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239 Cards in this Set
- Front
- Back
Levels of Biological Organization
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Subatomic particle; atom; molecule; organelle; cell; tissue; organ; organ system; multicellular organism; population; community; ecosystem; biosphere
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evolution is at ___ level
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population
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natural selection is at ___ level
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individual
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gene
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a unit of inheritance that is transmitted from parents to offspring. The place a particular gene resides on a chromosome is called a locus
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ecology
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the scientific study of the distribution and abundance of organisms and the interactions (abiotic and biotic) that determine distribution and abundance
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evolution
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changes in allele (an alternate form of a gene) frequencies over time
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pattern
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observable and quantifiable evidence from the natural world
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process
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the causes of the patterns
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models
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the formal scientific description of processes that produce particular patterns. depending on the level of support, these models often are considered hypotheses, theories, or scientific laws.
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Scientific Method: Observation
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observe, quantify, and characterize the natural world
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Scientific Method: Formulating Hypotheses
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create models/experiments with testable predictions to explain the observations
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Scientific Method: Testing Hypotheses
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use data from experiments or patterns in nature to test the predictions of the models
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science deals entirely with
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physical evidence. any reported scientific result can be repeated. Non-repeatable results are purged from the collective scientific endeavor.
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Scientific Method: Theory
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A system of ideas that has broad explanatory power and that has emerged intact after repeated attempts to falsify. Examples of theories include the theory of relativity and the theory of plate tectonics.
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Scientific Method: Hypothesis
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A proposed explanation for a particular set of observations. Hypotheses are much smaller in scope than theories and are much less well supported by data.
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Common usage of the term theory is very different than
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the scientific usage
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Hypothesis testing
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-manipulative experiments
-natural experiments -observational studies |
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manipulative experiments
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a controlled experiment in which the scientist manipulates some aspect of the system and observes its behavior. These experiments usually involve at lease on treatment and controls
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natural experiments
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the scientist takes advantage of some natural event that perturbs the system in a way that allows hypotheses to be tested
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observational studies
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the scientist makes predictions about a system that has not yet been studied based on the hypothesis and then collects data to see if the predictions are upheld
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Charles Laveran
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French army surgeon; found malaria in blood in 1880
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Ronald Ross 1897
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Demonstrated malaria transmitted through mosquitoes
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US organized several efforts to combat malaria on various occasions
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Panama canal (1905-1910), US Public Health Service (1914) got congress to support malaria control in military bases in southern US
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malaria eradication efforts not successful in many other areas
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-human ecology (money, resources, standard of living, politics)
-basic ecology (transmission year round in tropical areas) -evolution at work (mosquito resistance to pesticides; malaria resistance to drugs) -ecology at work (altered landscapes that promote transmission- dams, irrigation) |
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1947-1951 Eradication of malaria in US
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spraying homes and environment with DDT, draining swamps (urban development), human behaviors (window screens)
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how has malaria influenced human evolution?
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many traits including sickle cell anemia
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G6PD deficiency
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confers reduced risk from malaria
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Distribution of water is not static, powered by
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solar energy
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over ___ % of earth's surface covered by water
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71%
oceans (97%), polar ice caps and glaciers (2%), freshwater in lakes, streams, and ground water (<1%) |
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distribution of water
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heat
evaporation clouds precipitation ---consumed by organisms ---groundwater ---surface water |
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turnover time
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the time required for the entire volume of a reservoir to be renewed
(ex. atmosphere 9 days, rivers 12-20 days, oceans 3,100 years) |
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ocean circulation driven by
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winds under Coriolis effect
-moderate earth's climate |
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Gyres
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(Coriolis effect)
--clockwise currents in Northern hemisphere --Counter-clockwise in Southern hemisphere |
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Gulf stream moderates temperatures in
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northwest Europe
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largest ocean basin
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Pacific
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second largest ocean basin
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Atlantic
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smallest basin
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Indian
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Ocean Structure
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divided into vertical and horizontal zones
-each zone supports distinctive assemblage of life |
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Pelagic
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off the bottom
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Benthic
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on the bottom
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light in respect to ocean
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-about 80% absorbed in first 10m
-very little penetrates past 600m -leaves about 3400 m of deep black water- only bioluminescence |
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thermocline
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layer where temp. changes rapidly with depth
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upwelling
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winds blow surface water offshore, cold water rises to surface, brings up nutrients
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sunlight increases ___ of water, which decreases ___
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velocity; density
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warm water _____cooler water
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floats on top of; creates thermal stratification
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salinity and oxygen
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34 ppt to 36.5 ppt
-oxygen concentration low compared to air; varies with depth |
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decreasing light and temperature with depth produces
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a series of vertical habitat zones
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Littoral zone
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also called intertidal zone: extends between highest and lowest tidal levels
-periodically exposed to air: life adapted accordingly. -exposed to wide variation in light intensity |
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intertidal zone details
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-one of most dynamic environments in biosphere
-waves and tides affect distribution and abundance of organisms -isolated pools can see rapid increase in salinity -oxygen not limiting due to mixing caused by waves -differential tolerances to periodicity of air exposure leads to zonation of species |
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Neritic Zone location
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-between lowest tide level and edge of continental shelf
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Neritic zone
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-high productivity: sunlight and nutrients in sediment
-kelp forests (brown algae) and coral reefs |
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kelp forests and coral gardens
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shallow waters around land
-high diversity and productivity -corals confined to 30 degrees N and S limited by temp -Kelp in temperate water (like a forest) |
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Oceanic Zone
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-beyond continental shelf, seafloor drops rapidly to great depths.
-production strictly limited: low availability of nutrients -divided into several depth zones |
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Photosynthetic organisms are limited to
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upper epipelagic zone (photic zone)
--phytoplankton and zooplankton |
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due to size, oceans contribute 1/4 of total
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photosynthesis in the biosphere
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life in oceans exist at all
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depths
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chemosynthesis occurs near
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undersea hot springs
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Estuaries are found where
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rivers meet the sea
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salt marshes and mangrove forests are concentrated
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along low-lying coasts
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estuaries, salt marshes, and mangrove forests all driven by
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ocean tides and river flow
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physically dynamic systems of estuaries, salt marshes, and mangrove forests leads to
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chemical variability (salinity and oxygen)
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estuaries, salt marshes, and mangrove forests transport
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organisms, nutrients, oxygen, and remove wastes
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Rivers and streams can be divided along three dimensions
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-length (pools, runs, riffles, rapids)
-width (wetted/active channels) -vertical (water surface, column) |
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Riparian zone
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a transition area between the aquatic and upland terrestrial environments
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river currents
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erode land, carry food, renew oxygen; all affect type of life
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upstream
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few minerals, lots of oxygen, fast moving water
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downstream
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lots of minerals, less oxygen, slow moving water
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salinity of rivers and streams are ___ dependent
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soil; refects climate
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temp of rivers and streams
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usually tracts air temp
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species rich in ___ rivers
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tropical
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most of the world's freshwater resides in
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a few large lakes (great lakes contain 20% of freshwater in the world)
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Lakes: Littoral zone
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shallow near shore, rooted plants
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Lakes: Limnetic Zone
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open lake
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Lakes thermally ______ like oceans. Spring and fall get alot of _____
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thermally stratified;
mixing; in tropics at low elevation little mixing |
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Oligotrophic
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well mixed lakes, lot of oxygen, low biological productivity
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Eutrophic
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high productivity, low oxygen
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Energy Flow: Primary production
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Fixation of energy (production of new organic matter) by autotrophs in an ecosystem
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autotroph
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organism that can synthesize organic molecules using inorganic molecules (C02) and energy [light (photosynthetic or inorganic molecules (chemosynthetic) like hydrogen sulfide]
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Energy Flow: Rate of primary production
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amount of energy fixed over a given period of time
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Energy Flow: Gross primary production
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total amount of energy fixed by autotrophs
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Energy Flow: Net primary production
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Amount of energy leftover after autotrophs have met their metabolic needs (=Gross - Respiration), amount available to consumers
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Heterotroph
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organism that uses organic molecules both as source of carbon and energy
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Energy Flow: Photosynthesis
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conversion of light energy to the chemical energy of organic molecules
-basis of life for plants, cyanobacteria, many algae -ultimate source of energy for most heterotrophs |
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Energy Flow: Trophic Level
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position in a food web determined by number of energy transfers from primary producers to current level
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levels of trophic level
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-primary producers (1st level)
-Primary consumers (2nd level) -secondary consumers (3rd) -Tertiary consumers (4th) |
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Terrestrial Primary Production
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generally limited by temperature and moisture. High rates generally occur under warm, moist conditions.
However, soil fertility (nutrients like N and P) can also explain differences in terrestrial primary productivity |
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Aquatic primary production
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-generally limited by nutrient availability in marine systems, highest rates by marine phytoplankton are generally concentrated in areas with higher levels of nutrient availability (e.g., continental margins where have nutrient run-off from land, sediment disturbance caused by upwelling)
-open ocean tends to be nutrient poor -vertical mixing main nutrient source (but not much in tropical oceans) |
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control of primary production via tropic cascades
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- = influence of consumers on primary productivity propagate through food webs
-bottom up control and top down control |
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bottom up control
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primary production affected by physical and chemical factors like temperature and nutrients
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top down control
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primary production affected by consumers
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Energy losses limit
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the number of trophic levels in ecosystems
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how is energy lost
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-transfer from one trophic level to another (trophic dynamics)
-limited assimilation and consumption -consumer respiration -heat production |
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ecological efficiency
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the percentage of energy transferred from one tropic level to the one above it
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energy quality decreases with each
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successive tropic level
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as energy losses between trophic levels accumulate, eventually there is
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insufficient energy left to support a viable population at a higher tropic level
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ecosystems store some energy in the form of
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dead organic matter and biomass
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Nutrient cycles involve
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the storage (nutrient pools) and movement (nutrient flux) of nutrients in an ecosystem
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Nutrient mineral components do not require
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constant replenishment. Unlike energy, minerals are recycled but the recycling also requires energy
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Ecologists are interested in the factors affecting
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the distribution of nutrients and the rates of flux
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Global Phosphorous cycle does not include
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substantial atmospheric pool
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largest quantities of phosphorous found in
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mineral deposits and marine sediments
-much of this in forms not directly available to plants |
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phosphorous slowly released in terrestrial and aquatic ecosystems via
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weathering of rocks
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Nitrogen cycle includes major
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atmospheric pool - N2
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only nitrogen fixers can use ______ directly
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atmospheric supply
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most organisms need ____ nitrogen
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reduced
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Nitrogen cycle: energy demanding process
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-N2 reduced to ammonia (NH3)
-Cyanobacteria, some soil bacteria, bacteria in leguminous plants |
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Once N is fixed
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it is available to organisms
-upon death of an organism, N can be released by fungi and bacteria during decomposition |
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Under anaerobic conditions ___ converted back to _____
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NH3 back to N2
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Carbon Cycle
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moves between organisms and atmosphere (a large pool) as a consequence of photosynthesis and respiration
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In aquatic ecosystems, CO2 must first
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dissolve into water before being used by primary producers
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Although some C cycles rapidly, some remains
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sequestered in unavailable forms for long periods of time
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CO2 in the atmosphere...
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retards the radiation of heat from the earth back into space
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large increase in CO2 coincides with
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industrial revolution
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CO2 associated with
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burning of fossil fuels
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14C half life 5730 years; so..
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it is rare in fossil fuels; more 12C is released in atmosphere; can be measured in tree rings
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Greenhouse effect
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heat is trapped near the earth's surface by greenhouse gases
-absorb infrared and reemit most back to earth (30% solar energy reflected back by clouds, particulate matter, etc.; 70% absorbed by atmosphere/surface) |
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greenhouse gases
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water vapor, carbon dioxide, methane, ozone, nitrous oxide, and CFC's
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Decomposition necessary for
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recycling of minerals
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rate at which nutrients are made available to primary producers is determined largely by
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rate of mineralization
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mineralization occurs primarily during
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decomposition
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rate of decomposition in terrestrial systems
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significantly influenced by temperature, moisture, and chemical compositions
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plants and animals affect
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distribution and dynamics of nutrients within ecosystems
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decomposers (heterotrophs) then... (role in decomposition)
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break down the producers and consumers, releasing the minerals
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minerals can be lost from the system by
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water runoff or conversion to volatile compounds. (e.g. nitrates can be converted to nitrous oxides by soil bacteria)
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mature ecosystems like old growth forests and virgin prairies release _____ levels of minerals
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very low (steady state condition where loss equals gain)
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disturbed ecosystems typically release ___ levels of minerals
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large;
-plowing of prairies and clear cutting of forests= major disturbances -may take centuries for the ecosystem to return to the steady state condition |
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idea of community stability usually includes two related concepts
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-communities have some kind of equilibrium state that is stable over time if the environment does not change
-communities return to their equilibrium stat after a disturbance that alters community structure |
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regular change in community composition is called
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succession
(one set of species succeeds a previous set) |
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succession
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gradual change in plant and animal communities in an area following disturbance. Each stage of changed called a sere
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primary succession
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on newly exposed geological substrates not yet modified by organisms (e.g., on a lava flow, new lake after glacial retreat)
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secondary succession
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following disturbance that does not destroy soil (e.g., after a forest fire)
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Climax community
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-late successional community that remains stable until disrupted by disturbance
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climax community not prone to
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invasion by non-climax species
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climax communities... (composition)
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renew themselves
-composition is determined by the interaction between plant species and abiotic factors (climate, soil moisture, etc. --the biomes are climax communities) |
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pioneer community
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first species in successional sequence
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Characteristics of Succession: tend to see increase in...
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species composition
--see in primary and secondary succession and in different habitats |
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As diversity and composition change, ecosystem properties
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can change;
--tend to see increase in biomass, primary production, respiration, nutrient retention --physical and biological systems are inseparable |
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why would N increase and P decrease in soil during succession?
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As nitrogen fixing organisms colonize, more atmospheric nitrogen is fixed into the ecosystem and because the primary source of phosphorus is through weathered rocks, the existing phosphorus in the soil will likely be depleted over time
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Chronosequences
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a series of communities or ecosystems representing a range of ages or times since disturbance (e.g., Glacier Bay ~500-1500 years)
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Hawaiian Islands have formed over..
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hot spots on the Pacific tectonic plate, forming an island chain varying greatly in age
--4 million years of ecosystem change (different patterns of nutrient distribution across the chronosequence. P limiting in later succession, N limiting early on in succession |
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Mechanisms of succession
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facilitation, tolerance, inhibition (facilitation and inhibition appear to be main mechanisms)
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facilitation
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only certain species can colonize (pioneers), which modify environment. New environment less suitable to pioneers and more suitable for new species. each stage paves way for the next
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Tolerance
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initial colonization not limited to pioneers can have juveniles of climax community. No facilitation or inhibition. Later successional species are those tolerant of environmental conditions occurring in succession. Climax community reached when pool of tolerant species exhausted
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Inhibition
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Initial colonization not limited to pioneers can have juveniles of climax community. Early arrivals modify environment that inhibits any new colonization by any species. Later successional species can only colonize if a disturbance opens new habitat. These later species come to dominate because they resist disturbance
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stability
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absence of change. Persistence in the face of disturbance.
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Resistance
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Ability to maintain structure and function in face of potential disturbance
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Resilience
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Ability to recover from disturbance
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Stability may be due to
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lack of disturbance (e.g., not much disturbance in deep sea bottom environments) or community resistance or resilience in the face of disturbance.
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stability depends on
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resolution an area is investigated
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difficulty in studying community and ecosystem stability
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-need long term data to understand normal background fluctuations, but ecosystem turnover extends beyond our lifetime.
-hard to find true replication -what two large scale ecosystem environments are truly alike. |
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LUCA
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(last universal common ancestor) most recent common ancestor of all extant organisms
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cenancestor
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another name for LUCA
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Primoridal form
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the first living thing
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phylogeny
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evolutionary history of organisms
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phylogenetic tree
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graphical representation of phylogenies
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what is needed for life as we know it?
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information storage
energy acquisition and utilization reproduction |
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RNA can..
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store and do biological work- ribozyme has genotype and phenotype
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support for RNA (what was early life based on)
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-only known molecule that carries genetic info and can catalyze chemical reactions
-in modern cells, RNA catalyzes protein synthesis -ribosomes (conserved component of metabolic machinery) -can evolve; but self replicating RNA has not been demonstrated or discovered |
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Primordial or Prebiotic soup
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1. assemble simple molecules into building blocks for complex polymers
2. assemble polymers that can store information and catalyze reactions 3. add membranes and an energy source to make a living organism |
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Stanley Miller 1953 demonstrated that
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many of the compounds necessary for life could be produced in a "pre-biotic" atmosphere
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Panspermia
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life from an asteroid?
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oldest rocks that contain any signs of life are
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3.7-3.85 billion years old
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how can we trace back to find common ancestor?
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use DNA to reconstruct phylogenies; however not all genes have the same evolutionary history
-lateral gene transfer? |
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igneous rock
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created from molten material
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sedimentary rock
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deposition and solidification of sediments
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metamorphic rock
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results from the transformation of igneous or sedimentary rock under high pressures and temperatures
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most fossils found in
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sedimentary rock
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relative dating: superposition
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younger rocks deposited on older rocks
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relative dating: original horizontality
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lava and sedimentary rock laid down horizontally; any bending or tipping occurred after deposition
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relative dating: cross-cutting relationship
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intruding rocks are younger than host rocks
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relative dating: inclusions
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boulders or other fragments are older than host rock
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relative dating: faunal succession
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early fossil forms simple, more recent similar to extant taxa
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absolute dating
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radiometric dating
tree rings |
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absolute dating: radiometric dating: Rubidium-strontium
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10 million-4.6 billion (effective dating range); dates volcanic and metamorphic rocks
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absolute dating: radiometric dating: Uranium-lead
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10 million-4.6 billion; igneous and metamorphic rock
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absolute dating: radiometric dating: Thorium-lead
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10 million-4.6 billion;
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absolute dating: radiometric dating: Potassium-argon
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100,000 - 4.6 billion; volcanic rocks
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absolute dating: radiometric dating: Carbon-14
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100- 100,000; any carbon bearing material (wood, bones, shells, charcoal, cloth, paper, animal droppings)
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Alfred Wegener in 1915 proposed
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plate tectonics (continental drift)
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plate tectonics not fully accepted until
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1960
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maximum velocity of plate movement
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5-10 cm per year
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three types of plate boundaries
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-divergent
-convergent -transform fault boundaries |
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Divergent plate boundaries
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the plates are moving apart; produces ocean floor (atlantic)
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Convergent plate boundaries
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the plates are moving towards each other. can produce mountain ranges (himalayas)
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Transform fault boundaries
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the plates are grinding past each other. earthquakes are common
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What is a fossil
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any trace left by an organism that lived in the past
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types of fossils
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-compression fossils
-casts and molds -permineralized fossils -unaltered remains |
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how good is the fossil record
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bad; incomplete and biased
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geography bias
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depositional areas (lowlands, marine)
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taxonomic bias
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bones and shells amenable to fossilization (best fossil records left by marine invertebrates with hard skeletons)
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temporal bias
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earth's crust is recycled so older rocks rarer
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consequence of bias and incompleteness of fossil record
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the gradual origins of species and higher taxa have not been documented for the most part
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species
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temporally distinct parts of a single evolutionary lineage
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chronospecies
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different forms of a species
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cladogenesis
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splitting of a lineage (B and C are chronospecies from A, but B and C are different species from eachother)
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pseudoextinction or taxonomic extinction
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occurs when a lineage changes so much that its original name disappears
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real extinction
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a lineage fails to leave any descendants
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Proterozoic era time
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2.5 bya to 543 mya
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proterozoic era characterized by
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prokaryotes and eukaryotic algae
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first evidence of animal life appeared
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less that 1 BYA
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oldest fossils of multi cellular animals
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640 million years old
|
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Edicaran Fauna
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Precambrian animal
-soft body, no skeleton -sea floor -difficult to interpret relationships to life in Cambrian |
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Paleozoic era: cambrian period
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cambrian explosion started about 530 mya
-almost all of the modern phyla and classes of skeletonized marine animals suddenly appear in the fossil record |
|
what precipitated the cambrian explosion?
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-diversification from increasing O2 levels
-vacant ecological habitats -key innovations related to multicellularity and the organization of developmental processes may have evolved |
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Paleozoic era: Ordovician (495-439 mya)
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lot of diversification with new classes and orders; first vertebrates and land plats, ended with one of the five largest mass extinctions of all time
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Paleozoic: Silurian (439-409) and Devonian (409-354)
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-origin and diversification of fishes
-plats diversify on land -trees present by late Devonian -terrestrial vertebrates arose in late devonian -mass extinction at end of devonian |
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Paleozoic: Carboniferous (354-290) and Permian (290-251)
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Widespread tropical swamp forests, gigantic dragonflies, reptiles, mammal like reptiles;
-worst extinction ever at end of Permian |
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Mesozoic Era (251-65 mya)
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triassic, jurassic, cretaceous periods; mass extinction at end
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Cenozoic Era: Paleocene epoch (65-55.6 mya) (cenozoic--tertiary--paleogene--paleocene)
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mammalian radiation after the extinction of the dinosaurs
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Pleistocene Epoch (1.8 mya to 10,000 ya)
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repeated glaciations. origin and extinction of large mammals. origin of modern humans. extinction of many taxa
|
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Holocene Epoch; the last 10,000 years
|
agriculture, domesticated animals, digital watches, etc. Also in the midst of what might be the worst mass extinction ever.
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Internal Abdominal Obliques
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Attachment 1: Thoracolumbar fascia and ribs
Attachment 2: Linea alba, Tuber coxae, prepubic tendon Action: Aid in urination, defecation, parturition, & respiration. Lateral flexion. Support/contain abdominal cavity contents. Innervation: Ventral branches of thoracic and lumbar spinal nerves |
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major factor causing global variation in climate
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angle at which sun's rays hit the earth
|
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rainforests found
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near equator
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major deserts found
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near 30* N/S
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Coriolis effect
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causes apparent deflection of winds clockwise in N hemisphere and counterclockwise in S hemisphere
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soil
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complex mixture of living and non living material
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soil: O horizon
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Organic layer freshly fallen organic material
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soil: A horizon
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mixture of minerals, clay, silt, and sand
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soil: B horizon
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clay, humus, and other materials leached from A horizon- often contains plant roots
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soil: C horizon
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weathered plant material
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biomes
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distinguished primarily by their predominant plants and are associated with particular climates
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gross primary production
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total energy assimilated by photosynthesis
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net primary production
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total energy available to consumers
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difference between gross and net primary production
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the energy used in respiration
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tropical rain forests
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within 10* latitude of equator
-little temp and precipitation variation -nutrient poor soil -highest productivity |
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Tropical seasonal forest/savanna
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-grassland w/ scattered trees
-fluctuation in precip. -fires |
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subtropical desert
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-very low precip. little seasonality
-30* N/S -plants sparse to absent -low animal abundance; high biodiversity |
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Woodland/shrubland; (mediterranean/Chaparral)
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-mild wet winters; severe summer drought
-thick, evergreen, shrubby vegetation -fires |
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temperate rain forests
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-mild winters; heavy winter rain; summer fog; tall evergreen forests
-biodiversity much lower than tropical rain forest |
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Temperate seasonal forests
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-deciduous forest
-hot summers, mild winters with freezing -rainfall abundant with long growing season -multiple forest layers -fertile soils -biodiversity higher than boreal forest |
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Temperate grassland/ desert
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-also known as prairies or steppes
-drier that temperate forests, but same latitudinal range -rich soils -cold winters; hot summers |
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Boreal Forest (Taiga)
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-Northern hemisphere
-low fertility soil -evergreen conifers -high animal density |
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Tundra
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-high latitude
-avg temp below freezing -small plants -short growing season -peat (organic matter in soil) -permafrost |
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if permafrost melts, peat will..
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decompose at a higher rate, thereby releasing CO2
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Mountains
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-concentrated in belts of geological activity
-climate changes with elevation and latitude -soils well drained and thin -flor and fauna change with elevation |
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as elevation increases
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precip. increases; temp decreases
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globally driven deserts
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30* n/s
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locally driven deserts
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on sides of mountains (rain shadow effect)
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