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population increase under idealized conditions
exponential population growth
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exponential growth at its max
intrinsic rate of increase
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dN/dt=r(max)N
equation of exponential population growth
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what does exponential population growth result in
J-shaped curve
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What does the J-shaped curve of exponential growth characterize?
- rebounding populations
- elephants @cougar nat. park
- deer
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exponential growth + carry capacity=
logistic growth
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model type where the per capita rate of increase declines as K is reached
logistic growth model
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max population size the environment can support
carrying capacity
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how to construct the logistic model
- exponential model
- +expression that reduces per capita rate of increase
- as N increases
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whats going on when the logistic growth model overshoots
- environment is pushing back
- population starts increasing @ a decreasing rate
- at inflection point N=K
- K=carrying capacity
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difference between exponential growth graph vs. logistic growth graph
- * exponential: no K, dN/dt=N
- *logistic growth: sigmoid curve, (K-N)/K
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what happens when K is approached or overshot
oscillation
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3 graphs for logistic models
- paramecium-typical
- daphnia-oscillation
- sparrow-fluctuations
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pluses and minuses of the logistic model
- useful for estimating possible growth
- model fits few real populations
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type of species for logistic model that's there for the long haul
type of density sensitivity
- K species
- density-dependent selection
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type of species for logistic model that's prolific and not good competitors
type of density sensitivity
- r species
- density-independent selection
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list 3 things related to the exponential growth model
- r, birth rate - death rate
- intrinsic rate of increase
- J-shaped curve
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list 5 things related to logistic growth model
- K, carrying capacity
- K-N/K
- sigmoid curve
- inflection point
- overshoot, oscillation
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concepts of K- and r- selection are somewhat controversial, bc may be oversimplifications
r-K continuum
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population where birth rate and death rate do not change with population density
density-independent populations
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population where birth rates and death rates rise w/population density
density-dependent population
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regulates population growth
negative feedback
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6 reasons/factors for density dependent population regulation
- competition for resources
- territoriality
- health
- predation
- toxic wastes
- intrinsic factors
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in crowded populations, increasing population density intensifies intraspecific competition for resources
competition or resources
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subset of homerange
place where animals will defend
territoriality
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3 examples of health influences in dense populations
- Spanish Flu
- Airline attendants
- Chronic Wasting Disease
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explain DD populations and predation feeding preferentially
and example
- Predator shift:
- as a prey population builds up, predators may feed preferentially on that species
- fly fishers-trout
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example of toxic waste accumulation contributing to DD regulation of population size
yeast levels top at 13% for wine because it cannot tolerate higher ethanol environment
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internal,physiological factors that appear to regulate population size
intrinsic factors
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focuses on complex interactions between biotic and abiotic factors that cause variation in pop size
population dynamics
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example of long-term population study to prove that populations of large mammals are stable over time
isle royale moose
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groups of populations linked by immigration and emigration
metapopulations
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where are extreme fluctuations in pop size more common
invertebrates
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two factors that result in greater stability in populations
- high immigration
- high survival
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graph representing island w/less migration vs island w/large migration
ecological vaccum- if island pop is decreased it will get filled by mainland birds=pop stability
island further away-takes a long time to rebound
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these are influence by complex interactions between biotic and abiotic factors
boom-and-bust cycles
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about when did the human population grow exponentially?
1650
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when did the human population growth rate start to slow?
- 40 years ago
- increasing at a decreasing rate
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who predicted serious problems if human don't maintain pop stability
- Paul Elich
- "Population bomb"
- ZPG
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ZPG
zero population growth
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2 ways to achieve balance, demographic transistion
- ZPG=
- high birth-high death
- low birth-high death
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moves regional patterns of pop change from 1st state toward 2nd state
demographic transition
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2 structures that predicts growth trends for present and future in a country
- population pyrimids
- age and sex
- how many @ age class
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what greatly varies among developed and developing countries but does not capture the wide range of human condition
- infant mortality
- lie expectancy
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describes how many humans the biosphere can support
global carrying capacity
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how many planets would it take for everyone on earth to live like americans?
4 and 1/2
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external physiological factors that appear to regulate population size
extrinsic factors
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two uses for population pyramids
- post reproductive-what's happened in the past, make futures plans ie incentives to have children
- pre reproductive
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concept that summarizes the use of land and water needed to sustain people of a nation/ how close we are to the carrying capacity of the earth
ecological footprint
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what are we doing by importing goods?
exporting pollution and deforestation
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step up from population
community
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an assemblage of populations of various species living close enough for potential interaction
biological community
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5 community interactions
- competition
- predation
- herbivory
- symbiosis
- disease
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interspecific interaction - -
competition
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4 interspecific interaction +-
- predation
- herbivory
- parasitism
- disease
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2 interspecific interaction ++
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one species benefits from the interaction, the other is unaffected by it
commensalism
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example of parasitism in great lakes
- lamprey eels,
- from ocean, used to bigger fish
- in great lakes is killing fish because they are smaller
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example of disease
- ebola virus
- from africe, finding it by international airports
- kills quickly, bleed from orfices
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two species competing for the same limiting resources cannot coexist in the same place
- competitive exclusion principle
- Gause's hypothesis
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total of species use of biotic and abiotic resources
species ecological niche
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father of modern ecology that studies ecological niches
Eugene Odum
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where the species lives, eats, lives on
habitat address of organism
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what the species does, what prey it feeds on, size
niche-profession
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the circle for a species niche, what it would like to do
fundamental niche
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the species niche circle plus competitions niches
realized niche
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differentiation of ecological niches, enabling similar species to coexist in a community
resource partitioning
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way to express why animals are distributed in a close community, like a tree
ghost of competition past
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person who studied warblers location on a conifer
MacArthur
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tendency for characteristics to be more divergent in sympatric pops of 2 species than allopatric pops of same 2 species
character displacement
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alone species
independent
allopatric
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same species overlapping
animals that are the same but feed on different food
sympatric
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example of sympatric vs allopatric
- Galapagos finches beak sizes
- 2 on 1 island-different sized beaks
- 2 on separate islands-same beak sizes
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interaction where one species kills and eats the other
predation
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5 predator adaptations for competing in an ecological niche
- claws
- teeth
- fangs
- stingers
- poison
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6 defensive adaptations prey have developed for surviving in an ecological niche
- hiding
- fleeing
- self-defense
- alarm calls
- morphological
- physiological
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coloration or camouflage that makes prey difficult to spot
cryptic coloration
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animals with effective chemical defense often exhibit bright warning coloration
aposematic coloration
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frogs that were use for neurotoxin, to kill
and for licking
poison arrow frogs
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what did Dr. Standora grab onto that was clearly aposematic
fire coral
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a palatable or harmless species mimics an unpalatable or harmful model
Batesian mimicry
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two or more unpalatable species that resemble each other
Mullerian mimicry
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plant mechanical and chemical defenses and adaptations
herbivory
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types of plant mechanical defenses, herbivory
thorns
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location plants have bad tasting chemicals
new growth areas
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plants that eat bugs
carnivorous plants
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2 types of carnivorous plants
- active-venus fly trap
- passive-pitcher plant
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biological magnification that happens with herbivory
- cadmium in larvae prey
- =less healthy plant shoots
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what 2 types of community interactions exerts substantial influence on populations and the structure of communities
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animal that has eggs laid on it
- parasitoid
- wasp lays eggs on caterpillars,
- immediate food source
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how have caterpillar evolved to avoid being a parasitoid
mimicry with tufts of hair that look like eggs
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3 types of pathogens, disease-causing agents
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disease that has killed 100,000's of birds in the last 5 years
west nile virus
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