Choose the correct developmental sequence of animal development.
A) organogenesis → cleavage → fertilization → gastrulation
B) gastrulation → cleavage → fertilization → organogenesis
C) cleavage → gastrulation → organogenesis → fertilization
D) fertilization → cleavage → gastrulation → organogenesis
E) cleavage → fertilization → gastrulation → organogenesis
D
The first stage of embryonic development is _____. This process produces _____.
A) neurulation ... a neurula
B) gastrulation ... a three-layered embryo
C) cleavage ... a cluster of cells
D) parturition ... a fetus
E) ovulation ... a zygote
C
The formation of the fertilization envelope requires an increase in the availability of _____.
A) sodium ions
B) potassium ions
C) hydrogen ions
D) calcium ions
D
During fertilization, the acrosomal contents _____.
A) block polyspermy
B) digest the protective jelly coat on the surface of the egg
C) trigger the completion of meiosis by the sperm
D) help propel more sperm toward the egg
B
In mammalian eggs, the receptors for sperm are found in the _____.
A) cytosol of the egg
B) mitochondria of the egg
C) egg plasma membrane
D) fertilization membrane
C
Which of the following correctly displays the sequence of developmental milestones?
A) blastula → gastrula → cleavage
B) cleavage → blastula → gastrula
C) gastrula → blastula → cleavage
D) cleavage → gastrula → blastula
B
The mesoderm gives rise to _____.
A) the central nervous system
B) skeletal and muscular systems
C) the gastrointestinal tract and pancreas
D) the lining of the lungs
E) jaws and teeth
B
Birds, reptiles, and mammals are called "amniotes" because _____.
A) their embryos lack an allantois to collect and store metabolic wastes
B) they have extra-embryonic membranes that develop an aqueous environment in which development occurs
C) they give rise to cells that form the nervous system
D) they digest yolk and form a network of blood vessels to distribute nutrients to the embryo
E) they transport oxygen to the embryo
B) they have extra-embryonic membranes that develop an aqueous environment in which development occurs
Embryonic cells especially active in assuring nutritional exchange between a pregnant woman and her embryo are found in the _____.
A) ectoderm
B) hypoblast
C) epiblast
D) trophoblast
E) inner cell mass
D
Cells move to new positions as an embryo establishes its three germ-tissue layers during _____.
A) induction
B) gastrulation
C) cleavage
D) determination
B
The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is _____.
A) endoderm → ectoderm → mesoderm
B) ectoderm → endoderm → mesoderm
C) ectoderm → mesoderm → endoderm
D) mesoderm → endoderm → ectoderm
C
If gastrulation was blocked by an environmental toxin, then _____.
A) cleavage would not occur in the zygote
B) the blastula would not be formed
C) the blastopore would form above the gray crescent in the animal pole
D) embryonic germ layers would not form
D
At the time of implantation, the human embryo is called a _____.
A) blastocyst
B) fetus
C) gastrula
D) zygote
A
Uterine implantation due to enzymatic digestion of the endometrium is initiated by the _____.
A) inner cell mass
B) mesoderm
C) endoderm
D) trophoblast
D
The embryonic precursor to the human spinal cord is the _____.
A) notochord
B) archenteron
C) neural tube
D) mesoderm
C
The cortical reaction of sea urchin eggs functions directly in
A) the production of a fast block to polyspermy.
B) the release of hydrolytic enzymes from the sperm.
C) the fusion of egg and sperm nuclei.
D) the generation of an electrical impulse by the egg.
E) the formation of a fertilization envelope.
E) the formation of a fertilization envelope.