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60 Cards in this Set
- Front
- Back
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Ecology
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Study of the interaction between organisms and their environment
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Forest
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FOREST ECOSYSTEM: An ecosystem dominated by trees.
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Forest Ecology
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the study of the interactions of forests and their environments – this has no specific connection to “humans” but these interactions may be becoming increasingly important.
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Ecosystem
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A complex association of biotic and abiotic factors that interact to perpetuate or sustain itself, Tanley (1935) introduced the term but the concept goes far back to early historical descriptions of vegetation types
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Ecosystem Part 2
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Implications of this definition:
-Denotes that structure exists -Dependence on an external energy source -Performs specific functions – such as Carbon and energy flow Reproduction and perpetuation – response to change Nutrient (matter) Cycling -Interactions occur among organisms -Self-perpetuating (but not static or unchanging) |
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Environmental Science
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An offshoot of Ecology, study of ecological principles and their application to humans. Must understand ecology to understand environmental science and likewise you need to know forest ecology to understand urban forest ecology.
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Conservation
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Planned management of natural resources in order to promote sustainability and to prevent exploitation, destruction, or neglect. Note – This does NOT preclude use. (i.e. Frontier period to early 1900s until WWI, post WWII,)
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Preservation
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- first national park officially in 1891 (most US forests cut by 1900- Pennsylvania was essentially completely deforested and deer were imported from Michigan)
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John Muir
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Preservationist
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Gifford Pinchot
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Conservationist
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Homestead Act of 1862
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signed into law by President Abraham Lincoln- dispersed undeveloped federal land in the West of the Mississippi to those who agreed to improve it.
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George Marsh
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Man and Nature (early work of ecology) 1864 –both environmentalist/conservationalist
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Yellowstone Timber Preserve-
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Yellowstone National Forest was first established by the General Land Office on March 30, 1891 as the Yellowstone Park Timber Land Reserve. The land was, in effect, the first national forest.
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Keys to Population Growth
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A few thousand of our ancestors about 70,000 years ago – slow growth to that point!
Better developed hunting skills, weapons and diet, etc led to population growth BUT problems arose. Population growth and probably habitat loss (and climate change) led to the Pleistocene Overkill – 71% of North American large mammals became extinct 30,000 to 10,000 years ago! Loss of food sources (prey) and population growth led to the need (necessity is the mother of invention!) for agriculture. |
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Physiognomy
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- a way to view an ecosystem- by how the ecosystem looks
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Community Ecology
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a way to view an ecosystem- by the relationships among the species
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Landscape Ecology
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a way to view an ecosystem- . As a large geographic unit, including an entire unit of area that consists of a few to many communities and forest stand types
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Ecotone
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Changes in vegetation coincide with changes in the physical environment such as soil type, drainage, elevation, aspect, slope, etc. Changes may be rather abrupt but generally occur along a continuum leaving “mixed” or transition regions often called an ECOTONE
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Temporal Scale
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we may evaluate the forest over time (temporal scale) as in succession studies.
Temporal Scales: (usually vertical but multiple vertical perspectives can add a horizontal component). Forest changes over time, climate change, etc. What we see today is a product of time and constant change. , “let’s make things look the way they did before!” When is “before?” Note – these perspectives can also overlap. They aren’t meant to always be exclusionary |
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Spatial Scale
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Spatial Scales: (horizontal, can have various temporal components imbedded)
Looking at ecosystems from a spatial perspective - relationships in space, what grows where and why, interactions among organisms at some point(s) in space. The actual size of the space may vary – e.g. later – from micro- to macro-ecosystem levels. |
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Vertical Perspective
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(for viewing an ecosystem) – look at a single location or species studying how it functions and/or changes over time. For example, we might study its physiological ecology (gas fluxes, carbon accumulation across strata, water relations, etc.), reproductive biology, population dynamics (genetics, competition) or ecosystem level interactions across trophic levels.
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Horizontal perspectives
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How do adjacent ecosystems (or different forest stands in the large geoecosystem) interact? How do ecosystems change on the spatial scale and what factors contribute to this? This can also have a temporal component if we look at species changes or migrations over time.
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Major Geological Eras
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ERA – large time span
PRECAMBRIAN - > 600 million yrs ago (mya) PALEOZOIC: to 225 mya MESOZOIC: to 65 mya CENOZOIC: 65 mya to present |
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Pleistocene
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rather recent part of this period, about 10,000 to 20,000 years before present, end of the “ice-age” but remember there were several!
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Holocene
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about the last 10,000 years, recent.
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Scales of Temporal Change
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Daily/Seasonally/Yearly:
Wilting, annual plants, leaf fall and bud/leafout, population differences. Studied by physiology, experimental plots, etc. |
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Plant Migrations
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how do species move,
Either by vegetative reproduction or seed dispersal which can be natural or accidental (e.g. “white man’s footprint,” Plantago lanceolata). If by seed then what factors dictate the rate of migration? Seed production. Seed dispersal- By a variety of vectors (wind, humans and other animals, water, etc.). Seed germination. Seedling establishment and survival. Seed production |
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Migration Rates
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varies based on seed production, dispersal, etc. (some species move faster than others- ie aspen moves faster than spruce which moves faster than oaks…)
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Relicts or Refugia
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Some plants found where they “don’t belong” as relicts or refugia of a previous climate – e.g. northern plants in the southern Appalachians from glacial periods, refugia in Pacific NW and BC, “tropical” plants in the pollen record in KY and TN, occurrence of dawn redwood in China – closely related to redwoods in US but more tropical in nature.
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Climate Change
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Plants may not be where they “should” be by current climatic standards
Vegetation has been in constant state of change or state of flux due to climate changes as the major driving force, but superimposed on this are local and regional changes, disturbance and interactions between plants and soil (physiography/topography, soil development, water and nutrient availability and recycling) – plants and trees have migrated in front of or back behind the ice and climate changes. |
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Glaciation
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Some plants found where they “don’t belong” as relicts or refugia of a previous climate – e.g. northern plants in the southern Appalachians from glacial periods
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Gene
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(classic) the amount of genetic material that codes for a trait
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Allele
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different forms of a gene
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Genotype
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genetic composition, arrangement of base pairs
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Phenotype
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how something looks
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Ecotype
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genetically and phenotypically different forms of a species, heritable.
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Variability
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So what regulates the different phenotypic expressions? Genes or Environment?
To quantify: Vp = Vg + Ve Phenotypic variance (Vp) equals the total of genetic (Vg) and environmental variance (Ve) |
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Evolution
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- Evolution is any change across successive generations in the heritable characteristics of biological populations.
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Natural Selection
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Darwin. really a population phenomena in terms of change
Darwin: keep in mind the facts he had to work with!!! How much was known about DNA, genes, etc? The power of observation should not be lost! Strongest (best traits) will survive. |
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Heritability
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– genetic control of traits
H = Vg / Vp (high ratio = strong heritability) Situation A Situation B Situation C P1 = G1 + E1 P1 = G1 + E1 P1 = G1 + E1 P2 = G2 + E2 P2 = G1 + E2 P2 = G2 + E1 P3 = G3 + E3 P3 = G1 + E3 P3 = G3 + E1 |
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Common Garden
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testing Heritability (Turesson) corn seed test.
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Phytometer
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testing Heritability (Clements) testing species using variable conditions.
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Reciprocal Transplant
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involves introducing organisms from each of two or more environments into the other(s).
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Acclimation
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Plasticity – changes in phenotype in response to changes in the environment, short-term, NOT heritable. Plastic response are called Acclimations
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Adaption
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long-term change in GENE FREQUENCY, occur due to selective pressure and presumably because it gives a reproductive advance or increase in fitness (number of viable offspring).
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Adaptedness
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The ability of organisms to live and be successful under a variety of conditions is called adaptedness so adaptation is the heritable response or change in gene frequency of a population.
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Plasticity
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changes in phenotype in response to changes in the environment, short-term, NOT heritable. Plastic response are called Acclimations
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Species
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genetically and phenotypically distinct and reproductively isolated group of organisms.
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Speciation
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the formation of a new species
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Alloparic
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- (how species are formed) : geographic isolation, A. fraseri (Fraser fir) and A. balsamea (balsam fir).
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Sympatric
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(how species are formed) : ecological separation (phenology, local site differences), same region but different habitats or niches. Examples:
The extent and timing of specific pollinators – may lead to lack of opportunity for cross pollination Genetic incompatibility – fertilization may not occur across some species due to a random mutation. |
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Niche
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where, when and how a species remains distinct and successful with other species.
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Habitat
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an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism
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Clines
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consist of ecotypes or forms of species that exhibit gradual phenotypic and/or genetic differences over a geographical area
Clines may not be as distinct if you don’t take elevation into account – remember the 100 m elevation = 1O north rule |
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Examples along latitudinal or elevational gradients-
Some examples of how phenotypes vary across clines or gradients - |
Growth Cessation: Fig. 4.2 and 4.3
These may be influenced by photoperiod (length of night not day is generally what is important) and or temperature – both strong environmental signals Temperature is most notable along elevational rather than latitudinal gradients, where photoperiod may be a stronger cue (Ex. Growing aspen here.) What about leaf fall/senescence? Clines may not be as distinct if you don’t take elevation into account – remember the 100 m elevation = 1O north rule Growth Resumption: Leaf-out or budbreak also shows clines. It is frequently based on satisfaction of a chilling requirement, followed by environmental cues. Think about what signals might be important? Chilling alone does not lead to budbreak but may prevent it from happening early. If you put a tree seedling in a GC to meet its requirement it won’t break bud until you take it out. |
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Examples along latitudinal or elevational gradients-
Some examples of how phenotypes vary across clines or gradients - PART 2 |
The interactions of these make some interesting situation – some plants have modest or little chilling requirements and thus may break bud early – this can lead to horticultural / agricultural damage (peaches, apples, cherries, etc) but rarely “kills” entire plants, it just affects reproduction for that year.
Chilling may meet the precondition but bud break may not occur until a heat requirement is met (e.g. some number of degree days, a product of some temperature X time) – again the “early” flowering we may see (is it really early for the plant or just early for us?). Insect phenology is strongly influenced by this. Which is a more stable control? Photoperiod or temperature? To maintain balance across environments, some species may show gradients for heat requirement in terms of total heat units but the fractional component may be constant for that species – again this shows local ecotypic adaptation to growing season. The text shows several other specific examples for growing season, needle length, plant secondary chemistry, etc. |
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Seedling bank- number, viability, germination
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seedling recruitment and establishment- safe sites for initial germination, survival- reduced or limited by physical environment, predation, and competition (may adapt to their environment from the onset of germination – requirements such as temperature, fire, water, scarification, etc.
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Epigeous
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small, minimal food stored, pines and many angiosperms
In epigeal (epi=above) germination, the hypocotyl (hypocotyl is the stem below the cotyledons) pushes the cotyledons above ground. * The cotyledons function as leaves until the true leaves emerge |
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Hypogeous
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below ground, “nut” trees, oaks, hickory, walnuts, larger food storage
In hypogeal germination, the cotyledons remain below ground. * The epicotyl (stem above the cotyledons) grows and raises the plumule out of the soil. * Example - pea |
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DDioecious
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-– Acer, Populus, Alianthus, Ilex, Ginko, etc., each individual has reproductive units that are either merely male or merely female. That is, no individual plant of the population produces both microgametophytes (pollen) and megagametophytes (ovules).[ D
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