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Unfortunately an incomplete answer, hopefully others can add to this or fill out the details missing. After a bit of searching, I found the original reference: Plecoptera was named by Burmeister in 1939. I believe that this was a split of a previous clade, probably the Megaloptera. The book is available on Google books in the following link: Burmeister 1939 ...


1

This is a "sand hopper" (Talitridae), also known as "land hoppers" or "sand fleas". The Talitridae are a cosmopolitan family of arthropods, known for their hopping behaviour when disturbed. Which of the genera it is from would be impossible to determine without detailed close-up pictures and a bit of expert knowledge which is ...


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Advantages of air breathing over gills? Keeping in mind water-breathing animals could still evolve lungs. Not being vulnerable to parasites and diseases of the gills, which are obliged to have blood supply close to the water. Able to colonise water regardless of salinity, able to survive warm water.


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Thermoregulation and echolocation both depend on evolutions that occurred on land and seem to be less accessible to fish than to the ancestors of mammals. The heat capacity of water is much greater than air, so maintaining an elevated temperature in body tissues is both more difficult and less necessary. Still, some fish lineages have independently evolved ...


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Sea cucumber. There are over 1700 known species, all inhabiting the sea-bed, mostly in deep waters, but can be found on the continental shelf in many areas. An echinoderm (alongside sea-urchins and starfish), belonging to the family Holothuroidea, they distinguish themselves from sea urchins by "lying on their sides". They're radially symmetrical ...


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Membership of nominal species is certainly an equivalence relation. For instance, membership of Canis familiaris, or domestic dog. Dogs are not wolves, and wolves are not dogs. But all domestic dogs are the same species. But of course, some taxonomists recognize the dog as a subspecies of the wolf, as in Canis lupus familiaris. In that case, dogs and wolves ...


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