Before writing, take the time to read through the exam.  Print your name and student number at the top of each page.  Write in ink.  Feel free to employ diagrams in your answers. Total marks = 60
 
QUESTIONS

1. Briefly list and describe (ONLY a few words to a SHORT sentence each) the three 17th century theories devised to account for the origin of life during animal development.(6 marks)

a)
 

b)
 

c)
 

2. The acrosomal vesicle and cortical granules are found in the male and female germ cells respectively.  List some of the attributes which they have in common (4 marks):

a)      b)
 

c)      d)
 
 

3. Briefly define the term genomic imprinting and give one example of an imprinted locus. (1 marks).
 
 
 
 
 
 

4. A new animal species has recently been found lurking in the basement of the biology building: Homo professorius (ssp. eccentricicas).  The eggs produced by this species are large and easy to culture.  Using diagrams briefly describe how one might go about determining whether or not the oocytes possess the capacity for a fast block to polyspermy (8 marks). (More space on next page)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

5. Match the name with the scientific contribution (6 marks):

van Leeuwenhoek _____   A. filament forms between sperm and         egg (saw acrosome reaction)

Bonnet   _____   B. Animal/vegetal gradients in sea urchin

von Baer  _____   C. conserved phylotype during
       embryogenesis

Chambers  _____   D. animalcules

von Kolliker  _____   E. parthenogenesis in aphids

Holtfreter  _____   F sperm develop in seminiferous         tubules and are not parasites

      G. sewed waxed shorts for his frogs

      H. jelly coat stimulates acrosome reaction        in sea urchin sperm

 6. There are three major hypothesis regarding why imprinting evolved.  What evolutionary benefits might be conferred by imprinting in  mammals (3 marks)?

a

b

c

7. What sort of egg yolk distribution and pattern of cleavage occur in Drosophila?   (2 marks).
 
 
 

8.  If Stocum and Crawford treated a distal (wrist level) regeneration blastema with retinoic acid (vitamin A) before grafting them onto a proximal host blastema, what was the result in terms of both the form of the regenerate and the level of its emergence from the host stump? (2 marks)
 
 
 
 
 
 
 

b. How might one clone a gene which turns on early in specific response to Vitamin A treatment? (5 marks)
 
 
 
 

9. What similarities are shared by Hensen’s node and an amphibian dorsal lip? (4 marks)
 
 
 
 
 
 

10. Use dorsal-view labeled diagrams to show the placement of and direction (anterior to posterior) of formation of the following structures in frog. (4 marks)

a.  Dorsal lip (Mid-gastrula)    b.  Notochord
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

11.  Imagine you were setting up a series of experiments to test the role of siamois in frog development.  What result would you expect in each of the following instances:
a) inject siamois mRNA into ventral vegetal blastomeres (1 mark)
 
 
 

b)inject siamois mRNA into dorsal vegetal blastomeres (1 mark)
 
 
 

c)inject a siamois antagonist (perhaps a mutated and inactive form of siamois) into one cell-stage embryos. (1 mark)
 
 
 

d) UV irradiated embryo (1 mark)
 
 
 

e)UV irradiated embryo later injected with siamois in a vegetal blastomere. (1 mark)
 
 
 

12.  Nature is parsimonious: genetic networks tend to be utilized over and over again throughout both evolution and development.  Describe where one gene performs a patterning role in either two different organisms or at two different times during the development of a single embryo.  Be sure to place the gene and its product within a context which includes the names of other genes involved, and similarities in structures which arise. (8 marks)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

13. Loss of cleavage synchrony is usually a signpost for a major transition during blastulation.  What starts to occur during this phase of development (2 Marks).