This "Cambrian explosion" included the evolution of arthropods (ancestors of today's insects and crustaceans) and chordates (animals with rudimentary spinal cords). In the Paleozoic Era, life flourished in the seas. After the Cambrian Period came the 45-million-year Ordovician Period, which is ...
Only one family dominates the top predator role, thegorgonopsians, making up nearly all the specimens known (C inFig. 2). Large gorgonopsids were present but very rare in the precedingTapinocephalusZone (Dinocephalianempire). The medium-size hipposaurids, also present in theTapinocephalusZone...
Giant InsectsIt is this high oxygen content that is believed to be the cause of the gigantic arthropods that lived in these forests. A dragonfly called Meganeura had a wingspan 70 cm! The centipede like Arthropleura could reach a length of 1.8 meters and giant scorpions grew over 50 cm ...
PENNSYLVANIAN TIME-SCALE PROBLEMS- the usual given for the Pennsylvanian is around 34 million years. A meticulous new study of central Europeanstratigraphynow pegs the Pennsylvanian as spanning only 19 million years; a 44% change! This figure, if it is genuine, casts doubt on the origin of the...
Insects are a group in which feeding on plants increases rates of species proliferation, including among the butterflies and moths, which are almost all herbivorous. Credit: Daniel Stolte/UANews The scientists then mapped the vast dataset ofanimal speciesand their dietary preferences onto anevolutionar...
on moist environments for reproduction: waterborne spores were replaced by seeds in plants of seed-fern origin, and shell-less eggs were replaced byamnioteeggs with protective shells in animals of reptilian origin. Flight was first achieved also during the Carboniferous Period as insects evolved ...