02/23/11
Pre Life Assignment 2
1) The evolution of limbs and fingers
a. Did verbalism for leave the water, or did they develop limbs and fingers first?
In 1970 jennet Clark discovered early tetrapods authentic limbs and fingers before departure the water. In Greenland she found a unique lobed finned dodo proving life on land evolved subaquatic first. This primitive fossil had legs.
Acanthostega gunneri developed all keengs necessary for life to sustain underwater including its two-lobed brain, petal like hands, a tail used for swimming, lungs and gills. This conjecture believes the structures of its hips were attached weakly to its spine, and its short limbs were used for propulsion. Also, short and thin ribs were incapable of protecting its vital organs (Murphy, C. Dennis Devonian Times- Acanthostega gunneri)) would be repugnant for life on land. Acanthostega had the ancestral notorchord spine that flexible and rod-shaped, prototype for swimming.
This amazing discovery helps demonstrates an interlocking spine, fingers and toes and even how vital organs evolved from early tetrapods. Clarks discovery changed the way we now look at pre historic life, as it is a life bulky debate that may never be Absolutely accepted.
b. What is a tetrapod?
All land-living vertebrate animals be tetrapods, having legs or appendages that resemble legs. Kangeroos, apes, elephants and dogs are tetrapods. Two legged animals like human and birds are also tetrapods. All these creatures, living or extinct, descended from early tetrapods that developed limbs from underwater. This would also include many animals that have return to the sea such as dolphins, turtles, whales that have lost their limbs from their tetrapod ancestors.
Dinosaurs are too, tetrapods, the early being from the Devonian period about 360 million years ago. primal tetrapods habitats would be in shallow swampy areas that were alter with freshwater land plants. By the late Devonian the...If you want to rag a full essay, order it on our website: Ordercustompaper.com
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