Exercise 11.3 - Ascaris Oogenesis
Figure 11.7 Ascaris maturation
- Prepared slides of Ascaris megalocephala maturation
- Place the slide(s) of Ascaris on the microscope and
focus on the eggs within the body.
Unlike the grasshopper testis where division is continuous, the
ascaris egg halts its meiotic division until fertilized by a
sperm. Subsequently, the final stages of meiosis are completed
and nuclear fusion occurs. Within an average cross section of the
female, it is usually possible to observe all of the stages of
meiosis and early cleavage.
- Using Figure 11.7 as a guide, identify, draw and label the
First polar body formation (first maturation division)
Second polar body formation (second maturation division)
Pronuclear stage (fusion of egg and sperm nuclei)
First cleavage division (beginning of mitosis)
- Note the presence of any spindle fibers, and the shape and
location of the chromosomes during each phase of development.
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Cell Biology Laboratory Manual
Dr. William H. Heidcamp, Biology Department, Gustavus Adolphus College,
St. Peter, MN 56082 -- firstname.lastname@example.org