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Garstang's Paedomorphosis Hypothesis

Walter Garstang - Wikipedia

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Chapter 23: Question 10 - Zoology

Atherosclerotic lesions also develop innormolipidemic rabbits as a result of repeated, or continuousintimal injury by catheters or balloons, or by nitrogen exposure().The pig is a very good model to study CVD as it hasa human-like cardiovascular anatomy ().

In 1928 Walter Garstang hypothesized that tunicates resemble the ancestral stock of the vertebrates

The larvae of the invertebrate chordates (tunicates and amphioxus) are secondary larvae whose relation to the primary dipleurula-type larvae of echinoderms and hemichordates is somewhat obscure. Past authorities have argued that chordates actually derive from motile larvae that have evolved to become sexually mature (paedomorphosis). One such proposal, more specific in its predictions than most, is due to Walter Garstang: he noted the topological similarity between dipleurula ciliary bands (which have their own innervation) and chordate neural plate, and suggested that the latter actually derive from the former. While there is as yet no convincing evidence that chordates are directly derived from the body of a dipleurula-type larva, the core of the idea, that there is continuity in the neurogenic tissues, has some appeal. It is a surprisingly parsimonious way of deriving a characteristic chordate structure, the neural tube, whose origin is otherwise unexplained.

garstang’s theory | All you need is Biology

Posts about garstang’s theory written by Marc Arenas Camps

Third, all four remaining features (a notochord, a dorsal neural tube, myotomes and a postanal tail) are deeply associated with the evolution of FT larvae, a new larval type that swims using a beating tail. The occurrence of FT larvae within deuterostomes (not by changing the form of dipleurula or auricularia-like larvae) is therefore critical to understanding chordate origins. It should be emphasized that all structures are formed through embryogenesis until larval formation. This suggests that an embryological comparison between non-chordate (e.g. acorn worms) and chordate deuterostomes (e.g. lancelets) might be the first step to elucidate developmental mechanisms of chordate origin, as structures corresponding to a dorsal neural tube and notochord never develop in acorn worm embryos. The postanal tail is likely to be associated with formation of the so-called ‘tailbud’, which probably functions as an organizer for tail elongation in chordate embryos []. Therefore, it is wiser to ask how these structures are newly formed in chordate embryos rather than to seek possible homologies with other structures of acorn worm embryos and larvae.

What is Gastrang's hypothesis? What does it state? | …

14/06/2006 · Best Answer: You spelled it wrong..

Walter Garstang: a retrospective | SpringerLink
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