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49 terms

Biology Review

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ecology
the study of the interactions of living organisms with one another and with their physical environment (soil, water, climate...)
habitat
the place where a particular population of a species lives
community
the many different species that live together in a habitat
ecosystem
it consists of a community and all the physical aspects of its habitat, such as the soil, water, weather
abiotic factors
the physical aspects of a habitat
biotic factors
the living organisms in a habitat
biodiversity
the number of species living within an ecosystem
pioneer species
the first organisms to live in a new habitat - small, fast-growing plants
succession
a somewhat regular progression of species replacement
primary succession
succession that occurs where plants have not grown before
secondary succession
succession that occurs in areas where there has been previous growth, such as in abandoned fields or forest clearings
primary productivity
the rate at which organic material is produced by photosynthetic organisms in an ecosystem
producers
organisms that first capture energy - include plants, some kinds of bacteria, and algae
consumers
those organims that consume plants or other organisms to obtain the energy necessary to build their molecules
trophic level
the specific level to which an organism in an ecosystem is assigned - used by ecologists to study how energy moves theough an ecosystem
food chain
the path of energy through the trophic levels of an ecosystem
herbivores
animals that eat plants or other primary producers - 2nd trophic level
carnivores
secondary consumers, animals that eat herbivores - third trophic level
omnivores
animals that are both herbivores and carnivores
detritivores
organisms that obtain their energy from the organic wastes and dead bordies that are produced at all trophic levels
decomposers
bacteria and fungi that cause decay and release nutrients back into the environment
food web
a complicated, interconnected group of food chains
energy pyramid
a diagram in which each trophic level is represented by a block, and the blocks are stacked on top of one another, with the lowest trophic level on the bottom
biomass
the dry weight of tissue and other organic matter found in a specific ecosystem.
biogeochemical cycle
the path of water, carbon, nitrogen, and phosphorus from the nonliving environment to living organisms, and then back to the nonliving environment
ground water
water retained beneath the surface of the Earth
transpiration
a sun-driven process in which water moves into the atmposhere by evaporationgg from leaves
respiration
all organisms engage in this process, in which oxygen is used to oxidize organic molecules during cellular respiration - CO2 is made
combustion
the process of burning in which CO2 is released into the atmosphere
erosion
as limestone is broken down, it releases CO2 that is made availible to other organisms
assimilation
the absorption and incorporation of nitrogen into plant and animal compounds
ammonification
the production of ammonia by bacteria during the decay of nitrogen-containing urea
nitrification
the production of nitrate from ammonia
dentrification
the conversion of nitrate to nitrogen gas
nitrogen fixation
the process of combinign ntirogen with hydrogen to form ammonia
population
it consists of all the indiciduals of a species that live together in one place at one time
population size
the number of individuals in a population - this can affect the population's ability to survive
population density
the number of individuals that live in a given area
dispersion
the way individuals of the population are arranged in space
population model
a hypothetical population that attempts to exhibit the hey characteristics of a real population
exponential growth curve
a curve in which the rate of ppulation growth stays the same, as a result the population size increases steadily J-curve
carrying capacity (K)
the population size that an environment can sustain
density-dependent factors
the limited resources - the rate at which they become depleted depends upon the population density of the population that uses them
logistic model
a population model in which exponential growth is limited by a density-dependent factor S-curve
density-independent factors
environmental conditions - those that don't depend on the number of organisms in a habitat
r-strategists
species found in rapidly changing environments that grow exponentially when environmental conditions allow them to reproduce
K-strategists
populations that grow slowly and that have small population sizes. They are limited by the carrying capacity and have long lifespans.
nonrandom mating
a situation in which individuals prefer to mate with others that live nearby or are of their own phenotype
stabilizing selection
selection eliminates extremes at both ends of a range of phenotypes, the frequencies of the middle phenotypes increase. fewer individuals in population with extreme phenotypes