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Ecology
the study of the interactions of organisms with their environments
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Biosphere
composed of living communities and nonliving physical and chemical factors
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Aquatic Biomes
defined as fresh water and marine
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Terrestrial Biomes
categorized by climate and plant life
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Ecologists study environmental interactions at the leves of the
- organism
- population
- community
- ecosystem
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Global Ecosystem
- biosphere
- sume of all the Earth's ecosystems
- most complex level in ecology
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Biotic
- living
- includes all organisms
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Abiotic
- nonliving
- include atmospheric gases, energy, nutrients, and water
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Rachel Carson
- one of the first to percieve the global dangers of pesticide abuse
- concerns documented in Silent Spring in 1962
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Most important abiotic factors that determine the biosphere's structure and dynamics include:
- solar energy
- temperature
- water
- nutrients
- other aquatic factors
- other terrestrial factors
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Climate
often determines the distribution of communities
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Global climate patterns determined by:
input of solar energy and the planet's movement in space
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Earth's tilt causes the seasons
23.5 Degrees
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Uneven Heating causes
rain and winds
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Ocean currents
- have a profound effect on regional climates by warming or cooling coastal areas
- created by winds, planet rotation, unequal heating of surface waters, and location and shapes of continents
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Oceans cover 75% of the Earth's surface...
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Benthic Realm
- ocean bottom
- supports a variety of organisms based upon water depth and light penetration
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Pelagic Realm
- open ocean
- supports highly motile animals such as fish, squids, and marine animals
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Aphotic Zone
- vast, dark region of the ocean
- most extensive part of the biosphere
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Photic Zone
- portion of the ocean which light penetrates
- photosynthesis occurs here
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Intertidal Zone
- flooded by high tides and left dry during low tides
- wetland at the edge of an estuary or ocean, where water meets land
- salt marshes, sand, rocky beaches, and tide pools
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Estuaries
- productive areas where rivers meet the ocean
- provide nursery areas for oysters, crabs, and many fishes
- often bordered by extensive coastal wetlands
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Coral reefs are easily degrades by...
- pollution
- native and introduced predators
- human souvenir hunters
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Freshwater Biomes
- lakes
- ponds
- rivers
- streams
- wetlands
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How are biomes distinguished?
predominant vegetation
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Tropical Forests
- occur in the warm, moist belt along the equator
- most diverse ecosystem on Earth
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Savanna
drier, tropical areasl and some nontropical areas
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Desert
- driest of all terrestrial biomes
- characterized by low and unpredictable rainfall
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Desertification
significant environmental problem
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Chaparral
- shrubland with cool, rainy winters and dry, hot summers
- vegetation is adapted to periodic fires
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Temperate Grasslands
- found in interiors of the contients, where winters are cold
- drought, fires, and grazing animals prevent trees from growing
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Temperate Broadleaf Forests
grow where there is sufficient moisture to support the growth of large trees
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Northern Coniferous Forest/Taiga
- largest terrestrial biome on Earth
- characterized by long, cold winters and short, wet summers
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Artic Tundra
- lies between taiga and permentantly frozen polar regions
- extreme cold, wind, and permafrost (continously frozen soil)
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Population Ecology
- changes in population size
- factors that regulate populations over time
- how and why populations change
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Population
a group of individuals of a single species that occupy the same general area
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Individuals in a population
- rely on the same resources
- influenced by the same environmental factors
- are likely to interact and breed with one another (exchange of gene flow)
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Population dynamics is...
the interaction between biotic and abiotic factors
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What is the cause of variation in population sizes?
- A population increases through birth and immigration
- Death and emigration out of an area decrease the population
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Population Density
number of individuals of a species per unit area or volume
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Dispersion Pattern
the way the individuals of a population are spaced within their area
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Dispersion Pattern
- refers to the way individuals are spaced within their area
- can be: clumped, uniform, or random
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Clumped Pattern
individuals are grouped in patches
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Uniform Pattern
individuals are equally spaced in the environment
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Random Pattern
individuals in a population are spaced in an unpredictable way
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Life Tables
track survivorship over the life span of individuals in a population
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Survivorship Curves
plot the proportion of individuals alive at each age
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Type I
- few offspring
- low mortality until they get old
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Type II
in the middle of I and III
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Type III
- many small offspring
- high mortality rates
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Exponential Growth Model
- rate of population increases under ideal conditions (growth under ideal conditions)
- G=rN
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Logistic Growth Model
- takes into account limiting factors
- limiting factors are environmental factors that restrict population growth - food availability, access to mates in population
- Includes K - carrying capacity - the maximum population a particular environment can sustain
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MOST POPULATIONS FLUCTUATE IN NUMBERS
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Boom-and-bust cycles
- food shortages
- predator-prey interactions
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Maximum sustained yield
Harvest should be done in a way that produces a consistent yield without forcing a population decline
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Age Structure diagram
reveals a population's growth trends
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Ecological Footprint
- helps understand resource avaliability and usage
- US has big ecological footprint
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Conservation Biology
- goal-oriented science
- seeks to counter the Biodiversity crisis
- can focus on one species or protect many species by preserving habitats and ecosystems
- touches all levels of ecology from a single tiger to the forest where it roams
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Scientists are concerned about the ecological changes that underlie biodiversity loss
Ecologists point out that the "services" provided by the biodiversity of ecosystems
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Biodiversity 3 levels
- genetic diversity
- species diversity
- ecosystem diversity - directly related to biodiversity overall
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Endangered Species
- in danger o fextinciton throughout all of a significant portion of its range
- protected by thte Endangered Species Act
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Threatened Species
- likely to become endangered in the forseeable future
- not too much funding provided for threatened species
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Human Alternation of Habitats
- poses the greatest threat to biodiversity
- caused by: agriculture, urban development, forestry, mining, environmental pollution
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Invasive Species
- rank behind habitat destruction as a threat to biodiversity
- compete with native species
- prey on native species
- parasitize native species
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Overexploitation
- third major threat to biodiversity
- overhavesting threatened: rare trees, fish, and bison
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Biological Magnification
- can be caused by pollutants in the food chain
- concentration of pollutant increases as you go up the food chain
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Global Warming is most evident
- in artic from:
- shrinking sea ice
- thinning ice sheets
- melthing permafrost
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Phenotypic Pasticity
- altering phenotype in response to environmental conditions
- within the normal range of genetic expression
- can involve genetic shifts that change a species
- prevents extinction from some species
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Population Fragmentation
- a harmful effect of habitat loss
- splitting and isolation of portions of populations
- can lead to extinctions
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Conservation Biology Priority
- Past Efforts: saving individual species
- Today: biodiversity of ecosystems
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Landscape Ecology
dynamics of a collection of ecosystems
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Biodiversity Hot Spots
- have large number of endangered and threatened species
- have a concentration of endemic species
- hot spot designation favors the most noticable organisms
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Zoned Reserve
- extensive region of land with one or more areas undisturbed by humans
- contribures to sustainable development
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Sustainable Development
- long-term prosperity of human societies and the ecosystem
- provide an economic base for people living there
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Restoration Ecology
- uses ecological principles to restore environments
- replanting native vegetation
- repairing waterways and wetlands
- bioremediation: using organisms to detoxify polluted ecosystems
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