Livingston Public Schools



Biodiversity LabBackgroundA central theme in ecology is biodiversity, which often serves as a measure of the overall health of the ecosystem. Biodiversity refers to the heterogeneity of individuals in a given community, ecosystem, region, country, continent, or in the world. Simply it translates to “variety of life” and is defined as the number (species richness) and variety (different types) of species in a given area. Biodiversity does not indicate species abundance or evenness (the relative distribution of individuals among the species present in the community). Example:Species 1Species 2Species 3Species 4Ecosystem A100101010Ecosystem B100100100100*Both of these ecosystems are biodiverse, meaning they have the same richness or number of different species, however ecosystem A has one dominant species, while ecosystem B has species evenness.As species richness and evenness increase, the measure of biodiversity increases. Declining biodiversity can indicate an ecosystem under environmental stress. Given human species dominant the planet, the concern is for loss of biodiversity. There are many methods that ecologists use to calculate species diversity. In this lab, we will apply the Shannon-Weiner to determine the biodiversity of two sample ecosystems.PurposeTo employ the concept of the null hypothesis in a scientific experiment.To determine the Shannon-Weiner Diversity Index for two ecosystems.To compare and analyze the two ecosystems using the Shannon-Weiner method.Materialsvehicles parked at the school and a calculator with natural log functionIndices of Community DiversityShannon-Weiner Index of DiversityThere are many methods that ecologists use to calculate species diversity. The Shannon-Weiner Diversity Index is a common way of showing that diversity involves not only numbers of different species, but also how well each of these species is represented in different “habitats.” The Shannon-Wiener index (H) indicates the degree of uncertainty of predicting the species of a given individual picked at random from the community. In other words, if the diversity is high, you have a poor chance of correctly predicting the species of the next individual drawn at random.The Shannon-Weiner value “H” can range from 0.0 indicating a community with a single taxon, to a maximum diversity of 4.0. These values have no real meaning by themselves, but can be used to compare two communities or the same community at different times. A large value of H indicates that if you randomly pick in your test area, the odds are the second individual will be different from the first.The equation is: H = - sum(pilnpi)where H = Shannon-Weiner Diversity Indexpi = the ratio of the number of organisms of a species to the total number of organismslnpi = the natural log of pi Examples can be seen on the following page.Example 1, Calculating S-W Index for one ecosystemShannon-Weiner Biodiversity Index, H’Species NameNumber of Organisms of that Speciespi (organism # sum total)ln(pi) (nat log of pi)(pi)ln(pi) pi times ln piSpecies #1Black bear190.11111-2.1972-0.244Species #2Turkey 490.28655-1.2498-0.358Species #3White-tailed Deer 810.47368-0.7472-0.354Species #4Mallard 22? 0.12865-2.0506-0.264Sum Total Organisms ----->36195512445 17100 171H’ = 1.2197Negative sum of all values in column above! 0 < H < 4Example 2, Comparing S-w Indices for different ecosystems: Ecosystem AEcosystem BSpecies 11000Species 1400Species 2100Species 2400Species 3100Species 3400HA = 0.566and HB = 1.099 So, Ecosystem B is more diverse.ProcedureYou need to begin with a good hypothesis. This statement needs to show cause and effect between two aspects of the situation being investigated. The standard hypothesis is an “if…then” statement that connects the two aspects being discussed. Experiments of this nature attempt to agree or disagree with the hypothesis. For this lab we will employ a second type of hypothesis, called the null hypothesis. This is a statement that there is no relationship between the two aspects of the situation under consideration. Experiments of this format are designed to disprove the null hypothesis. Theoretically in science it is easier to disprove something than it is to prove something. The null hypothesis is often the reverse of what the experimenter actually believes; it is put forward to allow the data to contradict it.State your null hypothesis below_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Determine the biodiversity of cars in our parking lots at LHS.Consider each car make (Ford, Honda, Toyota, etc.) as a new pare the biodiversity of:POPULATION A- Senior Parking Lot (on Madonna Dr.) POPULATION B- Faculty Parking Lot (by Cafeteria)Your team will need to count all the various species (Ford, Honda, etc.) in each parking lot to determine the biodiversity index and record all data in the data tables provided. Calculate the Shannon-Weiner Indices for both populations.Answer the analysis questions-161925-4508500-257175190500Analysis Calculate and compare the two indices. Show all of your work! Evaluate your results in light of your null hypothesis.HA- Your calculations from table AHB- Your calculations from table BMy data support/refute my null hypothesis (based on each student individual null hypothesis)Which group, if any, is more diverse? Why do you think this is the case? Diversity = # of species and evenness or abundance. H Values range from 0 to 4. Higher H Value = more biodiversity. More diverse group must be stated with an applicable explanation. Why is biodiversity important? How does biodiversity impact medical, pharmacological and industrial practices? What impacts and implications does biodiversity have on agricultural practices? How does biodiversity affect overall ecosystem health? Antiviral/anticancer properties in new medicines yet discovered. Possible cure for cancerIndustrial uses for chemicals, yet discoveredProtection against disease- Modern agriculture promotes monocultures of a single genotype. Lack of variation could lead to the lack of resistance and disease. Also, healthier soils with varied agriculture.Diversity promotes multiple species with overlapping niches and stability for an ecosystem.Biodiversity is not distributed equally globally. Considering both terrestrial and aquatic biomes, where is the most biodiversity? What happens to biodiversity globally as you go from the equator to the poles (where is there high or low biodiversity, what can you say about climate, are organisms typically specialists or generalists in these regions)?Most diverse Terrestrial- Tropical Rain ForestsMost diverse aquatic- Coral reefsBiodiversity is greatest at the equator and decreases as you approach the poles becauseConsistent climate (temp and precip) at equator = longer growing seasonMore specialists with narrow range of habitats/niche to avoid competition ................
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