Environmental Systems

1. Environmental Systems Measuring Biotic and Abiotic Components of a System 2.1.1, 2.3.1-2.3.5, 2.7.1-2.7.3

2. Biotic vs Abiotic (ie physical) components of an ecosystem • Biotic = • Examples: • Abiotic = • Examples

3. List the variable abiotic (physical) factors of an ecosystem • Terrestrial • Marine • Freshwater

4. Describe & Evaluate methods for measuring abiotic (physical) components • Precipitation: rain gauge • Temperature: thermometer • pH: pH strip; pH probe • wind speed: aerovanes • Dissolved Oxygen: DO Probe or chemical test • Salinity: Hydrometer

5. Describe and use methods for estimating abundance of organisms • Quadrat - A quadrat is a frame of any shape that can be placed over vegetation so that species can be listed or counted, and population density, percent frequency and percent cover can be estimated. = For non-mobile organisms • Capture-Mark-Release-Recapture (Lincoln Index) = For mobile organisms

6. Quadrat System of Counting Example

8. Capture-Mark-Release-Recapture (Lincoln Index) • N= the estimated population (what you are looking for) • T1: total organisms you caught and marked in 1st sample • T2: total organisms you captured in 2nd sample • M: the number that were marked in the 2nd sample. (meaning they have been recaptured) • N = T1 x T2 M Example… So, do you have a larger population if you have a large or small “M”? Why?

9. Evaluate techniques • Cap/Mark/Recap: • Only works with a static population…..does this occur in nature? • Marked individuals are more noticeable to predators • Losing their marks by molting, rain, etc • Quadrats: • Limit accuracy by amount of money you have to spend on counters. • Less counters or smaller quadrats mean less accuracy. • Placement of quadrats can cause results to be skewed.

10. Describe and evaluate a method of estimating biomass of trophic levels in a terrestrial community • Biomass - estimate of dryweight in g/m2 of an organism. • Method?

11. Diversity • Three types: Habitat, species, genetic • 2 components: • 1. Richness = # of different species in an area • 2. Evenness = a measure of relative abundance of each species in an area. (number of organisms of each type of specie) • A community that is dominated by one or two species is less diverse than one that has several different species with a similar abundance, even if they have the same richness amount. • Ex?

12. Apply Simpson’s diversity index • A measure of species richness of an area. • A high value suggests a stable, climax community. • A low value could suggest pollution, early stages of succession or agricultural management………Why?

13. Calculation • D= Simpson’s Diversity Index • N = TOTAL # of organisms of all species found. • n = number of individuals of a particular species. • D = N(N-1) Σ[n(n-1)]

14. Example • SpeciesN • A 3 • B 4 • C 2 • D 2 • E 4 • Total = N = 15 • N(N-1) = 15(15-1) = 210 (210 is your top number!) • n(n-1) • 6 • 12 • 2 • 2 • 12 • Σ[n(n-1)] = 34 (34 is your bottom number!)

15. Example Con’t • Simpson’s Index: D = N(N-1) Σ[n(n-1)] D = 15(14) = 210 34 34 D = 6.17 • Is this area diverse? • Here is the problem: • You CAN’T tell from this equation. • All you can do is tell relative diversity when compared to another area/Diversity number • ie: This area would be less diverse than an area whose Simpson’s Index number is 10. • Only used for comparative purposes

16. Describe and evaluate methods for measuring changes in abiotic and biotic components over time • Rainfall = rain gauge • Temp = thermometer • Species diversity = quadrats or mark and recapture and then Simpson’s Diversity Index • Species abundance = quadrats or mark and recapture • All of these stats would be taken over a set amount of time………..mutiple data sets (at least 2....when?)

17. Environmental Gradient • What is a gradient? • Therefore an environmental gradient is a change in abiotic or biotic factors over an area. • Examples of where you can see this? • How should you measure this?

20. Describe and evaluate methods for measuring changes in abiotic and biotic components of an ecosystem due to specific human activity • YOUR LABS DO THIS!! • Examples of human effects and how to measure them? • Could also include satellite images and maps.

21. Describe the use of Environmental Impact Assessments • An EIA is a government report prepared before a development project that will change the use of land (in the planning process). • Ex: major new road networks, airports, building power stations, dams, quarrying, planting a forest, converting fields to a golf course, large-scale housing projects, etc. • The EIA weighs up the relative advantages and disadvantages of the development. • It will try to quantify how the abiotic and biotic factors would change if the development occurs. • Therefore, a baseline study is necessary first....what the environment is like now. • The EIA will forecast both negative and positive impacts on the natural environment and human populations (if the development might have an effect on human health or a community’s economy).

22. Evaluate EIA’s • EIA’s measure the social and environmental costs of the development and tries to translate these into monetary values. • Ex: number of jobs provided, net profit of the development, land degradation, habitat loss, pollution, human health, etc. • What issues can there be with many of these assessments?

23. Construct simple keys and use published keys for identification of terrestrial organisms (Dichotomous Keys) • Homework: • Find pictures of or draw 8 organisms and print them out. • Make a dichotomous tree and then a key • On a third sheet of paper, print the pictures out again and make an answer key.