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TLS Online TPP Program

#Id: 7044

Orthogenesis - “Straight-line evolution,” held that the variation that arises is directed toward fixed goals.

#Unit 11. Evolution and Behavior #Emergence of evolutionary thoughts #Part B Pointers
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TLS Online TPP Program

#Id: 122

#Unit 5. Developmental Biology

In the initiation of the vertebrate eyes, paired regions of the brain bulges (optic vesicles, act as inducer) out and approach the surface ectoderm (act as responder) of the head.
TLS Online TPP Program

#Id: 123

#Unit 5. Developmental Biology

The head ectoderm is competent to respond to the paracrine factors made by the optic vesicles & induced to form the lens of the eye.
TLS Online TPP Program

#Id: 124

#Unit 5. Developmental Biology

The optic vesicle is able to induce lens formation in the anterior ectoderm but not in the presumptive trunk and abdomen.
TLS Online TPP Program

#Id: 125

#Unit 5. Developmental Biology

If the optic vesicle is removed, the surface ectoderm forms either an abnormal lens or no lens at all.
TLS Online TPP Program

#Id: 126

#Unit 5. Developmental Biology

The prospective lens cells secrete paracrine factors that instruct the optic vesicle to form the retina. 
TLS Online TPP Program

#Id: 164

#Unit 5. Developmental Biology

The two major parts of the eye (lens and retina) co-construct each other, and the eye forms from reciprocal paracrine interactions.