Exam 47: Animal Development

Just prior to the onset of gastrulation in an embryo, the "organiser" cells are specified. If you were to experimentally block the specification of these cells, what would you expect the result to be in the developing embryo?

The developmental precursors to the gonadal tissues of Caenorhabditis elegans uniquely contain ________.

If the apical ectodermal ridge is surgically removed from an embryo, it will lose ________.

The first cavity formed during frog development is the ________.

Which of the following is common to the development of birds and mammals?

The nematode Caenorhabditis elegans ________.

The term applied to a morphogenetic process whereby cells extend themselves, making the mass of the cells narrower and wider, is ________.

The primitive streak in a bird is the functional equivalent of ________.

The archenteron develops into

Embryonic induction, the influence of one group of cells on another group of cells, plays a critical role in embryonic development. In 1924, Hans Spemann and Hilde Mangold transplanted a piece of tissue that influences the formation of the notochord and neural tube, from the dorsal lip of an amphibian embryo to the ventral side of another amphibian embryo. If embryonic induction occurred, which of the following observations justifies the claim of embryonic induction?