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File:Ancestors.gif
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Description & Sources
Continuity and derivations of life forms between sponge and human male.
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Orientation : Inside / outside. First stage of polycellular organism.
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Animation and coordination : Invention of muscle and nervous cells. Mouth and stomach.
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Swimming worm. Bilateral symmetry. Segmentation. First internal organs.
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Primitive Cephalochordata, formation of the spine. Differentiation of internal organs.
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Skull (with eye) and spine is complete. Vertebrata : the nervous system is complete.
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Formation of the Jaw. - Differentiation of fins. Chondrichthyes stage
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Typical fish - Invention of bones and scales, the fins have complex musculation and articulations. The lateral fins will evolve to become limbs.
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The fins evolve to fleshy members. Apparition or differentiation of lungs? First land movements?
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Formation of the neck. Fingers appear - movement and prehension ability.
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Land conquest. Lungs are functional, but the animal is still water-dependent for reproduction. (this one should be a salamander, not a lizard, but the general outlook is OK)
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Dry skin and water-independence of Amniote. (this one should be a lizard, not a salamander, but the general outlook is OK)
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Hair and gestation invention. Primitive mammalia are but insect-eaters "hairy lizards"... this one's cute, isen't it?
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Living in trees, our ancestors gained an opposable thumb and binocular frontal vision.
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(I needed an intermediary picture for smoother transition, so...) Higher monkey - social interaction and communication probably increased at that time. Ability to awkwardly walk on two feet.
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(I needed yet another intermediary picture for smoother transition, sorry) Our nearest cousin - lost its tail, by the way.
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Vertical position frees the brain and the hand.
Summary
Description | Evolution line from sponge to man |
Date | 1 January 2007 |
Source | Own work |
Author | Michelet-密是力 ( talk) |
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