Download Unisexual reproduction in Vertebrates AP Biology Extra Credit

Unisexual reproduction in Vertebrates AP Biology Extra Credit
Name______________________
Use the article linked under Monday (11/24) or Tuesday (11/25) on our website to answer the questions below.
Questions marked with an “*” represent questions that relate to the article but might require your own thinking,
or outside sources to answer. These questions are due on Friday 12/05.
1.
How many taxa of vertebrates are known to reproduce using parthenogenesis or other similar methods?
2. What assumption does the article suggest is ‘called into question’ by growing knowledge of unisexual
vertebrates?
3. What is TRUE Parthenogenesis?
4. What is the only vertebrate group in which it is known to occur?
5. Why have parthenogenic species been considered an evolutionary “dead end.”
6. In the passage “…recombine and generate new combinations of traits is absent in clonally reproducing
lineages.” What does clonally most nearly mean?
* 7. Look up a definition for interspecific and contrast it to the word intraspecfic in the space below.
**An Allele is a different version of a gene. Ex. The gene for flower color in peas has 2 alleles. One allele
codes for white flowers and one allele codes for purple flowers.
8. How is it thought that most parthenogenic species originate? (Through what mechanism?) Make sure you
explain what this means.
9. What does this particular origin allow unisexual species that most asexually reproducing species would
lack?
Use box #1 to answer question #10 & 11.
10. Explain how Gynogenesis is different from Parthenogenesis.
11. Is there a difference in how closely related (genetically
speaking) the parent and offspring are in gynogenesis and
parthenogenesis. Explain your answer.
*12. Explain how/why mitochondrial genes can be used to trace back maternal lineage.
*13. How many copies of each chromosome are present in typical DIPLOID species at the beginning of
meiosis? Think # of chromatids for number of copies. Use the example of human cells to illustrate your point.
14. How many copies of each chromosome are present in most (possibly all) persistently unisexual vertebrates?
*15. What does somatic mean? How many chromosomes (general term) are in somatic cells?
16. List and describe the two common mechanisms of increasing chromosome number in unisexual species.
17. Color the picture below using 2 separate colors. Here each color represents the maternal or paternal copy
of a chromosome.
18. What is the diploid # of the cells in figure 2 (shown above)?
19. Besides ovulation of eggs carrying the somatic chromosome complement what else influences the
establishment prospects of an interspecific hybrid?
20. What is thought to be the “KEY Prerequisite” for ecological success of unisexual species?
*21. A. What does the Prefix ‘HETERO’ mean?
B. So when reading the statement “Maintaining a high degree of heterozygosity depends on how premiotic
bivalents form.” You could read the statement “Maintaining a high degree of
______________ness/variation depends on how premeiotic bivalents form.
*22. What typically happens at the beginning of Prophase 1?
23. What is the result of homologous chromosomes pairing up in Parthenogenic/unisexual species?
24. What mechanism has been shown to prevent some asexual species from loss of heterozygosity over time?
Explain how this differs from what typically happens in meiosis (contrast this mechanism to your answer in
#22)
25A. What is still unknown/unclear about this mechanism?
25B. In the last paragraph on page 84 what does ‘deleterious’ most nearly mean?
26. What is suggested about the spread of beneficial mutations?
*27. What does embryogenesis mean?
28. A. When do vertebrate oocytes typically stop maturation (in what stage of meiosis)?
B. What triggers continued maturation fo the cell?
29. We have discussed the fact that cytoplasm & cell parts are inherited maternally. What cell part do sperm
bring to Gynogenic lineages and why is this important?
30. Is it known how parthenogenic lizards get around this requirement? How might parthenogeic insects
provide a clue?
*31. A. What does ‘Elevation of ploid’ mean? Think where you have heard the term ploid before.
B. What does triploid mean?
32. Explain why presumed diploid ancestors of triploid species are thought to be no longer present.
33. Through thought of as ‘Evolutionary dead ends’ as previously mentioned, scientists estimate one unisexual
lineage of salamanders has persisted for how long? (Box.2)
*34. What does FACULTATIVE most nearly mean here?
35. In what groups have Faculatative parthenogenesis been documented?
36. Are the mechanisms of meiosis in facultative parthenogenic species and obligatory/persistently
parthenogenic species the same? Explain your answer.
*37. Why do you think the types of meiotic mechanisms found in facultative parthenogenetic species are not
found in obligatory/persistently parthenogenic species?
38. Are there any known documented cases of facultative parthenogenesis in captive mammals? In captive
birds? Why is this thought to be?
39. What would you like to know/investigate about unisexual reproduction in vertebrates?
40. What questions do you have about the article?