Test 3 Quiz 2 Flashcards
Define community
A group of interacting plants and animals living in a given area in the same period of time
What two things make up community diversity?
species richness & evenness
Richness= the amount of species in an environment
Evenness= measure of the relative abundance number of each species (abundance is # of individuals from that species divided by total # of individuals)
What are the two markers of community productivity?
Biomass: Weight of living materials, dry weight per unit area
Diversity: Richness and evenness
Define standing crop biomass
Total amount of biomass per unit area in a given period of time
Describe the Shannon Index of Biodiversity. Does it consider richness, evenness, or both?
Find the proportion of each species, find natural log of proportion, then multiply proportion by natural log, sum for all species and multiply by -1 (bigger number wins).
Considers both richness and evenness
Describe the coefficient of community. Does it consider richness, evenness, or both?
For comparison of two communities → Multiply 2 by the number of species common to both, then divide by the sum of the number of species in both communities (higher is better).
Considers only richness.
Describe percentage similarity. Does it consider richness, evenness, or both?
Find all the species common to both. Sum up the lowest percentages for each species.Ex: Community 1 has 13% abundance of species A and 45% abundance of species B and Community 2 has 23% abundance of species A and 39% abundance of species B. Percentage similarity is equal to 13+39
Considers relative abundance (evenness) only.
Define dominance in relation to communities
The dominant species in a community can be determined by biomass or abundance. Each method may yield different results.
Define keystone species
A species that has disproportionate influence over community structure and functions. Removal will negatively affect many other species, causing a great loss in diversity.
Give an example of a keystone species providing habitat
The coral Oculina arbuscula provides a habitat for over 300 species of invertebrates, many of which complete most of their life cycle inside the coral.
Give an example of a keystone species feeding behavior
African elephants are destructive feeders that feed mainly on browse. They reduce tree and shrub density, favoring growth and reproduction of grasses.
Define edge
The place where two or more vegetation communities meet (distinct border)
Define ecotone
The place where two communities meet and interact (gradual transition)
Define edge effect
The variety and abundance of species is often better in and around ecotones and edges
Define ecological island
An isolated habitat or area
State the MacArthur-Wilson Island Equilibrium Theory
he number of species of a given taxon established on an (ecological) island represents a dynamic equilibrium between the immigration rate of new colonizing species and the extinction rate of previously established colonizing species
What are the factors determining immigration and extinction rate? How do the rates change as number of species increases?
size of island and distance from continent
Immigration- Start high, end low
Extinction- Start low, end high
As Number of Species Increases
Define succession
Temporal variation in community structure at a given location
Define and describe early/initial successional species (include selection type)
The initial colonists or pioneer species
Often Have: High growth rates, smaller size, high degree of dispersal and colonization, high rates of per capita population growth, r-selection
Define and describe late successional species (include selection type)
Arrive later
Often Have: Longer lifespans, larger size, lower rates of dispersal and colonization, lower rates of per capita population growth, k-selection
Define primary succession
Occurs at a location that was not previously occupied by a community; a newly exposed surface
Define secondary succession
Occurs at a location that was previously occupied by a community and then underwent a disturbance that removed all or part of the existing community
-can include a natural disaster or a farmer abandoning his field
Define autogenic
Self-generated environmental change; the result of the presence and activities of organisms within the community. Example: Changing vertical light profile through succession.
Define allogenic
Environmental change governed by physical (not biological) processes (Ex: temperature declines over elevation)
Describe the change in species diversity in succession
Diversity does not always increase over time
Define a climax forest
A stable end forest that perpetuates itself under prevailing environmental conditions. Needs a fire to rejuvenate its ecological functions.
Define crown fire
Spread quickly, moving through the branches
Define ground fire
Start from the ground up, burn through everything
What are some lumbering-associated social and economical issues?
Use of the income to benefit locals
Impact on nutrients
Road construction
Potential erosion related to lumber transportation
The great ice sheet the _________ shrunk dramatically between ___________ during the _____________ exposing land in Canada and the Upper US
The great ice sheet the Laurentian shrunk dramatically between 18 TYA and 8 TYA, during the Wisconsin Glaciation Stage
What are the four genera of trees that started to spread after the ice sheet melted in the US/Canada?
Spruce, White Pine, Oak, and Maple
Terrestrial ecosystems are classified by _________
dominant plant life-forms
Aquatic ecosystems are classified by ________________
salinity
Define watershed and first order stream
Watershed: Entire region drained by a waterway into a lake or reservoir. Can be divided into five or more orders of streams.
First Order Stream: Headwater stream without tributaries
Streams can be divided into …………
fast and slow
Define riffle zones
Areas where water flows quickly and there is a high oxygen content sna lots of life. They are the major sites of primary production.
Describe the area between riffle zones
where decomposition occurs, reducing CO2 to HCO3- which maintains the water’s stability
What are some factors that affect the diversity of streams?
nutrients, temperature, light, depth, topography
What are the four groups of stream invertebrates?
Shredders/Collectors: Process detrital materials (coarse and fine particulate organics, respectively)
Grazers: Feed on algae coating on stones
Gougers: Burrow into waterlogged trunks
Define eutrophication
The nutrient enrichment of a body of water, excess of nitrogen and phosphorous
State the Clean Water Act (1972)
To restore and maintain the chemical, physical, and biological integrity of the nation’s waters by preventing point and nonpoint pollution sources, providing assistance to publicly owned treatment works for the improvement of the wastewater treatment, and maintaining the integrity of wetlands
Describe point vs nonpoint source pollution
Point: Comes from a single, identifiable source or point. Effects usually remain local, Examples include sewage pipes, smokestacks, and oil spills.
Nonpoint: Source that cannot be traced back to a single thing, more diffuse and non concentrated around a particular point or source. Examples include CO2 in atmosphere
What is the National Pollutant Discharge and Elimination System (NPDES)?
A permit program for point source pollution
What is Total Maximum Daily Load (TMDL)?
A value of the maximum amount of a pollutant that a body of water can receive while still meeting water quality standards
What is DO?
The amount of dissolved oxygen in a river or stream, < .5 mg/L anoxic, .5-2 hypoxic, <3 stressful, >5 healthy
What is BOD?
Biological Oxygen Demand: The amount of dissolved oxygen needed by aerobic microbes to break down organic material present in a given water sample at a certain temperature over a specific time period.
What is BOD5?
5-Day Test (BOD5): Measure the change in oxygen content in a water sample
Describe the nitrogen cycle
The process of nitrogen transformation including N2 in the air, N in organic matter, and NH4+/NO3- in soil and water
Define ammonification
The transformation of organic N into NH4+ in the soil or water
Define nitrification
The oxidation of NH4+ in the soil or water to NO2-, then to NO3- in the soil or water by bacteria of the genus nitrosomona or nitrobacter
Define denitrification
The reduction of NO3- in the soil to N2 in the air by anaerobic bacteria
Define nitrogen-fixation
The process of converting N2 in the air to organic N, usually by lightning
Describe the phosphorous cycle
The process of phosphorous transformation including P in organic matter and PO4-3 in rock or natural phosphate deposits
Define mineralization related to phosphorous
The process of P from dead organic matter becoming phosphate in rock or in deposits
Tell me about plasticizers. Talk about where they are found, how they are introduced into the environment, and their effects
Plasticizers are common in both southern and northern MO streams. They come from air transportation via rain. Many of them have estrogen-like properties. For example, in the 1990s people in the UK found fish with bisexual organs such as ovotestes.
What are fish enclosures for? How much control to researchers have?
Fish enclosures are used so that researchers can connect a particular location with the effects of a compounds. They prevent fish from moving up and down streams and can test the development of individuals under real-world conditions.
Describe a mesocosm study
In a mesocosm study, tubs filled with stream water are connected to the stream and filled with plants and animals so that researchers can study their interactions. There is more control in the mesocosm than the enclosure studies. They allow testing of the community effect of interactions under stressful conditions.
Describe a microcosm study
In a microcosm study, water is brought to the lab and placed in tanks with algae, plants, and lab surrogate animals. Amphibians are good cause they feel the effects of changes in both habitats. There is even more control, and scientists are able to change one condition at a time (such as the dilution of stream water). These can find dose-response conditions and threshold effects.
What is the significance of the hydrological cycle?
Freshwater, saltwater, and terrestrial ecosystems are not independent
What are the three ways lakes and ponds are formed?
Glacial Depressions
Shifts in the Earth’s Crust
Dams (beaver and human made)
Define thermocline
A layer in a thermally stratified body of water in which temperature changes rapidly relative to the remainder of the body
Describe the summer layer of epilimnion in lakes/ponds
Warm, oxygen-rich upper layer of water
Describe the summer layer of Metalimnion in lakes/ponds
Zone with a significant drop in temperature
Describe the summer layer of Hypolimnion in lakes/ponds
Cold, oxygen-poor layer of water with no plants and no light
Define overturn
A transition of oxygen and temperature from a heterogeneous distribution to a homogeneous distribution throughout a lake/pond in late fall and early spring
Describe how overturn occurs in late fall
Cold, dense water sinks from the surface until the temperature becomes uniform. Nutrients and O2 are evenly distributed.
Describe how overturn occurs in early spring
Top layer is still colder relative to lower levels (due to sheltering from wind), so newly synthesized nutrients sink and O2 at the top layer mixes with other layers
Define oligotrophic and include the type of trees near those lakes/ponds
Nutrient-poor
Conifers
Define mesotrophic
Moderate nutrient-rich
Define eutrophic and include the types of trees near those lakes/ponds
Very nutrient-rich
Deciduous and Farmland
Define hypertrophic
Eutrophic and our fault, even higher
What are the two ways of dealing with hypertrophic lakes/ponds? Describe them
Use CaCl2 or CaSO4 to kill plants
Does not remove nutrients
You can also remove algae and plants
Better, will take years to take effect
What is the limiting factor for photosynthesis in freshwater? What about oceans?
Phosphorous is the limiting factor of photosynthesis in freshwater, nitrogen is limiting factor in ocean
