BIOL 2100 Final questions
and answers
Topic 1 - answer
Biogeography - answer The study of the distribution of species on earth, on
both long and short time scales.
Historical Biogeography - answer Relates evolution and earth history in
explaining the distributions of organisms.
Typically based on phylogenetic work.
Continental movements are critical in determining the current distributions of
many species.
Vicariant events - answer involve the formation of a barrier that separates a
previously continuous range of distribution into two or more pieces.
Dispersal events - answer involve colonization of new habitat.
Vicariance and dispersal account for the presence of a species in multiple
locations - answer
Vicariance - answer change in the environment
Physical barrier arises within the range of a species
Example - reindeer (Northern Europe and Asia) and caribou (North America)
are a single species that was divided into separate populations by
submergence of Bering land bridge ~ 15,000 years ago
Dispersal - answer movement of species
,Individuals of a species cross an existing barrier and establish a separate
population
Example - seeds of coconut palm will float and are widely distributed by
ocean currents
"The parsimony principle" - answer Observable distributions may have more
than one plausible explanation
Favor the hypothesis that requires the smallest number
of unobserved events
Simplest explanation is not always the correct one, and hypotheses must
take new information into account
Example of Vicariance - answer Vicariant Weevil distribution in New Zealand.
The Cook straight was not present in ancient NZ and allowed some weevils to
become separated over time from the other weevils on the south island.
After the Cook straight formed these flightless weevils were separated.
Example of dispersal - answer Indo-Pacific Reef corals. The coral larvae are
actually mobile and can travel short distances before settling into a new
habitat. This lets them disperse throughout the ocean and expand yet they
are concentrated in into pacific area due to lack of large mobility of coral
larvae as well as they require certain temperature and ocean conditions to
survive
Key Features of Island Biogeography - answer 1. dispersal ability 6.
relictualism
2. size change 7. loss of defenses
3. loss of dispersal 8. impoverishment
4. endemism 9. archipelago speciation
5. disharmony 10. adaptive radiation
Ecological Biogeography - answer Involves a strong focus on the interactions
and factors that determine species distributions in modern ecosystems.
,Island biogeography provides testable predictions of the equilibrium number
of species on an island.
A biological island may be a physical island (i.e., land surrounded by water)
or may be an isolated habitat (e.g., a mountaintop).
The island biogeography model has stimulated extensive observational and
experimental work on species richness
Major Biogeographic Provinces - answer On a regional scale, the earth can be
divided into distinct biogeographic provinces based on climate and the
dominant communities.
Terrestrial biogeographic provinces are predominantly zonal (E-W in
orientation), reflecting average climate.
Oceanic biogeographic provinces also tend to be zonal, but as a result of the
dominant circulation patterns in the ocean.
New Zealand is in the Antarctic terrestrial biogeographic province - answer
Species diversity on islands determined by the interaction between new
colonization and extinction - answer
Rates of both colonization and extinction of species will depend on: - answer
Distance separating the island from the nearest continent.
Size of the island itself.
Island of Krakatau - answer -Massive volcanic eruption occurred from
Krakatau in 1883. It ended up destroying 2/3 of the islands and eradicated
life on the islands nearby like Rakata.
Because of the volcano destroying everything, recolonization studies were
done on the islands.
-Nine months after the eruption the first organism colonized Rakata and it
was a spider
-Rakata island has since been a natural laboratory for testing predictions of
the MacArthur Wilson theory of island biogeography
, -in 1896 there were 11 species of ferns and 15 species of flowering plants
-16 had been dispersed by wind and 8 by sea
-Recolonization of Rakata was greatly affected by how well plants were able
to disperse.
-early plant communities were dominated by grasses, 25 yrs later it was
bushes, and in the 1920s it was Neonauclea trees
some methods of dispersal - answer cyclones, wind, sea, carrying by birds,
sometimes seeds are even eaten by birds and shit back out onto an island.
As the years go on the number of species increases linearly during the time
during which recolonization is occurring - answer
MacArthur-Wilson Model - answer Review the two graphs
What is benefit of MacArthur wilson Model - answer allowed us to generate
falsifiable predictions
Predictions for MacArthur Wilson model - answer Prediction 1: the number of
species should increase with increasing island size.
Prediction 2: the number of species should decrease with increasing distance
of the island from the source pool
Prediction 3: the turnover of species should be considerable
Lesser Antilles - answer A large chain of islands in the Caribbean Sea
All share a similar climate
All are surrounded by deep water
Historically, they have never been connected to a mainland, that is, they
have always been islands although size may have varied over time
That means these are a great example of dispersal
and answers
Topic 1 - answer
Biogeography - answer The study of the distribution of species on earth, on
both long and short time scales.
Historical Biogeography - answer Relates evolution and earth history in
explaining the distributions of organisms.
Typically based on phylogenetic work.
Continental movements are critical in determining the current distributions of
many species.
Vicariant events - answer involve the formation of a barrier that separates a
previously continuous range of distribution into two or more pieces.
Dispersal events - answer involve colonization of new habitat.
Vicariance and dispersal account for the presence of a species in multiple
locations - answer
Vicariance - answer change in the environment
Physical barrier arises within the range of a species
Example - reindeer (Northern Europe and Asia) and caribou (North America)
are a single species that was divided into separate populations by
submergence of Bering land bridge ~ 15,000 years ago
Dispersal - answer movement of species
,Individuals of a species cross an existing barrier and establish a separate
population
Example - seeds of coconut palm will float and are widely distributed by
ocean currents
"The parsimony principle" - answer Observable distributions may have more
than one plausible explanation
Favor the hypothesis that requires the smallest number
of unobserved events
Simplest explanation is not always the correct one, and hypotheses must
take new information into account
Example of Vicariance - answer Vicariant Weevil distribution in New Zealand.
The Cook straight was not present in ancient NZ and allowed some weevils to
become separated over time from the other weevils on the south island.
After the Cook straight formed these flightless weevils were separated.
Example of dispersal - answer Indo-Pacific Reef corals. The coral larvae are
actually mobile and can travel short distances before settling into a new
habitat. This lets them disperse throughout the ocean and expand yet they
are concentrated in into pacific area due to lack of large mobility of coral
larvae as well as they require certain temperature and ocean conditions to
survive
Key Features of Island Biogeography - answer 1. dispersal ability 6.
relictualism
2. size change 7. loss of defenses
3. loss of dispersal 8. impoverishment
4. endemism 9. archipelago speciation
5. disharmony 10. adaptive radiation
Ecological Biogeography - answer Involves a strong focus on the interactions
and factors that determine species distributions in modern ecosystems.
,Island biogeography provides testable predictions of the equilibrium number
of species on an island.
A biological island may be a physical island (i.e., land surrounded by water)
or may be an isolated habitat (e.g., a mountaintop).
The island biogeography model has stimulated extensive observational and
experimental work on species richness
Major Biogeographic Provinces - answer On a regional scale, the earth can be
divided into distinct biogeographic provinces based on climate and the
dominant communities.
Terrestrial biogeographic provinces are predominantly zonal (E-W in
orientation), reflecting average climate.
Oceanic biogeographic provinces also tend to be zonal, but as a result of the
dominant circulation patterns in the ocean.
New Zealand is in the Antarctic terrestrial biogeographic province - answer
Species diversity on islands determined by the interaction between new
colonization and extinction - answer
Rates of both colonization and extinction of species will depend on: - answer
Distance separating the island from the nearest continent.
Size of the island itself.
Island of Krakatau - answer -Massive volcanic eruption occurred from
Krakatau in 1883. It ended up destroying 2/3 of the islands and eradicated
life on the islands nearby like Rakata.
Because of the volcano destroying everything, recolonization studies were
done on the islands.
-Nine months after the eruption the first organism colonized Rakata and it
was a spider
-Rakata island has since been a natural laboratory for testing predictions of
the MacArthur Wilson theory of island biogeography
, -in 1896 there were 11 species of ferns and 15 species of flowering plants
-16 had been dispersed by wind and 8 by sea
-Recolonization of Rakata was greatly affected by how well plants were able
to disperse.
-early plant communities were dominated by grasses, 25 yrs later it was
bushes, and in the 1920s it was Neonauclea trees
some methods of dispersal - answer cyclones, wind, sea, carrying by birds,
sometimes seeds are even eaten by birds and shit back out onto an island.
As the years go on the number of species increases linearly during the time
during which recolonization is occurring - answer
MacArthur-Wilson Model - answer Review the two graphs
What is benefit of MacArthur wilson Model - answer allowed us to generate
falsifiable predictions
Predictions for MacArthur Wilson model - answer Prediction 1: the number of
species should increase with increasing island size.
Prediction 2: the number of species should decrease with increasing distance
of the island from the source pool
Prediction 3: the turnover of species should be considerable
Lesser Antilles - answer A large chain of islands in the Caribbean Sea
All share a similar climate
All are surrounded by deep water
Historically, they have never been connected to a mainland, that is, they
have always been islands although size may have varied over time
That means these are a great example of dispersal
