If you transplant trunk neural crest into the cranial neural crest region of a developing embryo, will you see the donor tissue form cartilage? Does the neural crest only give rise to two cells in the developing embryo, and is essential for lamprey to develop their jaw structure? Does a multipotent neural crest cell that is receiving Wnt signals become a Chromaffin cell?

View this slideshow (http://openstaxcollege.org/l/stemcells) to learn more about stem cells. How do somatic stem cells differ from embryonic stem cells?

Which of the following are mismatched? (a) endoderm; lining of the digestive tube (b) ectoderm; circulatory system (c) mesoderm; notochord (d) mesoderm; reproductive system (e) ectoderm; sense organs

In the embryonic development of the eye: a. the optic vesicle cells permanently adhere to each other to prevent movement, whereas the optic cup cells are very motile. b. the optic cup induces the surface ectoderm to form the lens placode. c. gradients determine that the ectoderm overlying the lens vesicle develops into the optic vesicle. d. microtubules powered by myosins and microfilaments powered by dyneins move the eye components around in the head region. e. cadherins function in the presence of calcium to allow the lens placode and optic cup to break apart.

Discuss Concepts Near the time of childbirth, collagen fibers in the connective tissue of the cervix break down, and gap junctions between the smooth muscle cells of the uterus increase in number. What do you think is the significance of these tissue changes?

Figure 27.9 Which of the following statements about diploblasts and triploblasts is false? Animals that display radial symmetry are diploblasts. Animals that display bilateral symmetry are triploblasts. The endoderm gives rise to the lining of the digestive tract and the respiratory tract. The mesoderm gives rise to the central nervous system.

Contrast early development, including cleavage, in the echinoderm (or in amphioxus), the amphibian, and the bird, paying particular attention to the importance of the amount and distribution of yolk.

How do the amount and distribution of cytoplasm in the fertilized egg influence early development?

How do the Hox genes of vertebrates differ from those of cephalochordates?

The olfactory pits form from which of the following? mesoderm cartilage ectoderm endoderm