BIOL 2251 Study Guide - Midterm Guide: Ecological Speciation, Alfred Wegener, Species Problem

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26 Aug 2017
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BIOL 2251
Opportunity 3 Review
Chapter 6 Dispersal and Immigration
ALFRED LOTHAR WEGENER (1880-1930)
o Plate tectonics
o Continental Drift
Explained why the same/similar species could be found in two separate,
sometimes far away, locations
There is Paleontological Evidence
The continents could possibly come together again
DONALD RUMSFELD
o Basiall stated that there is a lot that e do’t ko
30% of all animals are beetles
Insects take up about half of the species chart
We only allocate money and scientific effort into three groupings of eukaryotes, out of
many
Corixidae
o Taxonomy:
Insecta
Hemiptera
Genus: Corixidae
Species: punctata and affinis
o Hutchinson noticed two types in the pond:
C. punctata
Larger
C. affinis
o They coexist because they have different breeding seasons
Larger species breeds before the smaller species
Why do we have so many different types of species? (HUTCHINSON, 1959: Homage to
Santa Rosalia)
o 1. Natural Selection
o 2. Isolation post-dispersal or vicariance
o 3. Speciation events:
Allopatric
Sympatric
Competitive
o 4. Gause’s La AKA Copetitie Elusio Priiple
o 5. Lotka-Volterra Equations predator-prey relationships
e.g. increased predation = decreased prey
o 6. Food chain energy transfer
Increased smaller animals
Depending on plants
Increased primary consumers (most animals)
o 7. Character Displacement
The divergence of a feature of two similar species where their ranges
overlap so that each uses different resources.
When two species live in separate habitats they can have very similar
morphology; when they live in the same habitat their characteristics
diverge
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BIOL 2251
Opportunity 3 Review
Example: Finch Beak Depth beak depth changes when they inhabit the
same island but are similar on separate islands
o 8. Mosaic nature of the environment
Increased niche space
o 9. Stable Environment
Stable and more complex food webs
True or false: A complex trophic food web is more stable than a simple one.
o True
Three fundamental processes
o Extinction
o Dispersal
o Evolution
Dispersal
o Movement away from point of origin/birthplace
o Usually confined to one life-history stage
o Natural selection favors movement that is a modest distance away from the
birthplace. Why?
Modest movement away from origin:
1. Intraspecific competition
2. Sexual Reproduction not out of range
3. Energy Conservation
4. Gene flow to nearby populations
Modest eause the eiroetal paraeters hage too uh
otherwise, due to spatial autocorrelation
o 3 key events that lead to a successful dispersal:
Travel to a new area; requires morphological adaptations to make the
trip.
Withstand unfavorable conditions to make the trip.
Establish a viable population upon arrival.
o Jump Dispersal
Long distance dispersal that happens in a short time.
Example: Krakatau
Erupted in 1883, but by 1933 there were 271 plants species, 31
bird species, invertebrates.
This as ahieed  steppig stoe dispersal aross the islad
chain and jump dispersal from source lands of Java and Sumatra.
Ho a ou erif the speies juped?
Phylogeny (DNA)
Accounts for similar species inhabiting similar habitats in different
geographic areas.
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BIOL 2251
Opportunity 3 Review
o Dispersal V Diffusion
Jump Dispersal
Diffusion
-long distance
-few individuals
-whole populations
-similar species inhabiting similar
habitats in entirely different
geographic locations
-Gradually spreads distribution out
from argis of speies’ preious
range
-fast, one or couple rare events
-slow, over the course of
generations; multiple attempts
o 3 steps of Diffusion
1. Initial invasion
maybe requiring repeated events and subsequent adaptations
2. Once established, diffuses at exponential rates
3. Eventually slows when the species encounters physical, climatic, or
ecological barriers.
o Example of Diffusion:
Bubulcus ibis (cattle egret) is native to Africa. In the 1800s it diffused into
South America, and then into North America;
Austrailian Cane Toad: Introduced by humans; diffused then jumped
o Insects that can disperse at higher altitudes usually have small wings
o Active Dispersal:
Dispersal of an organism using its own power
Vagility
Can disperse a moderate/farther distance
o Passive Dispersal
Dispersal by being carried by another agent, like wind or water, or other
organisms
life stage that is dorat ad a surie eiroetal etrees ad
a go ak ito its life le after dora ad dispersal.
Pagility
Can disperse only a small distance, closer to their origin
o Phoresy: Animals transported by other animals
Ex: mussel larvae in fish host
o Exozoochory: Plants attach themselves to the outside of animals
o Endozoochory: Plant propagules (seeds) that travel inside an animal
o The Aidetal Grinnell (1922)
Instead of traveling their normal route to Mexico, some Monarch
butterflies ended up in Cuba. To this day, some still travel to Cuba. No
idea what caused this to happen maybe a storm but it was accidental
they ended up in Cuba.
o Corridors: Very similar habitats than either side; allows for dispersal
o Filter: Different habitat between two or more areas; restricts dispersal
E: Wallae’s Lie that auses a sharp faual gap ear Bali
o Sweepstakes: rare event
Ex: 15 iguana individuals got aught up i hurriae, a fe o the
lotter ad laded o a egetatio raft to a e islad ad ere ale to
thrive
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