closed system
all matter or energy in system stays within system
open system
matter or energy is lost from the system, most energy systems (constant input of solar energy)
inputs
matter or energy entering systems
outputs
matter or energy leaving systems
matter
anything that has mass and takes up space, usually in a closed system
energy
the ability to do , usually in open system
kinetic energy
energy of motion, includes heat and forms of electromagnetic radiation
heat
total kinetic energy from all moving atoms, ions, and molecules in a given substance
electromagnetic radiation
wave form of energy in which wavelength and frequency are inversely related
longer wavelength
lower energy
potential energy
stored by matter and potentially available for use, includes chemical bonds and chemical energy
biomass
chemical bonds in organic molecules are a form of potential energy, LIVING MATTER
first law of thermodynamic (law of conservation)
energy can be neither created nor destroyed in any chemical or physical process
second law of thermodynamics
when energy changes from one form to another, some of the useful energy is always degraded into a lower-quality, more dispersed, less useful energy
entropy
tendency of energy in a system ot lose the ability to do work and thereby increase the disorder of the system
aerobic respiration
involves oxygen, opposite reaction of photsynthesis (produce carbon dioxide)
anaerobic respiration or fermentation
dont use oxygen, break down glucose in the absense of oxygen, end products: methane, alcohol, hydrogen sulfide
primary productivity
the rate at which sunlight energy is fixed into chemical bond energy of organic compounds
gross primary productivity (GPP)
total amount of organic molecules produced by photosynthetic organisms
net primary productivity (NPP)
amount of organic molecules that are AVAILABLE to the rest of the organisms in an ecosystem AFTER producers have used some of the glucose they produced. (less than GPP)
atmosphere
outermost sphere, contains air and atmospheric gases
hydrosphere
consists of the Earth's water
lithosphere
earth's crust and upper mantle which surrounds the inner core and mantle
biosphere
area in which living and dead organisms complete natural cycles
food chain
sequence of organisms, each of which is a source of food for the next, determines how energy and nutrients move from one organism to another through an ecosystem
food web
more realistic than food chain, because in nature most organisms have more than one source of food and shows that all organisms in an ecosystem are interconnected
trophic level
feeding level assigned to each organism in an ecosystem (types of producers and consumers)
autotrophs
organisms such as plants that make their own food, first trophic level called primary producers
heterotrophs
cannot obtain energy directly from the sun, consumers
primary consumer
usually herbivores (plant-eaters), feed on primary producers
secondary consumer
often carnivores (meat-eaters), feed on herbivores
tertiary consumers
carnivores that feed on other carnivores
omnivores
feeding on both plants and animals, often very succesful because of their ability to obtain nutrients from diverse sources
decomposer
specialized organisms that recycle nutrients in ecosystems, usually bacteria or fungi
detritivores
insects or arthropods or other scavengers that feed on the wastes or dead bodies of other organisms
ecological efficiency
percentage of usable energy transferred as biomass from one trophic level to the next
matter recycling
closed system completed by decomposer that break down organic matter into inorganic nutrients that can be re-used by producers
water cycle
collects, purifies, distributes, and recycles the Earth's fixed supply of water, powered by energy from the sun and the force of gravity
carbon sinks
organisms and systems that remove carbon dioxide from the atmosphere and store it
rhizoids
commensalist structure of n-fixing bacteria and plant root nodules
fixation
atmospheric N2 is converted into ammonia, NH3 and ammonium, NH4+, by bacteria in soil/water
nitrification
ammonia and ammonium are converted first into nitrite and then into nitrate
assimilation
plant roots absorb ammonium ions and nitrate ions for use in making molecules such as DNA, amino acids, and proteins
denitrification
bacteria in waterlogged soils and swamps convert ammonia, ammonium, nitrate, and nitrite back into N2 and N2O; these gases are then released back into the atmosphere
ammonification
decomposing bacteria convert organic wastes into ammonia and ammonium
fossils
mineralized or petrified replicas of skeletons, bones, teeth, shells, leaves, seeds, or impressions of items left in rock
biological evolution
the description of how life on Earth changes over time
natural selection
some individuals in a population will possess traits that make them more likely to survive and reproduce
chemical evolution
organic molecules, polymers, and systems of chemical reactions formed the first cells
microevolutions
mutations+genetic recombination change gene frequency in a population
speciation
evolutionary changes causes members of the same species to no longer be able to interbreed
genetic variability
within a population, how many different genes for the same trait are present within a population
mutations
random changes in the structure or sequence of DNA in a cell that can be inherited by offspring
natural selection
occurs when some individuals in a population have genes that produce traits that increase their chances of survival in a particular environment, or when that environment chagnes
three conditions for biological evolution by natural selection:
1)must be enough genetic variability for a trait to exist 2) trait must be heritable 3) trait must lead to differential reproduction, enabling individuals with the trait to leave more offsprings thatn other members of the population
population genetics
the study of alleles or genetic traits in a population
Hardy-Weinberg Law
list of criteria that would have to happen for gene pool NOT to change "ideal population"
1) mating would be random 2) there would be no mutation 3) no immigration or emigration so # of gene stay constant 4) population would be large 5) all organisms have
directional selection
individuals at one end of the curve of the phenotype distribution have higher fitness than individuals in the middle or other end
stabilizing selection
when individuals near the center of the curve have higher fitness than individuals at the other end of the curve
disruptive selection
individuals at the upper and lower ends of the curve have higher fitness that those near the middle
adaptation
any heritable characteristic that enables an organism to survive through natural selection and reproduce better under prevailing environmental condition
morphological adaptation
specialized structures for habitat such as camouflage
physiological adaptation
specialized function such as venom
behavioral adaptation
migration such as the mimicry
pre-zygotic barriers
cause individuals to not be able to interbreed (before fertilization) such as physical differences, behavioral differences, timing of reproduction
post-zygotic barriers
cause individuals to not be able to interbreed after fertilization such as fertilized egg will not develope and lack of reproductive capacity in offspring
geographic isolation
a small group separated from the main population will rotate only a few genes
reproductive isolation
some species show a preference for a particular color, dance, or display
adaptive isolation
species move out of home range
convergence
different species in the same habitat develop similar characteristics
coevolution
adaptations based on dependence on another organism
hybridization
indiciduals of two distinct species crossbreed to produce a hybrid
horizontal gene transfer
exchange genes without sexual reproduction
backgroud extinction
relatively fixed amount of species that go extinct over certain periods of time due to natural, changing environmental conditions
mass extinction
significant rise in extinction rates above background level
mass depletion
extinction rates are higher than normal but not enough to classify as a mass extinction