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Biology 180 - Exam 4

Terms in this set (63)

metapopulation
a population of populations connected by migration
replacement rate
average fertility required for each woman to produce exactly enough offspring to replace her and her offspring's father
community
all species that interact in a certain area
commensalism
(+/0) one species benefits but the other is unaffected
competition
(-/-) individuals use the same resources - lower fitness for both
consumption
(+/-) one organism eats or absorbs nutrients from another
includes
-herbivory
-predation
-parasitism
mutualism
(+/+) both species interact in a way that confers fitness benefits to both
coevolution
a pattern of evolution where two species influence each others adaptations over time
coevolutionary arms race
repeating cycle of reciprocal adaptation
interspecific competition
individuals from different species use the same limiting resources
intraspecific competition
competition between members of the same species
-water, space, sunlight, food etc
niche
a range of resources that a species is able to use or the range of conditions it can tolerate
symmetric competition
a decrease in fitness due to niche overlap - both species are affected equally
asymmetric competition
occurs when one species suffers a greater fitness decline than other species
- usually depends on amount of overlap in niche
competitive exclusion principle
two species that occupy the same niche cannot coexist
fundamental niche
total theoretical range of environmental conditions that a species can tolerate
realized niche
portion of the fundamental niche that a species actually occupies, given limiting factors such as competition with other species
fitness trade off
inevitable compromises in adaptation
niche differentiation
evolutionary changes in resource use caused by competition over generations
- aka resource partitioning
character displacement
evolutionary change in traits that allows species to exploit different resources
- makes niche differentiation possible
herbivory
consumption of plant tissues
parasitism
a parasite consumes relatively small amounts of tissue or nutrients from another individual (the host)
predation
a predator kills or consumes all or most of another individual
standing defense
defenses against predators that are present even in their absence
-energy inefficient
inducible defenses
physical, chemical, or behavioral defense traits that occur in response to the presence of a predator
-energy efficient but take time to produce
keystone species
a species that has a much greater impact on the distribution and abundance of the surrounding species than its abundance and total biomass would suggest
food web
the network of exchanges of energy and nutrients among producers, consumers, and decomposers in an ecosystem
disturbance
any strong, short lived, disruption to a community that changes the distribution of living/nonliving resources
disturbance regime
most communities experience a characteristic type of disturbance
- predictable frequency and severity
primary succession
disturbance removes soil and its organisms as well as organisms above the surface
-glaciers, floods, volcanic eruptions, landslides
secondary succession
disturbance removes some or all of the organisms from an area but leaves the soil intact
early succession
time period after a disturbance that is dominated by species that are short lived, small in nature, disperse their seeds over long distances
late succession
time period after disturbance that is dominated by species that tend to be long lived, large, and good competitors
facilitation
the presence of an early arriving species makes conditions more favorable for the arrival of later species
sampling effect
more productive species are more likely to be found in areas with high biodiversity
species richness
how many species are present in a given community
species diversity
weighted measure that incorporates number of species with the species relative abundance
latitudinal gradient
species diversity declines as latitude increases
ecosystem
species present in a region + abiotic components
primary producer/autotroph
organism that can synthesize its own food from inorganic sources
gross primary productivity (GPP)
total amount of chemical energy produced in a given area and time period
cellular respiration
total energy needed to simply stay alive
net primary productivity
-energy that is invested in building new tissues or offspring
-total amount of chemical potential energy that is stored in organic material
NPP=GPP-R
R=energy used in cellular respiration, or lost
biomass
quantitiative amout of organic material
consumers
eat living organisms
decomposers
obtain energy by feeding on the remains of other organisms or waste products
trophic level
organisms that obtain energy from the same type of source
biomagnification
pollutants increase in concentration at higher levels of the food chain
nitrogen fixing plants
increase nitrogen in soil by storing it in their roots and releasing it when they die
-beneficial for other plants to grow
-breaks N2 molecules into -NH4
global warming
increase in the average temperature of the planet
global climate change
sum of all changes in local temperature and precipitation patterns that result from global warming
greenhouse gas
traps heat that has been radiated from earth and keeps it from being lost to space
phenology
timing of seasonal events
biodiversity
biological diversity
genetic diversity
total genetic information contained within all individuals of a population, species, or group of species
-measured by the relative species of all genes present in a group
endemic species
species found in a particular area and nowhere else
biodiversity hotspot
regions that are in most urgent need of conservation action
-areas where efforts to preserve habitat would have the highest return on investment
overexploitation
the main reason for the decline of marine species
habitat loss
the most important factor in the decline of terrestrial species
-logging, burning forests, building housing developments
habitat degredation
reduction in the quality of habitat
habitat fragmentation
parsing of continuous areas of natural habitats into small, isolated fragments
-can reduce habitats to a size that is too small to support some species
-can force species into a metapopulation structure
-creates large amount of degraded "edge" habitat
exotic species
a nonnative species that is introduced into a new area
invasive species
an exotic species (nonnative) that disrupts species native to the area
-can change local biotic and abiotic environments
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