Ch 55 Flashcards
Hierarchy of structural levels
atomic level, molecular level, organelle level, cellular level, tissue level, organ level, organ system level, organism level, population, community, ecosystem, biosphere
ecology
ecology is the scientific study of the interactions between organisms and their environment; ecologists make predictions concerning a species distribution and abundance and test them with observations and experiments; the environment of any organism includes biotic and abiotic factors
abiotic factors
non-living chemical and physical factors such as temperature, light, water, and nutrients
biotic factors
the living components
organismal ecology
organismal ecology is concerned with the behavioral, physiological, and morphological ways individuals interact with the environment
population
a population is a group of individuals of the same species living in a particular geographic area
population ecology
examines factors that affect population size and composition
community
a community consists of all the organisms of all the species that inhabit a particular area
community ecology
examines the interactions between populations, and how factors such as predation, competition, and disease affect community structure and organization
ecosystem
an ecosystem consists of all the abiotic factors in addition to the entire community of species that exist in a certain area
ecosystem ecology
examines the energy flow and cycling of chemicals among the various abiotic and biotic components
biosphere
all of the earth’s communities
ecosphere
interactions of the biosphere with the abiotic environment on a global level; includes the atmosphere, lithosphere, and hydrosphere
energy flow through an ecosystem
linear, sun to producer to consumer to decomposer, trophic relationship may be expressed as food chains or as food webs (trophic=feeding)
ten percent rule
the tendency for only 10% or less of the energy in one trophic level to transfer to the next level, the other 90% is usually lost as heat
autotroph
an organism that synthesizes complex organic compounds from simple inorganic raw materials; also called producer or primary producer; auto=self
heterotroph
an organism that cannot synthesize its own food from inorganic raw materials and therefore must obtain energy and body-building materials from other organisms; hetero=other
energy pyramid
a graphic representation of the amount of energy that passes from one trophic level to the next, the pyramid shape indicates that most of the energy that enters primary producers (at the base) is lost before it reaches the highest level consumers (at the top)
ecological pyramids
express the progressive reduction in numbers of organisms, biomass, and energy found in successive trophic levels
gross primary productivity (GPP)
rate at which photosynthesis captures energy
net primary productivity (NPP)
energy that remains after plants and other producers carry out cellular respiration
DDT and it’s biological characteristics
DDT is a pesticide that was causing population declines in many non-target organisms, it displayed three biological characteristics: persistence–it doesn’t break down, there’s nothing to break it down, bioaccumulation–it’s stored because there’s nothing in the body to break it down, and biological magnification–it accumulates at each trophic level
carbon cycle
carbon dioxide is the most important gas, carbon enters plants, etc, as CO2, cellular respiration, combustion, and erosion of limestone return CO2 to the environment
5 steps of the nitrogen cycle
nitrogen fixation–involves the conversion of gaseous nitrogen to ammonia which fixes nitrogen into a form that organisms can use, nitrification–the conversion of ammonia to nitrate, assimilation–roots absorb ammonia, ammonium, or nitrate formed by nitrogen fixation and nitrification and incorporate the nitrogen into proteins, nucleic acids, and chlorophyll, ammonification–conversion of organic nitrogen compounds into ammonia and ammonium ions, and denitrification–the reduction of nitrate to gaseous nitrogen
