Exam 8: Principles of Development

When the central mass of yolk restricts cleavage to the surface of the egg,and 8 rounds of mitosis without cytoplasmic division pepper the surface with nuclei that eventually are enclosed,this is ______ cleavage.

A characteristic of development of Deuterostomia is

In mammals,the organ of exchange between the mother and fetus is the

An enterocoelous animal has

The nervous system of vertebrates develops from which germ layer?

The cortical reaction that follows fertilization causes a hardening of the vitelline envelope to produce the _________ _________.

Entrance of more than one sperm

The effect of yolk on cleavage is that

A developmental stage comprised of a hollow ball of cells is the

The placenta develops from

A primitive streak appears during gastrulation of

Throughout the descriptions of the various major animal taxa,the type of cleavage and the origin of the coelom are of foremost importance.Why are such esoteric developmental features central to classification compared to other prominent anatomical and physiological features that are only mentioned for a few major taxa?

The difference between schizocoelous and enterocoelus organisms is

Which of the following is NOT characteristic of regulative development in animals?

In land vertebrates,the function of the chorion is to

The sac that surrounds the fetus and usually ruptures just before childbirth is the

In animals,indirect development

Evolutionary Developmental Biology (Evo-Devo)is a relatively new field that links the study of evolution to the study of development.Which statement below is best supported by the emerging principles of Evo-Devo?

The allantois

The concept that an egg or sperm cell contained a very small but fully developed individual was called