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Dispersal
Active/Passive
the movement of an organism away from its point of origin
active involves locomotion by the organism itself
durring passive, the organism is transported by gravity, wind, water, or other organisms
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Jump Dispersal
the dispersal of a species across a geographic area that is not occupied by the species
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Waif Dispersal
successful long distance jump dispersal events
overall, pretty rare, but with 10-100 million species on the planet, a "one in a million chance" does occur
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Sweepstakes Routes
Geographic routes with low probability of successful dispersal
overall, pretty rare, but with 10-100 million species on the planet, a "one in a million chance" does occur
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Diffusion
the expansion of the range of a species along a discrete front
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Anemochores
organisms dispersed by wind
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Zoochores
organisms dispersed by other organisms
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Corridor
Geographic features that promote dispersal and colonization
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Filter
avenues of dispersal and colonization that are not equally favorable for all species
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Super Tramp
species that are particularly well suited to long distance dispersal and successful colonization
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Propagule
the stage in the life cycle (a plant seed for example) part of an organism (a piece of marram grass which can develop a new set of roots and grow into a full sized grass plant), or group of organisms (a male and female rabbit of matting age) that is required to establish a new reproducing population
EX) male/female (minimum requirement for pass on their genes)
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Stepping Stones
chains of closely distributed islands or discrete areas of similar habitat, such as mountains surrounded by low elevation deserts, that aid in the dispersal of some species
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Establishment
- Once you get to the island, you need to be able to
- “establish” yourself
Getting there isn’t good enough
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Evolution
Micro/Marco
Genetially controlled changes in physiology, anatomy, and behavior that occur to a clade over time.
Micro refers to evolution at the scale of the species.
Macro refers to evolutionary changes viewed at higher taxonomic units such as genera and families.
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Convergent Evolotion
the development of similar morphological or physiological traits in unrelated species living in geographically seperated regions that have similar environments
EX) Australia/Africa/U.S. rats
- similar phenotype, completely different genotype
- fill similar niche
- similar phenotype due to similar niche in the similar environment
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Parallel Evolution
occurs when geographically isolated populations derived from the same ancestor evolve into morphologically and physiologically similar descendent species
EX) gecho in carribean
- species from a common ancestor, and they fill same niches.
- these evolve into different species, and jump dispersal since they cant have the same niche in the same environment
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Genetic Drift
stochastic changes in the genetic composition of a population that occur over time as new genes arice via mutation and other genes are lost through change variations
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Natural Selection
the process by which the genes for genetically controlled traits become more common in a poulation over time because individuals with those traits are reproductively more successful than other individuals.
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Phyletic Gradualism
a slow and gradual process of evolution during which new taits arise by mutations and traits which infer greater reproductive success are selected for and eventually become dominant over many generations
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Punctuated Equilibria
- a model of evolution in which new genotypes and species arise as small isolated populations or populations at the edges of the main species population.
- These small populations increase and bery rapidly become dominant when environmental changes cuase them to be better adapted to new environment conditions
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Allopatric Speciation
the formation of new species by geographic isolation
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Sympatric Speciation
the development of new species within the same geographic area as the parent species
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Founder Principle
the idea that populations founded by a very small number of indivuduals generaly contain a small subset of the total genetic variability of the main population and are prone to allopatric speciation
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Adaptive Radiation
- the development of many species from a single founding species.
- the new species evolve to occupy the different range of habitats and use the different resources that are present in the region in which adaptive radiation occurs.
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Vicariance Event
geologic events or environmental changes that divide the ranges of species into geographically isolated distributions.
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Genotypic Variations
nonobservable differnces in the genes between different species or members of the same species.
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Phenotypic Variation
observable differences in the physiology, anatomy, or behavior of different species or individuals of the same species
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Extinction
the loss of all individuals of a species, genus, family, or order.
may be local or global
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Trophic Cascades
occurs when the loss of an important prey species causes further evosystem disruptions and extinctions because of the loss of food for higher predators
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Red Queed Hypotheses
states that because all of a species' competitors are continually evolving and becoming more competitive, if a species cannot evolve quickly enough to keep pace with the evolution of competing species, it will become extinct
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Great American Exchange
the movement of terrestrial fauna that occurred following the establishment of the Isthmus of Panama
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Cosmopolitan
having a global geographic distribution
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Provincialialism
having only a few geographic distributions
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Biographic Line
a geographic boundary dividing beographic regions
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Biographic Realm
supercontinental areas taht contaim similar flora and fauna
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Biographic Region
continental and superconitnental areas that contain similar flora and fauna
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Biographic Province
subcontinental areas that contain similar flora and fauna
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Charles Darwin
Didn’t believe in evo before the beagle
Invited onto the beagle as the ships naturalist, but also to hang with the capt
Jumping from one port to the next, collecting data
Gets to the Galapagos
Finds different this and that on the same islands, and on different this and that on different islands
Darwin didn’t write down where he found the finches at lol
GEOGRAPHY mattered!!!!
Became a geographer eventually
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Alfred Wallace
Alfred Wallace was the first to see variation
When collecting his insects, he would get more than one.
Did it to sell for money, not cause he didn’t believed in species topology;
Darwin got only one cause of species topology (collect one, collect all)
Starts to believe in evolution
Sends his idea about evolution to Darwin;
Darwin was like, WTF!! hahahahaha
Some loser just selling crap for money could steal his thunder
Each present a paper
Darwin released his book the next year, while Wallace was still in Malaysia hahahaha sucker!!!!!
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Transition Zone Between Definitions and Essay Questions
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Define Evolution. What is fitness and natural selection? Compare and Contrast macro and micro evolution with examples.
evolution is genetially controlled changes in physiology, anatomy, and behavior that occur to a clade over time
clade is the lineage of different related species that arise from a common ancestor
Micro refers to evolution at the scale of the species
Macro refers to evolutionary changes viewed at higher taxonomic units such as genera and families
natural selection is the process by which the genes for genetically controlled traits become more common in a poulation over time because individuals with those traits are reproductively more successful than other individuals
- micro evolution EX)
- mosquitoes evolving resistance to DDT
- whiteflies evolving resistance to pesticides
- gonorrheal bacteria strains evolving resistance to penicillin
- HIV strains evolving resistance to antiviral medicines
macro evolution EX)
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What genetic effects lead to speciation?
Compare and Contrast allopatric and sympatric speciation
Genetic effects that lead to speciation include: Variation
- Variation comes from mutation
- Comes from parents
- allopatric speciation is the formation of new species by geographic isolation
sympatric speciation is the development of new species within the same geographic area as the parent species
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What are the major causes of extinction?
What are some types of extinction?
What are species rick factors?
The top three man made reasons for extinction include habitat loss, exotic species, and explotation.
Some types of extinction include deforestation and isolation/fragmentation
Deforestation
Whatever habitat you had there is gone
Less biodiversity
Fewer resources
More competition
Fewer large animals (trophic pyramid)
Insects the same, but after that, forget it
Huge reduction as you go down in size
Isolation
Areas in between areas of forest become like barriers causing no jump dispersal
This process is called fragmentation
Large forest being broken up into smaller fragments
Species Risk Factors (if you are this, you are more at risk to go extinct)
More specialized
Low genetic variability
Cant adapt to changes
Size
Need more food if you are bigger
Carnivore even worse cause there are bunch of animals below you than just a herbivore that eats the very botton of the trophic pyramid (plants)
Low reproduction cycle
If you only have offspring once every 5 years, you will be more at risk of going extinct than if you have 100 offspring every year
Abiotic Factors
Changes that are non living
Storms
Climate change
Fires
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Compare and contrast active and passive dispersal.
Include examples of mechanisms used and range expansion
- active involves locomotion by the organism itself.
- during passive, the organism is transported by gravity, wind, water, or other organisms
a great example of range expansion is cheat grass. cheat grass was accidentily introduced into NorthWestern America (started off in only the state of Washington), and through a series of jump dispersal, aided by passive dispersal of its seeds in feed and with live stock, it spread throughout the west (Washington, Oregon, Idaho, California, Nevada, Utah)
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Compare and contrast a corridor and a filter dispersal route.
What types of barriers to dispersal create filters?
a corridor is a Geographic features that promote dispersal and colonization
a filter is an avenue of dispersal and colonization that is not equally favorable for all species
Barrirs leading to filters.......
Can be physical or ‘psychological’
Psychological meaning:
Barrier a species can pass, but choses not to
EX) Small rodent will go the long way that is covered than go the fast way that is not
Corridor
A potential dispersal route that is not limited in any way
Everything in ‘zone a’ can get to ‘zone b’
Central America is NOT a corridor because some make it and some don’t; to be a corridor, all would have to be able to make it
today, geographers try to create a corridor for animals; very hard to do
need the right habitat
need lots of space
need multiple life cycles
one makes it this far, the next generation makes it further, etc
in the real world, there are NO corridors; instead, we have FILTERS; filtering out some animals
EX) island jumping
only way to get pass the filter of water is jump dispersal (the water is the filter, filtering it, to where some animals make it and some dont)
in some cases, plants use wind/birds to carry seeds
how do animals get there?
Swim
frogs catch rides as well
Duck lands in a pond
Pick up water, in the water is eggs
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What is required for success of dispersal after arrival?
What aspects are involved?
Odds are way against you due to new habitat
As you get further away from home, the number of those that make it drop FAST; meaning less biodiversity
Success upon arrival is so low that some routes are called 'sweepstakes routes"; meaning the chance of success is the same chance as somone winning the lottery or sweepstakes
The best way for a species to survive include being eury everything...euryhaline (saline), euryphagous (food), eurythermic (temp)...the more wide their range is, the better they will be able to adapt into a new environment
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What weedy characteristics make invasive species good at dispersal and establishment?
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How are realms, regions, lines, provinces identified and classified in biogeography?
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Compare and contrast endemism and cosmopolitanism
Which is more uncommon and why?
Endeminism is when a species, genera, or family is restricted to one or a few geographic regions
Cosmopolitanism is when a species, genera, or family has a global geographic distribution
In general, endemism is the common state for land plants and animals, while true cosmopolitians are rare.
cosmos rare because:
- eury in every category is very hard to do
- generalist able to survive in many areas
- good competitors and colonizers
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DISPERSAL
Figure 8.4
- top one:
- seed being dispersed by wind
- most seeds (500) are being dispersed close to parent
- number of seeds droped drops dramatically from about 10-50 meters
- once hit 50 meters, only about 40 seeds are being dropped, and once you hit 100 meters, only about 10 are being dropped
- bottom one:
- seed being dispersed by an animal
- about 80% of seeds are being dropped at 0-20 meters
- number drops dramatically from 20-50 meters
- only about 10 percents of seeds are droped past 50 meters, and only about 5 percent of seeds are dropped past 100 meters
Outcome:
difference isn’t really huge
most are falling near parent
doesn’t really change whether it is caused by wind or animals
hard for jay to fly a long way while carrying a nut
also, the further you get from home, the more the environment is going to change
TIPPING POINT is around 50 meters for both with only a tiny portion transported more than 100 meters away
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JUMP DISPERSAL AND RANGE EXPANSION
Figure 8.8
House Finch and Jump Dispersal
Introduced to Long Island
spread from Massachusetts to North Carolina
slowly diffusing over time through jump dispersal and the establishment of small disjunct (distinct) populations in advance of the main diffusion front
home still the same place, just migrating out further
Don’t go from one place to one right next to it; it 'jumps' to a further one away
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ADAPTATIONS
Figure 9.1
Yarrow Plants
they grow from a near sea level (0 meters lol) to elvations of over 3600 meters!!!!!
- tall in the lowlands (70cm)
- small in the highlands (20cm)
low stature allows them to survive at high elevations because it keeps the flowering heads protected from frostbite and closer to the warm ground surface
height decreasing with elevation
drop in elevation causes higher height, just not as tall as original
What causes the difference? Is it the genotype or phenotype (the environment)?
Only one way to find out:
Plant the seeds somewhere else
If you move it to the west or east and it’s the same size, genotype (moved it to a different geographic location and nothing changed...must be the genotype)
If you move it to the west or east and it changes, phenotype (environment) (could still be genotype as well, but you do know now that the environment has the ability to change it as well ;)
Answer in this case is a little bit of both; big chunk was pheno though; when they transported the small ones to lower elevation, they stayed around 20 cm
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ADAPTATIONS
Figure 9.7
Adaptive Radiation
def of AR --> the development of many species from a common ancestor to fill all of the available niches in the colonized region
utilize different niches to take advantage of different foods
all evolved from same ancestor
in order to survive, they evolved different niches
fish eat on separate food
different mouth mutation
- small mouth for zooplankton
- sharp mouth for picking invertebrates off vegetation
birds eat on different flowers
different beak mutation
- small, thick beak for eating fruit and seeds
- sharp beaks for prying bark apart to find insects
- long slender beak to obtain nectar
if optimum range becomes bad range:
opt range def --> Range where most of the species stay dut to some geographic limiting factor
Some natural phenomena changes the optimum range into an unlivable range
You either get extinction, move to the sides, or two completely different optimum ranges
Showed pic in class, but not in book...WTF!!!!!
Darwin’s finches:
Short beak lives on this island
Med beak lives on this island
Large beak lives on this island
All three can spread out on the entire island, but dont so neither go extinct
Short/med beak lives on this island
All beaks lives on this island
These two scenarios break up the land on their islands
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