Assignment 4 Speciation and Hybridization
1. Essay (4 points)
Determine whether each of the species described below is best defined as a species by the biological species concept, evolutionary lineage concept (including morphological traits) or ecological species concept. For each species, indicate which concept you think is most appropriate, and write a sentence or two to justify your answer.
A. A certain species of plant is found in only one locality near a hotel in an area that appears devoid of most other life. The soil near the hotel has been tested and contains heavy metals that would kill most plants. The plant appears to propagate by runners (asexual reproduction) and does not flower. The population is slowly increasing and covers more of the barren area each year.
B. Archaeopteryx is one of the first fossils found that showed both bird and reptilian features (such as both feathers and teeth). Archaeopteryx probably had a wingspan of about 1.5 feet and was about 1 foot long from beak to tail. It weighed 11 - 18 ounces. Only 8 or 9 fossils of Archaeopteryx have been found, and only 4 contain most of the skeleton.
2. Essay (3 points)
Write a short essay on whether the hybrid ladybug should be considered a new species and, if so, by what species concept. HINT: There are many things about the hybrid ladybug that you do not know. Your conclusion should be based on what you hypothesize about the hybrid (e. g. Does it interbreed? Does it occupy the same ecological niche?).
3. Fill-in-the-blanks (5 points)
Carefully examine the facts about contemporary Hawthorne and Maggot flies that are listed in the table below and on your work sheet. Indicate whether each biological characteristic will serve as a selective force for or against continued divergence of these two races (or neither).
A. Hawthorn and Apple maggot adult flies are morphologically undistinguishable to us and presumably to each other. ______
B. Fidelity to fruit type is strong and Hawthorn maggot flies in the laboratory prefer to lay in Hawthorn fruit and Apple maggot flies prefer to lay in apples. ______
C. Hawthorn and apple maggot flies can be distinguished genetically and there is evidence that the genetic divergence between them has increased. ______
D. Both types of maggots survive better in Hawthorn fruit, 52% of all maggot fly eggs survived in Hawthorn fruits and 27% of maggot fly eggs survived in apple fruits. ______
E. Apple maggots bear 70% fewer eggs that are parasitized by wasps than do hawthorn maggots, but caterpillars and weevils may also feed on the larger apple, reducing the quantity of food available to apple maggots. ______
4. True and False (2 points - 0.5 point each)
View the video on salamanders, and note why/how the California salamanders evolved into two major lines. Then answer the following questions by writing the words true or false in the blanks:
______Salamanders that migrated through the forests of California evolved a color pattern better adapted for camouflage after many generations.
______Salamanders that migrated through the Western part of California evolved a different color pattern for better camouflage in the non-forest environment.
______Hybrids between the two lines of salamanders are better adapted to their environment than either of the parent lines.
______The divergence of the salamanders into different color patterns over time supports Darwin's view of natural selection.
5. File upload (3 points)
Fill out the table below by measuring wing lengths in the photographs on the course website. Then use your screen-shot technique to capture an image of the table and submit it to WebAssign (do not submit a doc file, since it is difficult to grade in WebAssign).
Table 1:Wing measurements
Trials / AFRICAN (mm) / EUROPEAN (mm) / UNKNOWN (mm)#1
#2
#3
Average
Note: your measurements should be in millimeters.6. Fill-in-the-blank (1 point)
In the above table, the wing length of the "unknown" bee was more similar to the ______bees. (Fill in the blank with African or European.
7. Essay (3 points)
Examine the reference, beekeeper A, and beekeeper B graphs which compare the wing lengths of a sample of unknown workers to wing length of workers from known Africanized and European workers. A. Tell beekeeper A whether or not he should destroy his hive.B. Tell beekeeper B whether or not he should destroy his hive.C. Write an explanation for your decision.
8. Fill-in-the-blank (2 points)
Based on the results of mitotyping gel electrophoresis, indicate whether Hive A and Hive B have an African or Euorpean queen. (Write African or European in the blanks.)
The queen of Hive A is ______. The queen of Hive B is ______.
9. Multiple-choice (1 point)
Many female insects store sperm from matings in an organ known as a spermatophylax. In a hive of European honeybees, the queen will preferentially use sperm from Africanized drones when mated to both Africanized and European drones.
If Africanized drones introduced into an area containing European hives, how might this affect the future behavior of bees and what would mitotyping of the worker bees show?
The workers will be unusually aggressive and their mDNA will have two bands. The workers will be unusually aggressive and their mDNA will have a one band.
The workers will be docile and their mDNA will have two bands.
The workers will be docile and their mDNA will have 1 band.
None of these are correct.
10. Multiple-choice (1 point)
Africanized queens develop faster and are more likely to become queens should a hive lose its queen. Generally, the first queen to develop in this situation stings her sisters to death before they emerge from their puparia. Any sister queens emerging at the same time fight to the death for possession of the hive. The Africanized queens win more of these fights, killing any newly emerged European queens.
If both African and European queens emerge at the same time to replace a dead queen, what will probably be the behavior and wing length of worker bees in future generations?
The workers will be unusually aggressive and their wing lengths will be longer than average.
The workers will be unusually aggressive and their wing lengths will be shorter than average.
The workers will be docile and their wing lengths will be longer than average.
The workers will be docile and their wing lengths will be shorter than average.
None of these are correct.
11. Essay (3 points)
A beekeeper suspects that his hive has been Africanized due to increased defensiveness and other aggressive behavior by worker bees. He submits a large sample for testing. The morphological data indicate more overlap with Africanized characteristics than with European characteristics. However, DNA analysis of mitochondria yields no evidence of Africanization. Write a short essay indicating how you would advise the beekeeper.