The world's unsolved problems
993 open questions across 14 fields, gathered from Wikipedia. Pick one and start thinking.
Showing all 993 problems · surprise me
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Snowball Earth
what was the effect of Cryogenian glaciations on the origin and evolution of early animals?
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Eocyathispongia
is it an early sponge? Did it have choanocytes?
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Vernanimalcula guizhouena
is this fossil organism an early bilaterian?
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Tullimonstrum
a taxonomic position of this fossil organism is unknown.
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Adult form of Planctosphaera pelagica, a hemichordate known, as of 2023, only by its tornaria larvae. Due to differences between larvae of…
Adult form of Planctosphaera pelagica, a hemichordate known, as of 2023, only by its tornaria larvae. Due to differences between larvae of acorn worms and that of Planctosphaera pelagica, Planctosphaera is sometimes given its own class.
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Xenacoelomorpha
are they deuterostomes, forming a clade Xenambulacraria together with echinoderms and hemichordates, or rather primitive bilaterians and a sister group to Nephrozoa?
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Jennaria pulchra
the taxonomic position of this animal is unknown and more research is needed to establish it.
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Nervous system of Lobatocerebrida. Why do these simple unsegmented annelids, which are unselective deposit feeders and lack sense organs,…
Nervous system of Lobatocerebrida. Why do these simple unsegmented annelids, which are unselective deposit feeders and lack sense organs, have a relatively complex brain?
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Diurodrilus
is it an unusual annelid? What are the origins of morphological similarities between Diurodrilus and micrognathozoan Limnognathia maerski?
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Taxonomic position of pentastomids. Are they a sister group to Argulidae or an ancient lineage of Panarthropoda?
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Taxonomic position of Tricholepidion gertschi
is it a member of the order Zygentoma (silverfishes) or an independent ancient lineage of insects?
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How will organisms respond to complex, novel environments? Climate change is of significant relevance.
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What is the relative importance of variability, across scales, and its mechanisms?
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Why does intragenotypic variability persist? Striking phenotypic differences exist even among individuals with identical genotypes, and…
Why does intragenotypic variability persist? Striking phenotypic differences exist even among individuals with identical genotypes, and environments.
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What determines population density? There is disagreement over which regulatory mechanisms of population are density-dependent, or…
What determines population density? There is disagreement over which regulatory mechanisms of population are density-dependent, or density-independent.
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Why are all leaves the size they are, and not an order of magnitude larger or smaller? How is the upper limit on leaf size set?
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Persistence paradox
why does the evolution of novel species almost never lead to the extinction of resident species?
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Is the ecosystem a superorganism, or a collection of organisms? Could the Earth be a superorganism, or a unit of selection?
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Why do Pogonomyrmex badius colonies cover the surface of their nests with a circular region of charcoal pieces?
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Homing. A satisfactory explanation for the neurobiological mechanisms that allow homing in animals has yet to be found.
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Flocking (behavior). How flocks of birds and bats coordinate their movements so quickly is not fully understood. Nor is the purpose of…
Flocking (behavior). How flocks of birds and bats coordinate their movements so quickly is not fully understood. Nor is the purpose of large flocks like those of starlings which seem to invite predators rather than protect them.
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Butterfly migration. How do the descendants of monarch butterfly all over Canada and the US eventually, after migrating for several…
Butterfly migration. How do the descendants of monarch butterfly all over Canada and the US eventually, after migrating for several generations, manage to return to a few relatively small overwintering spots?
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Blue whale. There is not much data on the sexuality of the blue whale.
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Gall-inducing insects. At least seven groups of insects, in six orders, have independently evolved the gall-inducing habit. Several…
Gall-inducing insects. At least seven groups of insects, in six orders, have independently evolved the gall-inducing habit. Several adaptation hypotheses have been proposed, but it is largely unknown why this habit evolved and how gall-inducing insects...
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Korarchaeota (archaea). The metabolic processes of this phylum of archaea are so far unclear.
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Glycogen body. The function of this structure in the spinal cord of birds is not known.
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Arthropod head problem. A long-standing zoological dispute concerning the segmental composition of the heads of the various arthropod…
Arthropod head problem. A long-standing zoological dispute concerning the segmental composition of the heads of the various arthropod groups, and how they are evolutionarily related to each other.
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Ovaries of basking sharks. Only the right ovary in female basking sharks appears to function. The reason is unknown.
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Brightly colored bird eggs. It is unknown what evolutionary process would lead birds to having brightly colored eggs given the increased…
Brightly colored bird eggs. It is unknown what evolutionary process would lead birds to having brightly colored eggs given the increased visibility to predators.
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Stegosaur osteoderms/scutes. There is a long-standing debate over whether the primary function of the osteoderms/scutes of stegosaurs is…
Stegosaur osteoderms/scutes. There is a long-standing debate over whether the primary function of the osteoderms/scutes of stegosaurs is protection from predators, sexual display, species recognition, thermoregulation, or other functions.
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Data last refreshed 2026-10-20 03:01 UTC.