861, shortly after Darwin published his revolutionary work “On the Origin of Species”, Archaeopteryx was long considered the first bird to have ever lived on Earth. Yet, modern researches suggest this iconic feathered creature (which lived 150 million years ago) was more of a dinosaur than a bird, which would push the appearance of birds forward to a more recent past. Some experts even argue Archaeopteryx might have represented an evolutionary dead end.
Some animals, such as tortoises, are known to live remarkably long lives. A giant tortoise named Jonathan is currently the world´s oldest living terrestrial animal at an incredible age of 184 years. While scientists have noted that longevity is usually associated with slow metabolism, there is still controversy as to why. Moreover, slow metabolism cannot be the only reason why some species live significantly longer than others.
End of Human Evolution
There is an ongoing debate on whether humans are still evolving or not. Some experts, including famous British naturalist David Attenborough, believe that humans have already stopped evolving, at least in physical terms, as we are now able to keep even the weakest individuals of our species alive. According to this theory, we are not longer subject to the Darwinian natural selection. But other scientists argue that human evolution still continues so it seems that only time will answer this question.
Evolution of Snakes
How and why snakes lost their legs during the evolution has always been a mystery. It was long thought that snakes gradually lost their limbs in order to live in the sea but recent CT scan research of prehistoric snake fossils suggests it actually might have happened when ancestors of modern snakes adapted to life in burrows.
Legends of human-like creatures such as Bigfoot or Yeti have fascinated us for centuries and evolutionary experts admit there is a slim chance that unknown hominin species might exist in some remote regions. In fact, various hominin species coexisted alongside our ancestors for most of human history and our family tree can still surprise us even today. Just a few years ago, for example, skeleton of hominin species Homo Floresiensis (also known as the hobbit) was discovered in Indonesia.
Human ancestors achieved several impressive migrations over the past thousands and millions years. Homo Erectus made the first great trek out of Africa and into east Asia as early as 1.8 million years ago. Around a million years later, the predecessors of Neanderthals turned up in Europe and 125,000 years ago, Homo Sapiens made an early foray into the Middle East. Overpopulation and climate changes are some of the most common explanations as to why they did it but we might never know that for sure.
Also known as the virgin birth, parthenogenesis is a natural form of asexual reproduction that has been observed in some plants, invertebrates and a few vertebrates. Scientists thought the purpose of this rare evolutionary feature was to ensure a bloodline goes forward in the absence of suitable fathers but parthenogenesis has been recently documented in snake females even thought they were healthy males available for them.
A symbol of conservational efforts and one of the most popular bear species in the world, the giant panda has been baffling evolutionary scientists for years. These cute bears have been ridiculed for their decidedly non-bearlike vegetarian diets, apparent lack of interest in sex and tendency to spend the majority of their time just sitting, eating and defecating (about 40 times per day). How this animal, so poorly suited for survival, has made it through tens of thousands of years of evolution, remains unclear.
Scientists were surprised to discover that more and more African elephants are born without tusks. The cause of this bizarre phenomenon is believed to be massive poaching of tusked elephants that has been ravaging wild populations of African elephants. Not having tusks might protect the animals from poaching but it is unclear how the new generations of tuskless elephants will adapt to life as the giant mammals use their tusks to dig for food and water, for self-defense, sexual display etc.
The scientific community was shocked when a finger bone fragment found in 2010 uncovered the existence of a group of ancient humans no one had seen before – the Denisovans. Since then, just a few more little fragments of this species´ bones have been found, which is why this mysterious hominin remains largely unknown to us. What we do know though is the fact that the Denisovans must have mated with (anatomically) modern humans as the Denisovan DNA has been found in some modern living people, mostly from Papua New Guinea, Australia and Oceania.
The Denisovan is not the only hominin species that has been boggling minds of evolutionary experts all over the world. In 2013, skeletons of another mysterious hominin family were found in a South African cave. Even after an extensive research, scientists were not sure where the newly discovered species (now known as Homo Naledi) fits in the scheme of human evolution as the fossils displayed a bizarre combination of characteristics found in several different species including Australopithecines, early Homo Habilis, Neanderthals and even modern humans.
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