Name _____________________________________________ Date __________ Period ______
Unit 3, Descriptive Embryology, Review Packet
Directions: Read the statements below and circle the correct answer choice.
1. Most biologists of the 17th and 18th centuries believed in ____________, the concept
that gametes contain miniaturized versions of all of the elements present in the adult.
A. biogenesis
B. epigenesis
C. preformation
D. spontaneous generation
2. The study of animal development from the fertilized egg to the formation of all major
organ systems is called _____________.
A. comparative anatomy
B. entomology
C. embryology
D. molecular biology
3. The specialized organelle at the head of the sperm that releases lysins is called
______________.
A. the vitelline llayer
B. a mitochondrion
C. microvilli
D. the acrosome
4. Egg activation is a series of biochemical changes in the egg that ensures the
completion of fertilization and initiates embryonic development.
A. true
B. false
5. A protective envelope that forms around a fertilized egg is known as
______________.
A. a fertilization membrane
B. an acrosome
C. the egg cortex
D. the vitelline layer
6. The region of the zygote referred to as the ______________ contains less yolk and
is more metabolically active than the opposite pole.
A. North Pole
B. South Pole
C. vegetal pole
D. animal pole
7. What are cell divisions during embryonic development called?
A. blastulas
B. cleavages
C. meiosis
D. gastrulas
8. Cleavages produce blastomeres which divide synchronously for a short time.
A. true
B. false
9. Cleavages that completely divide an egg are _______________.
A. meroblastic
B. semi-blastic
C. holoblastic
D. blastocoels
10. ___________ forms the inner lining of the digestive cavity of an embryo.
A. Ectoderm
B. Mesoderm
C. Endoderm
D. Blastoderm
11. ___________ forms muscle, blood, skeletal elements and other connective tissues.
A. Ectoderm
B. Mesoderm
C. Endoderm
D. Blastoderm
12. In vertebrates, the ectoderm forms nervous tissue, sensory organs, and the gut
tract lining.
A. true
B. false
13. A stage of embryology usually consisting of a hollow ball of cells is called the ____.
A. morula
B. blastula
C. gastrula
D. archenteron
14. Invagination or involution of cells in embryo occurs during a process called ______.
A. gastrulation
B. neurulation
C. blastulation
D. epiboly
15. Which of the following characteristics are true of all chordates?
A. dorsal, tubular nerve cord
B. notochord
C. pharyngeal slits or pouches
D. postanal tail
E. all of the above
16. Vertebrates are not members of the phylum Chordata.
A. true
B. false
17. Animals with a vertebral column are known as ____________.
A. chordates
B. invertebrates
C. vertebrates
D. echinoderms
18. A process in which the ectoderm spreads over the entire embryo is known as ____.
A. epiboly
B. polyploidy
C. diploid
D. haploid
19. The development from a nondescript form in the early embryo to their form in late
embryonic development is known as ________________________.
A. primary germ layers
B. holoblastic
C. meroblastic
D. differentiation
20. The ________ is the outermost extra-embryonic membrane of the embryo.
A. allantois
B. amnion
C. ectoderm
D. chorion
21. In their feeding habits, zebrafish are characterized as ____________.
A. carnivores
B. omnivores
C. herbivores
22. Female zebrafish lay eggs that are then fertilized by the male. This is known as
_________.
A. internal fertilization
B. external fertilization
C. parthenogenesis
D. sexual dimorphism
23. Which of the following is the correct sequence of the stages of development in
zebrafish?
A. zygote, cleavage, blastula, gastrula, segmentation, pharyngula, hatching
B. zygote, blastula, cleavage, gastrula, segmentation, pharyngula, hatching
C. cleavage, zygote, blastula, gastrula, segmentation, pharyngula, hatching
D. zygote, cleavage, blastula, gastrula, pharyngula, segmentation, hatching
24. What is the main event of the cleavage period in zebrafish?
A. a diploid zygote is formed
B. cells cleave to form an embryo with 64 cells
C. germ layers of the embryo form
D. the pharyngeal region develops
25. What is the main event of the segmentation period in zebrafish?
A. a diploid zygote is formed
B. the pharyngeal region develops
C. the embryo develops a spine and the features of a chordate
D. germ layers of the embryo form
26. What is the main event of the gastrula period in zebrafish?
A. a diploid zygote is formed
B. cells cleave to form an embryo with 64 cells
C. germ layers of the embryo form
D. the embryo develops a spine and the features of a chordate
27. What is the main event of the blastula period in zebrafish?
A. epiboly begins
B. cells cleave to form an embryo with 64 cells
C. germ layers of the embryo form
D. the pharyngeal region develops
28. What is the main event of the hatching period in zebrafish?
A. a diploid zygote is formed
B. a fluid-filled cavity called a blastocoel forms
C. the embryo breaks free from the chorion
D. germ layers of the embryo form
29. On average, how many days after fertilization does it take a zebrafish to hatch?
A. three to four
B. five to eight
C. nine to eleven
D. twelve to fifteen
30. Examine the picture to the right. In what stage would this
zebrafish embryo be placed?
A. blastula
B. cleavage
C. gastrula
D. zygote
31. Examine the picture to the right. In what stage would this
zebrafish embryo be placed?
A. blastula
B. gastrula
C. pharyngula
D. segmentation
32. Examine the picture to the right. In what stage
would this zebrafish embryo be placed?
A. gastrula
B. hatching
C. pharyngula
D. segmentation
33. Examine the picture to the right. In what stage would this sea
star embryo be placed?
A. zygote
B. cleavage
C. morula
D. blastula
E. gastrula
34. Examine the picture to the right. In what stage would this
sea star embryo be placed?
A. zygote
B. cleavage
C. morula
D. blastula
E. gastrula
35. Examine the picture to the right. In what stage would this
sea star embryo be placed?
A. zygote
B. cleavage
C. morula
D. blastula
E. gastrula
36. Which of the following is the correct order of the stages of a sea star embryo?
A. blastula, gastrula, morula, zygote, cleavage, bipinnaria larva
B. zygote, blastula, cleavage, gastrula, morula, bipinnaria larva
C. zygote, cleavage, blastula, morula, gastrula, bipinnaria larva
D. zygote, cleavage, morula, blastula, gastrula, bipinnaria larva
37. In the sea star embryo, a solid ball of 16-64 cells is known as a ______________.
A. blastula
B. gastrula
C. morula
D. zygote
38. A zygote is a fertilized egg.
A. true
B. false
39. Examine the picture below of early cleavage patterns. Which would be
representative of the early cleavage pattern in sea stars?
A. row A
B. row B
C. row C
40. Which of these embryos has a large quantity of yolk?
A. row A
B. row B
C. row C
D. none of the above
Questions 39 & 40