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185 Cards in this Set
- Front
- Back
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Communities change from day to night seasonally
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because these changes are cyclical, they are considered nondirectional
these include replacement changes, which maintain a steady state |
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Directional Change
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results in permanent alteration of the community
may be due to climatic change (ice ages, etc.) over longer time periods may be evolution and extinction of species (Chestnut blight; giant ferns seen in coal beds) |
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Succession
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series of community changes resulting in a climax (stable) community
it is a directional change that occurs although climate and available species don't change |
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Canopy Replacement
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dominant trees die and fall apart or are knocked over by weather (wind, ice)
a gap is created, sunlight reaches the ground, and new trees or growing trees fill the gap (gap-phase replacement) |
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Mathematical Probabilities of Replacement...
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by same or different species can be estimated using transition matrices (Markov analysis is used to interpret future events in the forest)
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If probabilities are about equal for replacement species...
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the forest is in climax
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If probabilities are different,
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forest is transitional
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The Markov analysis allows...
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prediction of the climax forest assuming constant probabilities
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Fluctuation
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alterations in communities due to shifts in habitat factors
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Fluctuation Example Ponds
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ponds become marshes and vice versa as the water table fluctuates
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Fluctuation Example Dust Bowl
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droughts normally occur on the plains (as do wet years)
poor land use practices subjected the land to winds moreso than in history the combination of events led to changed in flora based on abilities to survive drought and soil loss conditions later, abundances of organisms finally returned to pre-drought proportions |
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Dust Bowl Message
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drought will come again so land use must be planned for living with dry conditions
wind rows are being cut in Oklahoma again.. we forget |
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Succession
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the replacement of communities leading to one that is stable
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Pioneer Community
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in a barren area, the first set of organisms to colonize forms the pioneer community
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Pioneers
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may be only a few species, usually those that can tolerate more extreme conditions
these alter conditions (shade so ground temperature and moisture change) which allows other species their microhabitat requirements |
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Climax Community
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diversity increases with new microhabitats until stable conditions develop which is a climax community
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Sere
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the successional series of communities
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Seral Stages
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individual communities within the series
ex. annual --> perennial --> shrub --> early forest --> climax forest agricultural and forestry practices set back succession: we seem to not want climax forests |
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Primary Succession
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designates succession on an area that never supported a community
ex. lava flow |
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Secondary Succession
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area once supported a community but succession was set back
ex. abandoned farm, burned forest secondary succession usually is faster than primary |
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Microsere
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just as some organisms require specific habitat conditions (microhabitat), communities have a variety of microhabitat that may be undergoing successional stages; the area is a microsere
ex. temporary ponds, dead animal carcasses, fallen trees |
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The Role of Reactions in Succession
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dominant organisms of each seral stage make the area less favorable for themselves but more favorable for organisms of the next stage
ex. more shade tolerant organisms appear as shade becomes deeper in forest succession |
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Climax Community
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is in dynamic equilibrium (changes occur but they perpetuate the community)
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Climax Community
Characteristics 1-4 |
1) tolerates its own reactions
2) climax tends to be more mesic for the climate in which it occurs (pioneer communities tend to be xeric or hydric) 3) climax is more organized (complex) 4) higher diversity |
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Climax Community
Characteristics 5-7 |
5) climax tends to be of species long-lived, large, K-selected
6) gross primary production tends to about equal community respiration (humans prefer earlier successional stages because production > respiration, thus we envision a harvestable surplus) 7) stability of the climax ecosystem is high |
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Paleoecology
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the use of modern understanding of ecological relationships to interpret the prehistoric ecology
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Paleoecology assumes Uniformitarianism
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that physical, chemical, geological, and biological processes have been consistent over time
study the processes of today to interpret the past |
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Paleoecology Problems
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1) soft organisms don't fossilize well - sample may be unrepresentative
2)different organisms vary in likelihood of being caught by events leading to fossils 3)sample may represent several communities due to long periods that often may be represented 4)must often rely on inference because empirical data is lacking |
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Paleoecology Typical Fossils
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pollen, bone, petrified stems, shells
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Autecology
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ecology of individual organisms
often is applied to interpretation ex. a species requires a warm climate and its fossils are found in a colder climate, infer from autecology of that species that the local climate was warmer in the past |
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Reconstruction of Vegetation during the Paleocene
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(65 million years ago)
indicates the climate was warmer, and that Arkadelphia was a part of a gulf |
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Pleistocene
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during the Pleistocene there were several glaciations (ice ages) affecting distribution of organisms
-the southern Appalachians and highlands of Arkansas served as refugia for many species, which accounts for distributions of the species (Townsend's big-eared bat, wood frog, zigzag salamander, etc.) |
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Physiognomy
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landscape emphasis is on vegetation, characters that determine it include:
1)growth form - dominants are trees, or shrubs, or herbs 2)function - deciduous or evergreen 3)size 4)coverage - how extensively the vegetation covers the substrate 5)leaf size and shape - broadleaf or needle-leaf 6)leaf texture - succulent, thin, hard |
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Using these Characters, about 5 Discernable Physiognomic types are easily recognized:
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1)forest
2)savanna 3)thicket 4)grasslands 5)desert |
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forest
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dominated by trees spaced such that their crowns touch
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savanna
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scattered trees in a grassy or shrubby area
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thicket
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tall shrubs or small trees in dense aggregation
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grasslands
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trees scarce, grass dominant
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desert
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plants sparse and scrubby, substrate makes up most of landscape
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biomes
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communities of geographical extent characterized by a distinctive physiognomy based on the climax dominants (plant and animal)
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Temperate Deciduous Forest
Location |
eastern North America, western Europe, Japan, Eastern China, Chile
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Temperate Deciduous Forest
Seasons |
warm summer, cool winter; generally high precipitation
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Temperate Deciduous Forest
Soil |
soil usually acidic due to leaching of calcium
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Temperate Deciduous Forest
Dominant Plants |
dominant plants broad-leaf deciduous trees
spring ephemerals bloom prior to leaf out of trees in North America, maples are dominant in North and Oaks in South |
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Temperate Deciduous Forest
Arkansas Biome had Subdivisions |
1)oak-hickory dominated by white and black oaks and a variety of hickories
2)oak-pine dominated by loblolly and shortleaf pines, white oaks and hickories this is most of southwest Arkansas with rolling to flat topography |
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Temperate Deciduous Forest
Animals |
adapted in some cases for tree life with prehensile tails (white-footed mice, opossums), adhesive toe pads (tree frogs), skin flaps for gliding (flying squirrel)
winged vertebrates (birds, bats) have shorter, deeper wings for maneuverability |
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Temperate Deciduous Forest
Seasonaility |
makes the community vary
-insects most numerous when vegetation abundant, insect predators follow them during harder times, some migrate (birds) or hibernate (woodchuck) |
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Temperate Deciduous Forest
Edge |
much more common now, thus forest edge species are more common now than in the past; therefore, present studies of the fragmented forest really do not show us the conditions that led to its development
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Arctic Tundra Biome
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north of the tree line
growing season short (100 days or less), winters long and cold desert like precipitation (< 25 cm/yr) low diversity of plants and animals |
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Arctic Tundra Biome
Permafrost |
lower layers of soil remain frozen, forming a barrier, so soil become waterlogged in summer: ponds, lakes, muskegs (a type of bog) are common
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Arctic Tundra Biome
Vegetation Short |
grasses, sedges, mosses, lichens - low growth forms; self-pollinate often because insect pollinators are undependable
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Arctic Tundra Biome
Animals |
lemmings, voles and their predators, caribou, muskox, ptarmigans, snowy owls, arctic hare, arctic fox, polar bear
blackflies, mosquitoes abundant many animals have a white coat seasonally or year-round |
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Antarctic
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most is ice with some ground underneath
a few favorable locations in oceans or reaching toward South America are milder 2 flowering plant species occur, also algae, lichens, mosses with animals like mites and collembolans vertebrates depend on marine systems - seals, penguins |
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Boreal Coniferous Forest
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northern North American and northern Eurasia (called taiga there)
cold winters; short, mild summers soil a think mor humus, acidic, infertile lakes, ponds, boggy areas with peat (muskegs) common |
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Boreal Coniferous Forest
Short, Low Diversity Conifers |
evergreen, needle-leaves
evergreen means not having to grow new leaves (infertile soil) needles shed snow |
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Boreal Coniferous Forest
"Spruce-Moose Biome" |
a few large herbivores, grizzlies, wolves dominate
snowshoe hare and lynx have broad, spreading feet for "showshoes" |
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Alpine Tundra
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above the tree line on mountains
name derives from tundra appearance in higher (alpine) elevations within other biomes geographically short growing season, long cold winter |
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Alpine Tundra
Compared to Arctic |
alpine has more precipitation, less extreme photoperiods, stronger winds, greater daily temperature fluctuations, better drainage, more grass, sedge, and forb, and less lichen
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Alpine Tundra
Animals |
pikas (rabbit-like mammals), yellow-bellied marmots are characteristic mammals, other animals migrate from lower elevations seasonally
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Alpine Tundra
Importance to Water Relations |
because a large portion of stream flow is generated by snow melt
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Temperate Grassland
Seasons |
summers hot, winters cold to mild
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Temperate Grassland
Growing Season |
1/3 or more of year; less in northern latitudes, greater in southern
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Temperate Grassland
Dry Period |
a dry period after mid-summer predisposes grasslands to fires, which holds back succession
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Temperate Grassland
Different Areas |
calles prairie, plains, steppe (Russia), pampas (Argentina)
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Temperate Grassland
Soil |
soil neutral to basic, fertile, high in organic matter
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Temperate Grassland
Vegetation |
grasses dominate, but in the eastern portion in North America becomess a mosaic with trees
fire prevention leads to invasion by woody plants |
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Temperate Grassland
Animals |
high productivity results in high diversity of rodents (granivores) - even grasshopper mice (rodent carnivore because grasshoppers abundant)
many hawks, reptiles, prairie dog and ferret, bison, pronghorn |
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Desert
Location |
occurs in arid rain shadows of mountains, along coasts next to cold ocean currents, and in the interior of continents
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Desert
Rainfall |
rainfall < 10" yearly and evaporation is high (potential > rainfall)
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Desert
Growing |
growing season is long
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Desert
Topography |
often includes low flat areas that temporarily fill as playa lakes (important for shorebird mirgrations, etc.)
short streambeds (arroyos) carry water after mountain snow melt or thunderstorms |
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Desert
Vegetation |
xerophyte plants most common, often spiny
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Desert
Animals |
must be adapted to conserve water
kangaroo rats produce metabolic water, conserve during waste elimination reptiles have behavioral thermoregulation amphibians rare: spadefoot toad - breed, develop, mature in about 2 weeks |
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Tropical Rain Forest
Location |
occurs generally within 20 degrees of the equator; mostly Amazon, western Africa, Indonesia
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Tropical Rain Forest
Precipitation |
high 200-1000 cm (80-400 inches)
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Tropical Rain Forest
Temperature |
varies little: about 27 degrees Celcius (80 degrees Fareinheit)
daily range may exceed range of monthly means |
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Tropical Rain Forest
Light |
intensity near ground is low, humidity near saturation
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Tropical Rain Forest
Soil |
acidic so leached, have little horizon development, and no humus-rich layers
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Tropical Rain Forest
Nutrient Cycling |
occurs within the biotic portion of the system
logging or deforestation reduces potential productivity |
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Tropical Rain Forest
Typical Climax Forest |
has open understory due to low light penetration
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Tropical Rain Forest
Plants |
mostly broad-leaved evergreens usually forming 3 layers
other plants are more common n rainforests: -epiphytes: plants growing on other plants (allows them to reach sunlight) -lianas: vines rooted in soil but climbing to canopy (vanilla, philodendron) usually no species dominate, species diversity is high |
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Tropical Rain Forest
Competition for Light may be Keen |
strangler fig germinates on a branch in the canopy, roots slowly grow to the ground and may outcompete the host tree for light, thus killing it
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Tropical Rain Forest
Animals |
animals also are diverse and many are canopy adapted
some amphibians use water caught in vegetation for reproduction and never come to the forest floor mammals, snakes, frogs, and lizards may glide using skin flaps of flattened bodies New World monkeys have prehensile tails sloth - hangs upside down, very slow, algae grows in the fur and is fed on by moths |
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Tropical Savanna and Grassland
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tropical latitudes that are more arid
largest is in Africa generally open with some trees usually 3 seasons: 1)warm and rainy, 2) cool and dry, 3) hot and dry large ungulates calve near the start of the rainy season |
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Tropical Savanna and Grassland
Soil |
acidic and leached, organic matter is low
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Tropical Savanna and Grassland
Soil Formation |
termites important in soil formation because they bring soil to the surface
mounds oriented facing the sun morning and evening, but bladelike at noon termites process the litter and are a prey base (aardvark, aardwolf- a hyaena) |
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Tropical Savanna and Grassland
Animals |
African savanna has many large grazers: zebra, wildebeest, gazelles and browsers: elephants, giraffes and predators: lions, cheetahs, leopards
large birds occur: ostrich (Africa), rhea (South America), emu (Austrailia) many migrate during dry season to moister areas |
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limnology
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study of freshwater systems
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Origin of Lakes (lentic systems)
Kettle |
glaciers may retreat leaving a block of ice buried in the drift - called a kettle, it is common in the Great Lakes Region
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Origin of Lakes (lentic systems)
Tarn |
glaciers dam valleys with moraine, forms a reservoir
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Origin of Lakes (lentic systems)
Oxbows |
meandering river cuts off part of itself
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Origin of Lakes (lentic systems)
Caldera and Maar |
volcanoes become inactive and the crater fills with water
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Origin of Lakes (lentic systems)
Karst |
underground streams cut caverns which collapse (sinkholes)
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Origin of Lakes (lentic systems)
Impoundments |
damming a stream: farm ponds to reservoirs
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Characteristic of Water
High Specific Heat |
much heat must be added to raise (or lost to lower) water temperature
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Water becomes a Thermal Trap
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daily air temperature changes may be great but water is slow to change daily or seasonally
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Water Heat Origin
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most heat is from solar radiation, either directly into the water or carried in by runoff
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Water and Light Energy
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about half of the total light energy is absorbed in the first meter
"red" wavelengths are lost more quickly, "blue" wavelengths penetrate deepest light penetration is reduced if water contains suspended material (turbid) |
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Trophogenic or Euphotic Zone
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upper are where oxygen from photosynthesis > metabolic use of oxygen
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Compensation Depth
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where oxygen production and use are equal lies at compensation depth
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Tropholytic (aphotic) zone:
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use > production
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Water Density
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most dense at 4 degrees Celcius, at lower temperature crystallization increases spaces between molecules so ice floats
a frozen pond surface acts as insulation for water below the ice |
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Thermal Stratification
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based on temperature - density relationships, cause by seasonal change
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Thermal Stratification
Spring |
sun and warm air melt ice cover and make upper layers same temperature as lower layers (4 degrees Celcius)
winds cause circulation (mixing) and results in spring overturn |
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Thermal Stratification
Summer |
warmth cause upper layer to have > temperature but less wind decreases mixing, so warmer (lighter) water circulates on top of colder (heavier) water
causes stratification |
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Stratification
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epilimnion - warm upper layer
metalimnioan (thermocline) - intermeadiate layer, change in temperature with depth is rapid hypolimnion - cool lower layer, may develop oxygen deficit because surface is not mixing with it |
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Thermal Stratification
Autumn |
lake loses more heat than it gains: surface water cool and sink until mixing occurs again (fall or autumn overturn)
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Thermal Stratification
Winter |
colder surface temperatures makes whole lake colder until surface might freeze
lower waters are slightly warmer, thus winter stratification occurs |
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Dimictic
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when lakes have 2 overturns, occurs in temperate climates
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Dimictic
Summer Stratification |
leads to low oxygen in the hypolimnion, sometimes resulting in "summer kills" of fish
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Dimictic
Oxygen Depletion |
during summer stagnation is most likely in highly productive (eutrophic) lakes where ther is more material to decay
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Dimictic
Winter Stratification |
may include a snow cover which further reduces light penetration and almost stops all photosynthesis in algae
decomposition and animal respiration may reduce oxygen below tolerance and result in "winter kills" |
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Meromictic Lakes
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almost permanently stratified due to chemical stratification (temperature doesn't override it)
usually caused by salt gradients have almost permanent anaerobic conditions at the bottom |
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Subdivisions of Lakes
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presence of sones depends on depth
littoral zone: shallow water near the shore supporting rooted vegetation - this area provides cover and substrate for fishes, invertebrates, and birds limnetic zone: open water area profundal zone: sediments of the substrate below limnetic zone |
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Habitat Groups
Benthos |
bottom dwelling organisms: sponges, flatworms, annelids, crustaceans, mollusks, aquatic insects
primary food source of organisms is detritus (dead organic material) Chaoborus uses the mud as shelter but makes nightly vertical migrations toward the surface to feed benthic diversity highest in littoral zone due to structural (habitat) diversity due to low oxygen levels, Chironomids (bloodworms) have hemoglobin to aid in respiration |
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Habitat Groups
Periphyton |
microscopic organisms attached to aquatic macrophytes, animals, or substrate
ex. diatoms, algae, some protozoans |
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Habitat Groups
Plankton |
floating microscopic organisms - movemtn more determined by water than organism effort
phytoplankton - plants - although tiny, still are important producers zooplankton - animals - predators on each other or "herbivores" on phytoplankton |
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Habitat Groups
Nekton |
swimming organisms: fish, some salamanders, birds (diving waterfowl), perhaps otter and beaver
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Habitat Groups
Neuston |
organisms associated with the surface file
water striders, some spiders, whirligig beetles (have split eyes) - set on top of the water on the surface film hydra, water fleas, mosquito larvae use underside of surface film for support |
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Heterotrophs Obtain Energy
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from planktonic algae, periphyton, macrophytes, and imported basin materials
autochthonous - produced in the lake allochthonous - imported (leaves, etc. of terrestrial origin) |
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Succession
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newly formed lakes generally are unproductive for some period of time (oligotrophic)
these lakes often are deep and have low phytoplankton populations |
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As Lakes age..
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organic materials accumulate, the lake becomes more productive (eutrophic)
increased phosphorus especieally is responsible for eutrophication modern runoff from sewage, fertilized fields or lawns, and phosphate detergents increases entrophication rate |
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Addition of Sediments
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as sediments are added from erosion, the lake becomes shallow and the distribution of vegetation is altered
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Vegetation Zones
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submerged vegetation: waterweed pondweeds - remain below surface
floating: water lilies, duckweed emergent: cattail, arrowhead, rushes swamp shrub: button bush, williows these vegetation zones move across the lake as it becomes more shallow |
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The Climax Successional Stage
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is a climax forest appropriate to the area
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Streams
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flowing bodies of water (lotic vs. lentic for standing water)
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Nature of the Stream Current
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determines the adaptations required for survival
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Natural Streams
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except for channelized streams, natural streams usually have faster and slower sections and deeper and shallower sections
these divisions may be present in succession or on opposite sides of the stream |
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Riffles
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swift flowing over rocks
turbulent flow cause aeration |
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Riffles
Plants |
usually are algae growing attached to rocks (in summer becoming slippery)
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Riffles
Animals |
have holdfast organs (sculpins, stoneflies), or avoid the direct current by living in the spaces under the substrate
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Rheotaxis
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orientation response to current - face upstream
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Pools
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backwater, side areas, or deeper portions where flow rate is much reduced
low velocity results in settling of particulate matter (heavier settles first, finer found farther downstream) |
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Small Forest Streams
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may be primarily allochthonous
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Larger Streams
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in which sunlight reaches the water have more autochthonous production and the system relies less in allochthonous material
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Largest Streams (Rivers)
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may have little autochthonous production and be too large for allochthonous material to be very important: for these, sloughs, backwater areas, and smaller tributaries may provide most nutrient materials
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Oceanography
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study of oceans
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Oceans
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cover 70% of surface
average 2 miles deep (up to 5-6 miles in trenches) salinity primary difference from freshwater (3.5% salt) becomes more dense with lower temperature (saltiness causes this - frozen sea water exclude salt) |
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Ocean Zones
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littoral: also called inter-tidal
neritic: over the continental shelf (benthic organisms are sublittoral) oceanic: open ocean (benthic organisms on the slope of the continental shelf are bathyal, in open ocean are abyssal) |
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Estuaries
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coastal bodies of water between ocean and freshwater; marshes, rivers, behind barrier islands
very productive due to nutrient influx with tides, ecotonal effects much of our seafood comes from there (filter-feeders and others biomagnify the chemical pollution from the rivers) |
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Coral Reefs
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develop only in warm water
consist of corals which secrete a calcium carbonate matix, which provides structural diversity to the habitat |
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Coral Reef Types
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fringing reef: those near the shore
barrier reef: a channel separates the reef and shore atolls: island is submerged, reef forms a ring |
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Coral Reef Fishes
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are diverse and typically have deep, thing bodies for maneuverability amoung the coral
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Cleaning Symbiosis
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developed on the reef
larger fishes appear and give signals that they are ready wrasses appear and enter the mouth to remove parasites the cleanee doesn't eat the cleaner (although it could) Symbiotic because: 1) larger fish gets rid of parasites, 2) wrasse has food brought to it |
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Cleaning Symbiosis Invader
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the situation has been invaded by a mimic that looks like a cleaner but actually tears our living tissue rather than removing parasites
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Mangrove Swamps
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covers up to 70% of tropical shorelines, mostly on muddy intertidal zones
mangroves are halophytes that build soil by trapping eroded sediments they also provide substrate for marine life and nest sites for many birds |
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Important Producer for the Bulk of the Ocean
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are the phytoplankton occurring in the neritic and oceanic zones
much of the production is by extremely small forms that even escape a plankton net, called nannoplankton |
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Temporary Members of Plankton
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some organisms (larval stages) are temporary members of the plankton
ex. barnacles, sea urchins, crabs, starfish - these use ocean currents for dispersal |
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Open Ocean
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due to its vastness, the open ocean is relatively unproductive, similar to semidesert land systems
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Upwelling
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areas in which nutrients are brought to the surface, more productive
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Wetlands
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where saturation with water is the dominant factor determining soil development and the biotic communities
commonly, the water table is at or near the surface |
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Marsh
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wetland dominated by grass-like plants: grasses, cattail, sedges, rushes
pHnear neutral to alkaline (basic) high water levels set back succession and maintain marsh important as sites for wildlife recharges ground water systems by allowing time for water to sink |
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Bog
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characterized by accumulation of peat, most common in glaciated north (muskeg)
a floating mat develops, and encloses the pond underneath continued accumulation of biomass fills the basin with peat pH usually < 5.0 (acid bog) |
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Nutrient Input in a Bog
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mainly is atmospheric: ombrotrophic "rain fed"
due to low nitrogen, some plants are insectivorous (sundew, pitcher plant, bladderwort) cranberries also are bog plants |
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Muskeg
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in tundra, pocosin (=poquosin) in southeast, cranberry bogs in northeast
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Swamps
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wooded wetlands
identified by type of trees: northern conifer, hardwood, cypress |
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Caves
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underground hollow, commonly in limestone areas carved by underground streams
no light deep within, twilight zone between humidity usually high, environment constant organic matter comes from outside: washes in or brought in (bats, bears, etc.) |
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Caves
Special Fauna |
troglobites - related to epigean (surface) fauna but tend to be white, eyeless, well developed tactile organs (long antennae, etc.)
ex. Typhlotriton spelaeus (grotto salamander) - places eggs near surface, maturing larvae move into cave |
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Phytotelmata
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microcosms forming in or on certain plants
hollow leaves of pitcher plants, tree holes with water used as watering holes or small ponds (aquatic invertebrates) |
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Pollution
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is a human reaction (an unfavorable modification of environment)
ex. yeasts produce alcohol and can eventually die in it, thus a pollutant |
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Human Reactions during the last century have become globally serious, reasons:
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1) humans have become the most widely distributed species (this is somewhat culturally and socially biased - WESTERN "civilization" has caused the greatest problems)
2)humans are large physically and in numbers |
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Human Reactions during the last century have become globally serious, reasons:
PART 2 |
3) use of energy subsidies (fossil fuel) has greater environmental consequences than other animals have
4) development of new chemicals places new materials into the biosphere the ecosystems have no evolutionary experience with --success of pesticides and herbicides is due to its evolutionary novelty |
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Pesticides
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intended to kill organisms (usually insects) that interfere with human interests
most are non-specific: affect more than just the target species |
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Human Cost is Hard to Measure:
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it is difficult to say a pesticide killed someone, although some people have died apparently due to close contact with concentrated pesticides (agricultural workers, etc.) but you can't prove it in court
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Persistence
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if biodegradation does not occur rapidly, the pesticide remains in the environment and may disperse
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Pesticide Example DDT
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DDT was not used worldwide but it found in body fat of organisms worldwide
biomagnification or bioaccumulation: persistent pesticides build up in tissues, may cause death, etc. -DDT caused egg-shell thinning in Bald Eagles, led to reporductive losses -DDT was banned in the U.S. but we still make it and send it to 3rd world countries - it comes back to us on bananas, coffee, chocolate, etc. sublethal effects: increase is greater than the sum |
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Synergistic Effects
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the effect is greater than the sum
potential for these effects is great, with over half a million man-made chemicals in everyday or restricted use |
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Resistance
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most "pests" are r-selected, so can undergo rapid evolution
pesticides become "new" fairly often because they beomce ineffective (the select for resistant pests) |
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Herbicides
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intended to reduce "pest" plants (weeds) in gardens or agriculture, sometime in war (agent orange)
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Agent Orange
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a defoliant
was said to be as safe as aspirin, not believed to cause cancer and birth defects |
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Radiation
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there is a certain amount of natural "background radiation" (including solar radiation and materials in the earth's crust)
the greatest concern is elevated levels (typically human induced) radiation can ionize molecules (especially a problem with DNA) |
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Radiation: 3 Types
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alpha: least dangerous
beta: can penetrate a couple of centimeters of tissue gamma: most powerful, can penetrate slightly into lead |
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Radiation can cause...
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sickness, death, cancer, mutations
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Power Source and Human Error
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Ralph Nader and pres. of AP&L, nuclear reactors: Chernobyl, 3-mile island, etc.)
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Wastes are a Problem:
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require storage in a geologically sound are for thousands of years before they degrade enough to be relatively no problem
problem of terrorists exploding nuclear wastes is a powerful concern store in third world or U.S. tribal lands |
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Water is Polluted by:
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1) sewage from municipalities and industry
2)pathogens from human wastes (fecal coliforms: rural septic tanks and wells relatively close together) 3)toxic materials - salt, mercury, pesticides, oil and gas 4)chemicals (such as fertilizers) 5)waste heat (thermal pollution) - electrical generating plants: water cools generators |
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Point Source
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an effluent pipe, etc.
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Non-Point Source
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a major source of pollution, pollutant is spread over some area
-storms that was lawns or streets -cotton rats that live next to highways have higher lead concentrations |
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Groundwater pollution
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groundwater is now polluted through landfills and becomes out well water
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Atmospheric Pollution
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most from buring fossil fuel
some of these products react in sunlight --> photochemical smog |
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Atmospheric Pollution Results
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eye and respiratory irritation to cancer in humans to various problems with other life
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Atmospheric Pollution
Problem with Solution |
big problem with solution is cultural: industrial technology societies tend to seek technological solutions rather than attempting to adjust behavior (a dollor affects out behvior more that a thought)
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Acid Rain
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sulfur and nitrogen oxides (esp. form burning fossil fuel) enters the atmosphere and falls back to earth as acid
normal rainwater is slight acidic due to dissolved CO2 (carbonic acid) |
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Acid Rain Results
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acid rain falls to earth and acidifies lakes, etc. (depending on local buffering capacity) which can greatly alter life in the system
-oligotrohpic lakes in the Adirondack Mountains |
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Genetic Engineering
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a controversial topic due to its potential benefits and costs
problem: would require a field test, which, if disastrous, might not be stoppable ex. engineer a microbe that can eat an oil spill -would solve probelms like oil spills (Exxon Valdez), also if inoculated into an oil well could remove fossil fuels (Saddam Hussein) |
