Deck 8: Principles of Development

Question 1

The point of fertilization occurs when

A) sperm are deposited in the vagina.
B) sperm reach the outer jelly coating of the egg.
C) she sperm sheds the tail.
D) the sperm nucleus and egg nucleus unite to form a zygote.

Answer 1

D

Question 2

Before fertilization,as an egg cell matures,its nucleus increases RNA content and it is called

A) a pronucleus.
B) a cleavage furrow.
C) a germinal vesicle.
D) a blastomere.

Answer 2

C

Question 3

In animals,indirect development

A) occurs only in mammals.
B) lacks a larval stage.
C) involves a larval stage.
D) occurs only when eggs develop without being fertilized.

Answer 3

C

Question 4

The concept that an egg contains the building material that must somehow be assembled is called

A) induction.
B) pronuclei.
C) preformation.
D) epigenesis.

Question 5

Cleavage on the surface of the yolk of the chicken egg is partial because cleavage furrows cannot cut through; this is called

A) meroblastic.
B) holoblastic.
C) isolecithal.
D) indeterminant.

Question 6

A characteristic of development of Deuterostomia is

A) spiral cleavage.
B) mosaic development.
C) the mesoderm developing from a special blastomere called the 4d cell.
D) radial cleavage.

Question 7

What prevents a foreign species' sperm from fertilizing an egg?

A) Nothing prevents fertilization if chemical and other behavioral cues allow mating
B) Egg recognition proteins on the acrosomal process bind to specific sperm receptors on the vitelline envelope
C) The size and shape of sperm must fit the hole in the egg membrane
D) The cortical reaction by the egg actively draws in the sperm

Question 8

___________ occurs when a fertilized egg enters cell division without further growth in volume.

A) Cleavage
B) Gastrulation
C) Differentiation
D) Embryology

Question 9

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

A) induction.
B) pronuclei.
C) preformation.
D) holoblastism.

Question 10

Eggs with very little yolk that is evenly distributed in the egg are called

A) mesolecithal.
B) holoblastic.
C) isolecithal.
D) telolecithal.

Question 11

Rotational cleavage is unique to

A) amphibians.
B) mammals.
C) sea stars.
D) lophotrochozoa.

Question 12

Radial cleavage is found in

A) birds.
B) mammals.
C) most protostomes.
D) sea stars.

Question 13

Generally,only one sperm fertilizes an egg because

A) there are so few sperm that two are unlikely to arrive at the same time.
B) sperm compete and only the most fit one is accepted.
C) many sperm enter but only one set of chromosomes fuses with the egg nucleus; excess sperm are absorbed.
D) when the first sperm membrane fuses with the egg membrane, it separates the fertilization membrane and forms a barrier to other sperm.

Question 14

The product of cleavage in a zygote produces a cluster of small cells called

A) pronuclei.
B) blastomeres.
C) polar bodies.
D) meroblasts.

Question 15

Eggs with abundant yolk that is concentrated at the vegetal pole are called

A) mesolecithal.
B) holoblastic.
C) isolecithal.
D) telolecithal.

Question 16

Entrance of more than one sperm

A) is called polyspermy and is disastrous for animal zygotes.
B) results in epigenesis.
C) is neutralized by fusion with polar bodies.
D) results in formation of a large pronucleus.
E) initiates cleavage.

Question 17

Cleavage in mammals

A) is faster than most other groups.
B) does not begin, like most other animals, with a first cleavage plane through the animal-vegetal axis.
C) is asynchronous, meaning that all blastomeres do not divide at the same time.
D) is very loose, with cells drifting about in a loose amorphous, bubble-like mass.

Question 18

The response to sperm fusing with the egg membrane causes enzyme-rich granules to ultimately cause the separation of the vitelline envelope and the egg membrane; this is called

A) polyspermy.
B) pronucleation.
C) the cortical reaction.
D) cytoplasmic localization.

Question 19

The effect of yolk on cleavage is that

A) yolk promotes faster cleavage.
B) yolk promotes spiral cleavage in all cases.
C) yolk slows down and indirectly determines the type of cleavage to take place.
D) yolk is the origin of all cleavage planes.

Question 20

Eggs with a moderate amount of yolk concentrated at the vegetal pole are called

A) mesolecithal.
B) holoblastic.
C) isolecithal.
D) telolecithal.

Question 21

The special blastomere labeled the 4-d cell often gives rise to the

A) endoderm of many protostomes.
B) endoderm of many deuterostomes.
C) mesoderm of many protostomes.
D) mesoderm of many deuterostomes.
E) ectoderm of many protostomes.

Question 22

The allantois

A) becomes the chorionic villi.
B) lies next to the shell in chicks.
C) is a structure composed of two germ layers.
D) gives rise to umbilical blood vessels in humans.

Question 23

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

A) amnion.
B) placenta.
C) chorion.
D) yolk sac.

Question 24

Which is NOT an extraembryonic membrane?

A) Amnion
B) Placenta
C) Yolk sac
D) Allantois

Question 25

Superficial cleavage is found in

A) amphibians.
B) mammals.
C) sea stars.
D) insects.

Question 26

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

A) is a type in which the fate of a blastomere is heavily determined by its neighbor cells.
B) occurs in most (but not all) deuterostomes.
C) is a type in which removing a blastomere causes the remaining blastomeres to "fill in" for the lost cell.
D) usually occurs in protostomes.

Question 27

The difference between schizocoelous and enterocoelus organisms is

A) no difference at all; they are two names for the same eucoelomate structure.
B) a difference in how the true coelom forms from mesoderm, from the gut or blastopore region.
C) the difference between a pseudocoelom and a true coelom.
D) a difference between a split two-chambered coelom and an intact or enterocoelom.

Question 28

The internal pouch representing the developing gut in a gastrula is called a _______

A) blastocoels.
B) pseudocoelom.
C) coelom.
D) archenteron.

Question 29

Mosaic development in animals

A) is a type in which each of the fate of a blastomere is heavily determined by its neighbor cells.
B) is synonymous with regulative development.
C) is a type in which each of the early blastomeres lacks the potential of developing into a complete organism and removing a blastomere eliminates a future body part.
D) None of the choices are correct

Question 30

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) Radial
B) Spiral
C) Superficial
D) Trophoblastic

Question 31

The placenta develops from

A) fetal membranes only.
B) maternal tissue only.
C) both fetal and maternal tissue.
D) polar bodies that develop just the placental tissues.

Question 32

Neighboring cells influence the development of each other,either by direct contact or by production of chemical signals,in

A) neurulation.
B) induction.
C) maternal determinants.
D) homeotic pattern formation.

Question 33

An enterocoelous animal has

A) a true coelom.
B) a pseudocoelom.
C) no coelom.
D) a schizocoelom.

Question 34

"Diploblastic" refers to ________ where _________.

A) fish and amphibians, cells divide in twos synchronously
B) sea stars and humans, development can proceed in two directions
C) birds and reptiles, the egg must be completely nourished within a shell
D) cnidarians and comb jellies, only two germ layers are formed
E) only mammals, advanced neural structures are formed

Question 35

The difference between primary and secondary induction is a difference between

A) "hard-wired" commands and chance development.
B) effects of the dorsal lip organizer and effects of the subsequent cell's induction.
C) nuclear and cytoplasmic determinants.
D) homeotic pattern formation and regular structural gene effects.

Question 36

In nearly all metazoa,"germ layers" is a term that describes

A) the germ cells.
B) foreign cells that enter the embryonic process.
C) mesoderm, ectoderm and endoderm.
D) the germ line, in contrast to the somatic or body cells.

Question 37

The conclusion of Spemann's work,in which he tied off a zygote isolating the nucleus on one side and only cytoplasm on the other,helped prove

A) origin of the coelom.
B) nuclear equivalency.
C) cytoplasmic specification.
D) Embryonic induction

Question 38

A primitive streak appears during gastrulation of

A) sea stars and humans.
B) birds and reptiles.
C) nemerteans.
D) only mammals.

Question 39

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

A) blastula.
B) blastocoel.
C) gastrula.
D) neurula.

Question 40

In the human,which part of the blastocyst will develop into the embryo proper (versus the supporting placenta)?

A) Archenteron
B) Blastopore
C) Trophoblast
D) Inner cell mass

Question 41

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

Question 42

In land vertebrates,the function of the chorion is to

A) become umbilical cord.
B) enclose the entire embryonic system and then fuse to form the chorioallantoic membrane.
C) grow from the embryonic hindgut to become a repository for the wastes of metabolism.
D) surround the embryo and provide a marine environment for development.

Question 43

If yolk is primarily food storage for the developing embryo,why is it so central to understanding cleavage?

Question 44

Discuss the process of cytoplasmic specification and the role of differently pigmented cytoplasms.

Question 45

At which stage do we begin to see development of the mesoderm germ layer?

A) Gastrulation
B) Neurulation
C) Blastulation
D) Cleavage

Question 46

The nervous system of vertebrates develops from which germ layer?

A) Epiderm
B) Ectoderm
C) Endoderm
D) Mesoderm
E) Myoderm

Question 47

Distinguish "germ cells" and "germ layers."

Question 48

The major group of the animal kingdom that includes animals that in their development show spiral cleavage and mosaic development is the __________.

Question 49

Discuss the significance of Spemann's experiment that demonstrated that every blastomere contains sufficient genetic information for the development of a complete animal.

Question 50

A true coelom is a fluid-filled cavity completely lined by ___________.

Question 51

Contrast mosaic development with regulative development and indicate what animals would use each pattern of differentiation.Is one form of development "better" than another? Why or why not?

Question 52

Outline the significance of the amniotic egg.Discuss the various layers and their functions in embryogenesis.

Question 53

Animals having radial cleavage (echinoderms)also show a type of development,called __________ _________,in which separated blastomeres can develop into complete and normal organisms.

Question 54

The abnormal entrance of more than one sperm into an egg,normally prevented by the fertilization membrane,is called _______________.

Question 55

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?

Question 56

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

A) amnion.
B) placenta.
C) chorion.
D) yolk sac.
E) allantois.

Question 57

The neural tube of vertebrates develops by

A) folding of ectoderm tissue.
B) migration of mesoderm cells.
C) fusion of ectoderm and mesoderm.
D) extension of endoderm into a thin spinal column.

Question 58

Somites,which form segmental muscles and vertebrae,develop from which germ layer?

A) Ectoderm
B) Endoderm
C) Mesoderm
D) Myoderm

Question 59

In an amniotic egg,the amnion

A) serves as a repository for wastes produced by the developing embryo.
B) serves as a respiratory surface for the exchange of oxygen and carbon dioxide.
C) is a fluid-filled sac that protects the embryo from shocks and adhesions.
D) develops into the chorio-allantoic membrane.

Question 60

The concept of ________ suggested that preformed animals in the egg unfolded during development.

Question 61

Discuss the significance of the homeotic and other homeobox-containing genes that are found in one or more clusters on particular chromosomes in Drosophila.

Question 62

Discuss or outline the derivatives of endoderm,mesoderm,and ectoderm.