Chapter 22 Evolution

What is the "moment of conception"?

Fusion of the male and female pronuclei

Germ-layer formation results from the process of __________.

Gastrulation

Which of the following is NOT a factor that opposes the calming effect of progesterone on uterine smooth muscle (the myometrium) and may lead to the onset of labor?

Increasing relaxin levels

What is the extra-embryonic membrane that gives rise to the urinary bladder?

allantois

The fusion of male and female pronuclei is termed __________.

amphimixis

What event marks the onset of development?

fertilization

Given that albinism is a recessive trait, if an albino mother and a normal father with the genotype AAhave a child, that child will __________.

have normal coloration

The stretching of the myometrium is associated with a gradual increase in the __________.

rates of spontaneous smooth muscle contractions

The umbilical cord, or umbilical stalk, contains __________.

the allantois, blood vessels, and yolk stalk

The Extra-embryonic membranes that develop from the endoderm and the mesoderm are the __________.

yolk sac and the amnion

What is the meaning of the term gestation?

All of prenatal development

What is the correct sequence of events going from the zygote to the fetus?

Cleavage; implantation; placentation; embryogenesis

Which of the following is not a reason why maternal blood volume increases during pregnancy?

Decreased maternal PCO2

Which of the following does NOT happen during oocyte activation?

The first cleavage is completed.

What happens in the process of hatching?

The zona pellucida is shed from the blastocyst.

Embryogenesis is the process that establishes the foundation for __________.

all the major organ systems

Gastrulation produces three germ layers. Which of the following is not one of those layers?

blastocoele

A hollow ball of cells created by cleavage is called a __________.

blastocyst

Which of the following forms the placenta?

chorion

During gestation, the primary compensatory adjustments include all of the following except ______________.

decreasing the respiratory rate and tidal volume

The chorion develops from the __________.

mesoderm and the trophoblast

Alterations in genetic activity during development result from __________.

the differences in the cytoplasmic compositions of individual cells