Download 47_InstGuide_AR

Chapter 47
Animal Development
Teaching Objectives
The Stages of Embryonic Development in Animals
1. Compare the concepts of preformation and epigenesis.
2. List the two functions of fertilization.
3. Describe the acrosomal reaction and explain how it ensures
that gametes are conspecific.
4. Describe the cortical reaction.
5. Explain how the fast and slow blocks to polyspermy function
sequentially to prevent multiple sperm from fertilizing the
egg.
6. Describe the changes that occur in an activated egg and
explain the importance of cytoplasmic materials to egg
activation.
7. Compare fertilization in a sea urchin and in a mammal.
8. Describe the general process of cleavage.
9. Explain the importance of embryo polarity during cleavage.
Compare the characteristics of the animal hemisphere,
vegetal hemisphere, and gray crescent in amphibian
embryos.
10. Describe the formation of a blastula in sea urchin,
amphibian, and bird embryos. Distinguish among
meroblastic cleavage, holoblastic cleavage, and the
formation of the blastoderm.
11. Describe the product of cleavage in an insect embryo.
12. Describe the process of gastrulation and explain its
importance. Explain how this process rearranges the
embryo. List adult structures derived from each of the
primary germ layers.
13. Compare gastrulation in a sea urchin, a frog, and a chick.
14. Describe the formation of the notochord, neural tube, and
somites in a frog.
15. Describe the significance and fate of neural crest cells.
Explain why neural crest cells have been called a “fourth
germ layer.”
16. List and explain the functions of the extraembryonic
membranes in reptile eggs.
17. Describe the events of cleavage in a mammalian embryo.
Explain the significance of the inner cell mass.
18. Explain the role of the trophoblast in implantation of a
human embryo.
19. Explain the functions of the extraembryonic membranes in
mammalian development.
The Cellular and Molecular Basis of Morphogenesis
and Differentiation in Animals
20. Describe the significance of changes in cell shape and cell
position during embryonic development. Explain how these
cellular processes occur. Describe the process of
convergent extension.
21. Describe the role of the extracellular matrix in embryonic
development.
22. Describe the locations and functions of cell adhesion
molecules.
23. Describe the two general principles that integrate our
knowledge of the genetic and cellular mechanisms
underlying differentiation.
24. Describe the process of fate mapping and the significance
of fate maps.
25. Describe the two important conclusions that have resulted
from the experimental manipulation of parts of embryos and
the use of fate maps.
26. Explain how the three body axes are established in early
amphibian and chick development.
27. Explain the significance of Spemann’s organizer in
amphibian development.
28. Explain what is known about the molecular basis of
induction.
29. Explain pattern formation in a developing chick limb,
including the roles of the apical ectodermal ridge and the
zone of polarizing activity.
30. Explain how a limb bud is directed to develop into either a
forelimb or a hind limb.
Student Misconceptions
1. Some students think of fertilization as a mechanical drilling
of sperm into egg. Emphasize to your students the complex
choreography of the events of fertilization, in which contact
between conspecific egg and sperm initiates a series of
metabolic reactions within egg and sperm that trigger the
onset of embryonic development.
2. As with any complex biological process, some students find
it easier to learn the complex details than to understand the
significance of the events of development. Ensure that your
students know the events, but also understand the
significance of cleavage, gastrulation, and organogenesis in
animal development.
3. Students may not appreciate the importance of gastrulation
and the reorganization that allows the germ layers in the
gastrula to interact with each other in new ways. Remind
them of Lewis Wolpert’s famous quote: “It is not birth,
marriage, or death, but gastrulation, which is truly the most
important time in your life.”
4. Many students have great difficulty visualizing the events of
development, especially the rearrangements of cell layers
during gastrulation and neurulation. Use models and timelapse film to help students understand these complex
events.
5. Students may find it difficult to appreciate the homology of
the four extraembryonic membranes in mammals and
reptiles. Ensure that your students understand the common
ancestry of these membranes, despite their derived
structure and function in mammals.
Chapter Guide to Teaching Resources
Overview: A body-building plan for animals
Concept 47.1 After fertilization, embryonic development proceeds through
cleavage, gastrulation, and organogenesis
Transparencies
Figure 47.3 The acrosomal and cortical reactions during sea
urchin fertilization
Figure 47.4 What is the effect of sperm binding on Ca21
distribution in the egg?
Figure 47.5 Timeline for the fertilization of sea urchin eggs
Figure 47.6 Early events of fertilization in mammals
Figure 47.8 The body axes and their establishment in an
amphibian
Figure 47.9 Cleavage in a frog embryo
Figure 47.10 Cleavage in a chick embryo
Figure 47.11 Gastrulation in a sea urchin embryo (layer 1)
Figure 47.11 Gastrulation in a sea urchin embryo (layer 2)
Figure 47.11 Gastrulation in a sea urchin embryo (layer 3)
Figure 47.12 Gastrulaton in a frog embryo
Figure 47.13 Gastrulation in a chick embryo
Figure 47.14 Early organogenesis in a frog embryo
Figure 47.15 Organogenesis in a chick embryo
Figure 47.16 Adult derivatives of the three embryonic germ
layers in vertebrates
Figure 47.17 Extraembryonic membranes in birds and other
reptiles
Figure 47.18 Four stages in early embryonic development of a
human
Instructor and Student Media Resources
Activity: Sea urchin development
Video: Sea urchin embryonic development
Investigation: What determines cell differentiation in the sea
urchin?
Activity: Frog development
Video: Frog embryo development
Video: C. elegans embryo development (time-lapse)
Video: Ultrasound of human fetus 1
Video: Ultrasound of human fetus 2
Concept 47.2 Morphogenesis in animals involves specific changes in cell
shape, position, and adhesion
Transparencies
Figure 47.19 Change in cellular shape during morphogenesis
Figure 47.20 Convergent extension of a sheet of cells
Concept 47.3 The developmental fate of cells depends on their history and
on inductive signals
Transparencies
Figure 47.23 Fate mapping for two chordates
Figure 47.24 How does distribution of the gray crescent at the
first cleavage affect the potency of the two
daughter cells?
Figure 47.25 Can the dorsal tip of the blastopore induce cells in
another part of the amphibian embryo to change
their developmental fate?
Figure 47.26 Vertebrate limb development
Figure 47.27 What role does the zone of polarizing activity
(ZPA) play in limb pattern formation in
vertebrates?
For additional resources such as digital images and lecture
outlines, go to the Campbell Media Manager or the Instructor
Resources section of www.campbellbiology.com.
Key Terms
acrosomal reaction
acrosome
allantois
amnion
amniote
animal pole
apical ectodermal ridge (AER)
archenteron
blastocoel
blastocyst
blastoderm
blastomere
blastopore
blastula
cadherins
cell adhesion molecules (CAMs)
cell differentiation
chorion
cleavage
convergent extension
cortical granules
cortical reaction
cytoplasmic determinants
dorsal lip
ectoderm
endoderm
extraembryonic membranes
fast block to polyspermy
fate map
fertilization envelope
gastrula
gastrulation
germ layers
gray crescent
holoblastic cleavage
induction
inner cell mass
invagination
involution
meroblastic cleavage
mesoderm
morphogenesis
morula
neural crest
neural tube
notochord
organogenesis
pattern formation
positional information
primitive streak
slow block to polyspermy
somites
totipotent
trophoblast
vegetal pole
yolk
yolk plug
yolk sac
zona pellucida
zone of polarizing activity (ZPA)
Word Roots
acro- 5 the tip (acrosomal reaction: the discharge of a sperm’s
acrosome when the sperm approaches an egg)
arch- 5 ancient, beginning (archenteron: the endoderm-lined
cavity, formed during the gastrulation process, that develops
into the digestive tract of an animal)
blast- 5 bud, sprout; -pore 5 a passage (blastopore: the
opening of the archenteron in the gastrula that develops into
the mouth in protostomes and the anus in deuterostomes)
blasto- 5 produce; -mere 5 a part (blastomeres: small cells of
an early embryo)
cortex- 5 shell (cortical reaction: a series of changes in the
cortex of the egg cytoplasm during fertilization)
ecto- 5 outside; -derm 5 skin (ectoderm: the outermost of the
three primary germ layers in animal embryos)
endo- 5 within (endoderm: the innermost of the three primary
germ layers in animal embryos)
epi- 5 above; -genesis 5 origin, birth (epigenesis: the
progressive development of form in an embryo)
extra- 5 beyond (extraembryonic membrane: four membranes
that support the developing embryo in reptiles, birds, and
mammals)
fertil- 5 fruitful (fertilization: the union of haploid gametes to
produce a diploid zygote)
gastro- 5 stomach, belly (gastrulation: the formation of a
gastrula from a blastula)
holo- 5 whole (holoblastic cleavage: a type of cleavage in which
there is complete division of the egg)
in- 5 into; vagin- 5 a sheath (invagination: the infolding of cells)
involut- 5 wrapped up (involution: cells rolling over the edge of
a lip into the interior)
mero- 5 a part (meroblastic cleavage: a type of cleavage in
which there is incomplete division of yolk-rich egg,
characteristic of avian development)
meso- 5 middle (mesoderm: the middle primary germ layer of
an early embryo)
morul- 5 a little mulberry (morula: a solid ball of blastomeres
formed by early cleavage)
noto- 5 the back; -chord 5 a string (notochord: a long, flexible
rod that runs along the dorsal axis of the body in the future
position of the vertebral column)
poly- 5 many (polyspermy: fertilization by more than one sperm)
soma- 5 a body (somites: paired blocks of mesoderm just
lateral to the notochord of a vertebrate embryo)
tropho- 5 nourish (trophoblast: the outer epithelium of the
blastocyst, which forms the fetal part of the placenta)
zona 5 a belt; pellucid- 5 transparent (zona pellucida: the
extracellular matrix of a mammalian egg) Instructor’s Guide for
Campbell/Reece Biology, Seventh EditionChapter 47 Animal
Development
Instructor’s Guide for Campbell/Reece Biology, Seventh
EditionChapter 47 Animal Development
Biology, Seventh Edition
Instructor’s Guide for Campbell/Reece