Month: September 2022

ANCIENT BODY PATTERNS. “The basic animal body plans are half a billion years old. Arthropods, chordates, mollusks, echinoderms and others can all be recognized from the first appearance of the animal fossil record. Even so, the striking diversity of living animals shows that dramatic evolutionary transformations have taken place within these ancient patterns." https://lnkd.in/d2_xbfe View in LinkedIn

CONSERVED BODY PLANS. "Higher taxonomic groups, most notably phyla, poses suites of anatomical features that distinguish them from other groups. Such an underlying anatomical arrangement is called a body plan. Body plans arose rapidly during the radiation of the first animals but have been conserved since their first debut." https://lnkd.in/d2_xbfe View in LinkedIn

MORPHOGENIC PHASE. "Did evolution really have an early 'morphogenic' phase during which most major body plans originated?" https://lnkd.in/d-B5nwz View in LinkedIn

HETEROCHRONY. "De Beer presented a mechanistic explanation by which changes in the timing of developmental events in the descendant as contrasted with the ancestor could yield evolutionary novelties by changing the relations of developmental features." https://lnkd.in/d2_xbfe View in LinkedIn

EVOLUTIONARY DEVELOPMENT. "It was already clear that the course of development, or ontogeny, of an organism is the product both of selection acting on mechanisms of development and of the evolutionary history of its particular lineage." https://lnkd.in/d2_xbfe View in LinkedIn

CAMBRIAN EXPLOSION. https://lnkd.in/dG9YQPv View in LinkedIn

CAMBRIAN TRANSFORMATION. "Numerous phyla were present in the early Cambrian, whereas before the base of the Cambrian (dated at 543 My ago) only the enigmatic Ediacaran animals are found." https://lnkd.in/d-B5nwz View in LinkedIn

CARNIVAL OF THE WIERD AND WONDERFUL. "Some 13 separate phyla are represented in these faunas including some very weird animals such as Anomalocarus, Hallucigenia, Opabinia, Odontogriphus and Wiwaxia. The apparent, sudden appearance of this carnival of the animals suggested a real explosion of new body plans or perhaps the animals had just acquired skeletons and the optimum size to be detected in the fossil record." https://lnkd.in/daSxgHq View in LinkedIn

BEYOND COMPARE. "Stephen Jay Gould in his best-selling book, Wonderful Life: The Burgess Shale and the Nature of History, noted the sudden appearance of these very distinctive types of animal, suggesting that the Cambrian explosion was a time of great experimentation never again repeated. Modern statistical analyses have not confirmed Gould’s hypothesis. Rather the animals look different and odd because they are difficult to compare with our modern fauna; living arthropods are just as different from each other as those of the Cambrian." https://lnkd.in/daSxgHq View in LinkedIn

NO NEW PHYLA. "Despite the enormous amount of developmental and morphological innovation that has occurred since then within body plans, no new phyla appear to have originated since the Cambrian. Nonetheless, enormous evolutionary changes have gone on within the animal kingdom within these long-conserved underlying patterns." https://lnkd.in/d2_xbfe View in LinkedIn