What can't evolutionary biology explain?

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Main topic: Science
Short answer:
  • Origin of bipedalism, language, and naked human
  • Reverse evolution in whales
  • The big-foot humans and the big-brain humans
  • Mystery of Archaeopteryx, Eucritta, and Cicadas´ life cycle
  • Coelacanth living fossils
  • Origin of Denisovan, Homo naledi, and the first hominim

The research on evolution is ongoing, and sometimes the discovery of answers results in further questions. Much information has already been gathered regarding humanity's history and life development on Earth. However, despite their best efforts, scientists cannot solve some mysteries, from the undiscovered linkages in animal evolution to the unknown forebears of contemporary humans.

The major mysteries that are yet to be explained by evolutionary biology are:

The origin of bipedalism, language, and loss of fur on humans remain unanswered, and research is ongoing[edit]

Many ideas explain how our hominid ancestors became bipedal. Some say primates required their hands to use tools and carry food independently, while others say they had to look over the tall grass.

Living apes may hold the key to our upright origins, but no one knows how much chimpanzees have evolved from our last common ancestor.[1]

There are disputes over the origins of language. Some scientists believe our ancestors started talking as soon as their brains were huge and complex, while others believe language emerged slowly from ape-like gestures and sounds.[2]

Another intriguing subject for evolutionary scientists is when and why our ancestors lost fur. It may have happened because of the hominids' changing environment, to regulate body temperature, or to eliminate external parasites that contaminated their fur.[3]

Reverse evolution observed in whales is a mystery that is still baffling scientists[edit]

Whales' history has always been challenging to figure out. Scientists didn't know how these giant, warm-blooded, air-breathing mammals got into the water for a long time.

Now it's known that it happened during a strange back-to-the-water evolution when prehistoric land mammals turned into whales. Scientists have yet to figure out why this peculiar change in evolution occurred.[4]

The mystery of the evolution of the bigger brain in humans is yet to be uncovered[edit]

Scientists found that our ancestors had chimp-sized brains 2 million years ago. However, hominid brains began to expand and reached their current size about 160,000 years ago.

Scientists believe hominids' large brains gave them an evolutionary advantage, but they don't know why this evolutionary path occurred.[5]

The mystery of archaeopteryx, eucritta, and cicadas' life Cycle and evolutionary advantages is under research without any concrete answers[edit]

Archaeopteryx, discovered in 1861, was long considered the first bird on Earth. The modern study suggests this iconic feathered creature (which lived 150 million years ago) was more of a dinosaur than a bird, pushing the appearance of birds forward to a more recent past. Some researchers believe Archaeopteryx was an evolutionary dead end.

Eucritta, a weird, little species that existed 350 million years ago in contemporary Scotland, is one of the most renowned missing vertebrate links. No one knows what Eucritta's direct descendant was, but it had tetrapod, amphibian, and reptilian traits. Some researchers think it was one of the first amphibians.[6]

Cicadas live mysteriously. This beetle can stay underground for 17 years before mating. Some cicada species synchronize their mating cycles with others, which confuses evolutionary biologists even more.[7]

Emerging cicada
Emerging cicada. Image Credit: Martin Nielsen, M.Nielsen Photo, CC BY-SA 4.0, via Wikimedia Commons

The living fossil Coelacanth's slow evolution has no explanation yet[edit]

Even though most species have changed a lot over time, a few haven't changed much in millions of years. Scientists love these creatures, called "living fossils" because they give them rare glimpses into what life on Earth might have been like in the past.

Coelacanths are one of these animals. People thought this fish had been extinct 70 million years ago, but in 1938, scientists discovered a dead Coelacanth in South Africa.

Coelacanth Fish. Image Credit: Nkansah Rexford, CC BY-SA 3.0 via Wikimedia Commons

Some scientists hypothesized that their evolution is slow because genes don't "substitute" as often, and the unchanged living environments probably make evolution unnecessary.[8]

The origins of various extinct hominid (human-like) species like Denisovan, Homo naledi, and first hominin remain a mystery[edit]

The scientific community was shocked when a finger bone fragment found in 2010 uncovered a group of ancient humans no one had seen before – the Denisovans. Since then, just a few more pieces of this species' bones have been found, which is why this mysterious hominin remains largely unknown.

Scientists discovered that the Denisovans must have mated with (anatomically) modern humans, as the Denisovan DNA has been found in some contemporary living people, mainly from Papua New Guinea, Australia, and Oceania.

The Denisovan is not the only hominin species that has been boggling the minds of evolutionary experts worldwide. In 2013, scientists discovered skeletons of another mysterious hominin family in a South African cave. Even after extensive research, scientists were not sure where the newly discovered species fit in the scheme of human evolution. The fossils displayed a bizarre combination of characteristics in several species, including Australopithecines, early Homo Habilis, Neanderthals, and even modern humans.

The first hominin species, a line of primates that eventually led to the origin of humans, was long believed to have come from Africa. However, recent studies of two fossils of the Graecopithecus Freybergi discovered in Greece and Bulgaria suggest it might have been here where the first ancestors of modern humans emerged some 7.2 million years ago.[1]

Fossils of Graecopithecus Freybergi. Image Credit: Jochen Fuss, Nikolai Spassov, David R. Begun, Madelaine Böhme, CC BY 4.0, via Wikimedia Commons


  1. Gruss, Laura Tobias; Schmitt, Daniel (2015-03-05). "The evolution of the human pelvis: changing adaptations to bipedalism, obstetrics and thermoregulation". Philosophical Transactions of the Royal Society B: Biological Sciences. 370 (1663): 20140063. doi:10.1098/rstb.2014.0063. PMC 4305164. PMID 25602067.CS1 maint: PMC format (link)
  2. Hauser, Marc D.; Yang, Charles; Berwick, Robert C.; Tattersall, Ian; Ryan, Michael J.; Watumull, Jeffrey; Chomsky, Noam; Lewontin, Richard C. (2014). "The mystery of language evolution". Frontiers in Psychology. 5. doi:10.3389/fpsyg.2014.00401/full. ISSN 1664-1078.
  3. "What is the latest theory of why humans lost their body hair? Why are we the only hairless primate?". Scientific American. Retrieved 2022-11-07.
  4. "Weird and Wacky, the Strange Evolution of Whales". www.misfitsandmysteries.com. Retrieved 2022-11-07.
  5. "Why do humans have such huge brains? Scientists have a few hypotheses. - Vox". www.vox.com. Retrieved 2022-11-07.
  6. Leigh, Egbert Giles (2014-12). "Alan Feduccia's Riddle of the Feathered Dragons: what reptiles gave rise to birds?". Evolution: Education and Outreach. 7 (1): 1–3. doi:10.1186/s12052-014-0009-0. ISSN 1936-6434. Check date values in: |date= (help)
  7. "Life cycles are long, mysterious for cicadas | Mississippi State University Extension Service". extension.msstate.edu. Retrieved 2022-11-07.
  8. "Weird 'living fossil' fish lives 100 years, pregnant for five". India Today. Retrieved 2022-11-07.