ANALYZING RADIATION IN HAWAIIAN DROSOPHILA
Name: _________________________
Background
The Hawaiian islands are located far away, near the
middle of the Pacific Ocean, 4,000 km (2,500 miles)
from the nearest continent. The Hawaiin islands are
rather young, with islands ranging from 0.5 to 10 million
years of age.
As you have learned, the Hawaiin islands are volcanic
in origin. J. Tuzo Wilson’s “Hotspot Theory”, that as the
pacific plate is moving in a northwesterly direction, at a
rate of 10 cm/year, an underlying hotspot regularly
erupts forming new islands, is well supported by the
fact that the islands increase in age and are lower in
elevation as one moves through the island chain to the
northwest.
In the following activity, you will come to a deeper understanding of the speciation and
adaptive radiation events that have occurred on these islands, and the diversity that
resulted from these processes. More specifically, you will learn a little bit about the
evolution of over 100 distinct species of Drosophila fruit fly species inhabiting the
Hawaiian islands.
The following activity was developed from the information and activity presented in the
National Academy of Sciences. (2004). Evolution in Hawaii: A Supplement to Teaching
About Evolution and the Nature of Science, Steve Olson. Washington, D.C. The
National Academies Press – www.nap.edu/catalog/10865.html
Procedure & Questions
Pre-Lab Questions
Read the Student Background Reading for help in answering the following questions.
1. What characteristics of the Hawaiian islands have been important to the adaptive
radiation of the Drosophila fruit flies? Explain how each characteristic you identify is
specifically important in the radiation.
2. Sketch two representative polytene chromosomes demonstrating in inversion in the
second relative to the first.
3. Contrast ‘homologous’ and ‘analogous’ structures as discussed in your textbook
beginning on page 493.
4. Based on your knowledge of homology, can the inversion patterns in the polytene
chromosomes of drosophila be used to determine possible evolutionary relationships
between currently living species? Explain.
Activity Questions
1. Given the following table of 11 possible inversions in 13 species of Drosophila fruit
flies, construct a cladogram or phyogenetic tree suggesting the evolutionary
relationship between the four species identified with an astrix. In your cladogram,
identify the shared primitive character as well as the location of each of the derived
inversions along the appropriate lineage (see page 498-9 for help).
Species
Ch X
D. heteroneura*
D silvestris
D. planitibia
D. differens
D. hanaulae*
D. obscuripes
D. hemipeza
D. oahuensis
D. substenoptera*
D. primaeva*
D. ornata
D. setosifrons
D. setosimenturn
ijkopqrst
ijkopqrst
ijkopqrst
ijkopqrst
ijkopq-st
ijkopq-sijkopq-st
ijkopq-st
ijkopq-si-ko ----i-ko ----ijko ----i-ko -----
Ch #3 Ch #4 Island
d
d
d
d
d
d
d
d
d
d
-
b
b
b
b
b
b
b
b
b
b
b
b
b
Hawaii
Hawaii
Maui
Molokai
Maui
Maui
Oahu
Oahu
Oahu
Kauai
Kauai
Hawaii
Hawaii
Cladogram
2. Based on your knowledge of the ages of the different Hawaiian islands, where do
younger species tend to evolve, older or younger islands? Explain.
3. Next, complete the narrative or story detailing the timing, movement, inversion
history, and evolution of the four Drosophila in your cladogram.
About four million years ago on the island of ____________ there lived an
interbreeding population of picture-winged drosophila fruit flies. Every member of
this population had the four chromosomal inversions __, __, __, and __. Then, …
Extention Questions
1. Based on the information in the table, where could the species D. setosimenturn be
added to your evolutionary tree? Explain.
2. How would your narrative change to incorporate D. setosimenturn?
3. Based on the information in the table, where could the species D. silvestris be added
to your evolutionary tree? Explain.
Using information on more than 200 inversions from over 100 drosophila species in the
Hawaiian islands, Hampton Carson suggested the following radiation of the picturewinged Drosophila. Using his image fill out the following table and then answer the
remaining questions (The numbers in bold in the table are the number of species
currently occupying each island. The example shows Oahu was the probable recipient
of 5 species from Kauai, while Kauai received 0 species from Hawaii.)
Recipient Island
Kauai
Kauai
Donor
Island
Oahu
12
Oahu
Maui
Complex
Hawaii
Maui
Complex
Hawaii
5
29
40
0
26
5. Is there a correlation between the age of the island and the number of species?
Explain.
6. Are younger islands more likely recipients or donors?
support your answer. Why does this make sense?
Give a few examples to
7. Finally, read the article on incipient speciation in Drosophila silvestris by Carson and
Bryant, and explain how data other than chromosomal inversions have been
important in this study.
Species
D. setosimenturn
D. ochrobasis
D. adiastola
D. hamifera
D. toxochaeta
D. touchardia
D. ornate
D. primaeva
D. setosifrons
D. heteroneura
Ch X
ikouvwxym2
ikouvwxym2
ikouvwxy ikouvwxy ikouvwxy ikouvwxy ikou- -xy iko - - - - - - iko - - - - - - iko - - - - - - -
Ch #2
cd
cd
cd
cd
cd
cd
c----
Ch #3
fjkl
fjkl
fjk f-k fjk fjk -------------
Ch #4
bopqb2
bopqb2
bopq bopq bopq bopq bo- - b---b---b----
Ch #5 Island
f
Hawaii
f
Hawaii
f
Maui
f
Maui
f
Molokai
f
Oahu
Kauai
Kauai
Hawaii
Hawaii
Student Background Reading