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
phosphorous cycle
phosphorous erodes from rock as inorganic phosphate, animals obtain it from their diet–phosphorous isn’t in the air
hydrologic cycle
renews the supply of water, involves an exchange of water between the land, ocean, atmosphere, and organisms, water enters the atmosphere by evaporation and transpiration, water leaves the atmosphere as precipitation
bottom-up processes
availability of resources such as nutrient minerals controls the number of producers, which controls the number of herbivores, etc; the make-up of soil determines what can live there
top-down processes
an increase in top predators cascades down the food web
What determines seasons?
the inclination of earth’s axis
Why is solar energy concentrated at the equator?
because of earth’s spherical shape and its axis tilt
How much solar radiation is immediately reflected back into space?
30% is reflected back into space immediately
How much of the sun’s total energy reaches earth’s outer atmosphere?
less than one billionth of the sun’s total energy reaches earth’s outer atmosphere
How much of the solar radiation that reaches earth is absorbed by the atmosphere?
47%
How much of the solar radiation that reaches earth drives the winds and ocean currents?
less than 1%
How much of the solar radiation that reaches the earth runs the hydrological cycle?
23%
How much of the solar radiation that reaches earth is captured by photosynthesis?
.02%
Where does all solar energy ultimately go after being used on earth?
all solar energy is ultimately re-radiated to space as heat
coriolis effect
the tendency of moving air or water to be deflected to the right in the northern hemisphere or to the left in the southern hemisphere
upwelling
an upward movement of water that brings nutrients from the ocean depths to the surface; where upwelling occurs, the ocean is very productive
rain shadow
an area that has very little precipitation, found on the downwind side of a mountain range, deserts often occur in rain shadows; when the rain cloud goes up the mountain it drops all of its moisture so there’s none left for the other side (desert)
regional precipitation differences
influenced by latitude, elevation, topography, vegetation, distance from large bodies of water, and location; precipitation is greatest where warm air passes over the ocean and then cools
effect of fire on certain ecosystems
fire frees the nutrient minerals locked in organic matter, removes plant cover, and increases erosion; many ecosystems, such as savanna, chaparral, grasslands, and certain forests, contain fire-adapted organisms; intermediate disturbance–there needs to be fire once in a while especially for the sequoias
