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BI107 Exam 3


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a group of individuals from the same species that live in the same area at the same time
the study of factors that determine the size and structure of populations through time
individuals enter a population by moving from another population
individuals leave a population and join another population
the average time between a mother's first offspring and her daughter's first offspring
life table
summarizes the probability that an idividual will survive and reproduce in any given year
is the proportion of offspring produced that survive, on average, to a particular age.
a group of the same age that can be followed through time
What is a Type I Survivorship curve and give an example of an organism who has it?
Type I: High Survivorship until old age where the Survivorship decreases. An example would be elephants or humans.
What is a Type II Survivorship curve and give an example of an organism who has it?
Type II: Steady decrease in survivorship as age increases. An example would be birds or other small organisms
What is a Type III Survivorship curve and give an example of an organism who has it?
Type III: Low Survivorship in early years followed by high survivorship, an example would be an oak tree
The number of female offspring produced be each female in the population
age-specific fecundity
the average number of female offspring produced by a female in an age class
age class
group of individuals of a specific age
Why is there variation in fecundity and survivorship?
Every individual has a restricted amount of energy and resources at its disposal causing a difference
Organisms with high fecundity tend to...
grow quickly, reach sexual maturity at a young age, and produce mand small eggs or seeds
Organisms with high survivorship tend to...
grow slowly and invest resources in traits that reduce damage from enemies and increase their own ability to compete for water, sunlight, or food
life history
how an individual allocates resources to growth, reproduction, and activities or structires that are related to survival
delta N
change in number of individuals in a population
population growth
delta N/delta t
per-capita rate of increase
(r) the difference between birth rate and death rate
intrinsic rate of increase
(r max) when conditions are optimal-- birth rates are as high as possible and death rates are as low as possible
density independent
increases in size of population do not affect r
density dependent
increases or decreases in the size of population affect r
carrying capacity
(k) as maximum number of individuals in a population that can be supported in a parituclar habitat over a sustained period of time
logistic growth equation
delta N/delta t = (r max)(N)((K-N)/K)
logistic population growth
changes in growth rate that occur as a function of population size, it is density dependent
what two general factors change population sizes?
density dependent
density independent
density independent factors
change bith rates and deat rates irrespective of the number of individuals in the population. They are triggered by abiotic factors
density dependent factors
usually biotic changes in intensity as a function of population size
population dynamics
changes in population through time
What is the longest running experiment in the history of Biological science?
the Park Grass study in Rothamsted, UK
population cycles
regular fluctuations in the size that some animal populations exhibt
what is an example of an population cycle
red grouse (cycle do to transfer of worm when populations started to get crowded)
age structure
the proportion of individuals that are at each possible age
a population of populations
zero population growth (ZPG)
when fertility = replacement rate for a generation
Migration from nearby populations creates a...
balance between extinction and recolonization
population viability analysis (PVA)
a model that estimates the likelihood that a population will avoid extinction for a given time period.
What value (%) of a PVA considers a population viable
95% of surviving for 100 years
What is the defining feature of exponential growth?
the growth rate is constant
what four factors define population growth?
death rate, birth rate, immigration, emmigration
benefit from the association but have no impact on the other species
coevolutionary arms race
predator and prey influence each others evolution. Species constantly improving causing other species to improve
intraspecific competition
compeition within the same species, major cause of density dependent growth
interspecific competition
competition between different species
set of habitat requirements, the range of resources that the species is able to use or the range of conditions it can tolerate
When does interspecific competition occur?
When the niches of two species overlap
competitive exclusion principle
not possilbe for species with the same niche to coexist
asymmetric competition
one species suffers a much greater fitness decline than the other species
symmetric competition
each species experiences a roughly equal decrease in fitness
fundamental niche
niche without predators
realized niche
niche when competition occurs
niche differentiaion
competing species evolve traits that allow them to exploit different resources or live in different areas
What are the 6 mechanisms of competition?
consumptive, preemptive, overgrowth, chemical, territorial, encounter
Consumptive competition
two species consume the same resources. (Tree growing in the same area competiting for water and nutrients)
Preemptive competition
one species makes space unavailable to others. (Barncles in tidal zone)
Overgrowth competition
one organism grows over another. (Fern overgrowing individuals shading them)
Chemical compeition
one species produces toxins that negatively affect another. (saliva shurbs)
territorial competition
mobile organisms protect a feeding or breeding territory. (Grizzly bears)
encounter competition
organisms interfere directly for access to specific resources (hyena and vulture fight over kill)
What is a common experimental strategy when dealing with competition?
removing a competitor
standing or constitutive defenses
defences that are always present
What are three constitutive defenses?
schooling, camouflage, and weaponry
when one species closely resemble another species
Mullerian mimicry
when harmful prey resemble each other (posionous toads)
Batesian mimicry
harmless species look like harmful prey
inducible defenses
defensive traits that are produced only in response to presence of a predator.
a study of studies
top-down control
herbivore populatios are limited by predation or disease
plants are poor food source in terms of the nutrients they provide for herbivores
plant defense
plants denfend themselves effectively enough to limith herbivory.
Not all interaction require individuals from differents species to be...
nice to each other (altruistic)
climax community
the stable final stage after communities develop by passing through a series of predictable stages dictated by extensive interactions among species
keystone species
a species with much greater impact than its abundance would suggest.
any event that removes some individuals or biomass from a commmunity
What are some examples of disturbances?
forest fires, hurricanes, floods, fall of large canopy tree, disease epidemcis
how is the impact of a disturbance determined?
1)type of disturbance
2)frequency of disturbance
3)the severity of the disturbance
disturbance regime
a characteristic type of disturbance with a predictable freequency and severity
what are the two approaches to determining disturbance regimes?
(1) using short term analysis to predict long term patterns
(2) reconstructing history of a particular site
recovery that follows a disturbance
primary succession
occurs when a disturbance removes the soil and its organisms as well as organisms that live above surface
secondary succession
occurs when a disturbance removes some or all of the organisms from an area but leaves the soil intact
successional pathway
specific sequence of species that appears over time
What three effects to species have during succession
facilitation, tolerance, inhibtion
promotes growth of other species
neutral to growth of other species
prevents growth of other species
pionerring species
first species that arrive after a disturbance, they usually have a high dispersal rate
species richness
is a simaple count of how many species are present
species diversity
variety of species in a community
Net primary productivity (NPP)
is the amount of photosynthesis per unit are per year that ends up in biomass
preventing a disturbance
recovery from a disturbance
as species richness increases production...
What four components are linked by the flow of energy?
abiotic enviorment, primary producers, consumers, and decomposers
primary producer
any organism that can sythesize its own food (autotroph).
eat other organisms
or detritivores are consumers that obtain energy by feeding on the dead remains of other organisms or waste products.
What place has the highes NPP?
the ocean
Why is the ocean produce 25% of the world NPP?
it takes up such a large area
primary consumer
grazing food web
the collection of animals that eat plants and animals that eat them
secondary consumers
consumers that eat herbivores
decomposer food web
composed of species that eat the dead remains of organisms
dead animals and dead tissues that accumulate and create plant litter
trophic level
organisms that obtain their energy from the same type of source are said to pccupy the same trophic level
food chain
connects trophic lebels in a particular ecosystem
food webs
shows what each organism eats in a particular ecosystem (more complex than food chain).
Why are is the equator more diverse than the poles?
parasite-predator, high productiviy, stability
gross photosynthetic effciency
efficiency with which plants use the total amount of energy available to them
secondary production
production of new tissue by primary consumers
Where does most evaporation occur during the global water cycle?
over the ocean
What are some effects on the water cycle due to land clearing?
increase run off, decrease rainfall by decreasing terrestial evaporation
Why can't carbon be stored sufficently in the ocean?
Low rate of exchange
Why are fossil fuels so bad?
The carbon produced by them can't be getting rid of fast enough creating a green house effect
What are three human effects on the Nitrogen cycle?
industrial fertilizers, crop cultivation using N2 fixers, fossil fuel combustion
In what form does nitrogen have to be in to be used by plants?
NO3 or NH4
What are two main areas of human impact?
Global warming, and productivity increase
Why is productivity increase bad?
decreases the species richness and can cause increase in eutrophication
the conversion of a lake to a highly productive ecosystem with rapid decomposition, low oxygen levels, and rapid decomposing organic matter
What is most of the NPP used for in an ecosystem?
respiration by primary consumers
all distinctive populations and species living today
genetic diversity
diversity in a parituclar species (allele diversity)
ecosystem diversity
variety of ecosystems in a particular region
direct benefits of biodiversity
any benefit from when a plant is cultivated
indirect benefit of biodiversity
anything beyond the direct use of a species
ecosystem services
processes that increase the quality of the abiotic enviorment
Taxon-specific survey
estimation of a specific type of organism such as insect living today
All-Taxon survey
estimation of all species in a particular ecosystem
location of largest all-taxon survey
The Great Smokey Mountains National Park
endemic species
taxa that are found nwhere else or a high proportion of endangered species
What happened on Easter Island?
resources were overexploited making the island inhabital for organisms
invasive species
exotic species that are introduced to a new area
habitat destruction
destruction of a habitat by humans
habitat fragmentation
fragmenting large areas of natural habitats into small isolated fragments
What are three problems that can occur when there is an invasive species?
competition, disease, predation
domino effect
endangering one species causes another species to go endangered
planned use of resources at a rate only as fast as the rate at which they are produced
Nongovernmental Organization
What are the two conservation strategies?
in situ, ex situ
in situ
protected areas
ex situ
zoos, aquaria, and botanical gardens
sustainable development
economic progress for local communities
What does a GAP analysis do?
compares the current distribution of species with the locations of preserved habitats

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