Biodiversity “Biodiversity is the variation of life forms within a given ecosystem, biome, or for the entire Earth. Biodiversity is often used as a measure of the health of biological systems. The biodiversity found on Earth today consists of many millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution.

Both communities have 10 species. Which is most diverse and why? Shultz et al. (1999)

Seashell Biodiversity Lab Purpose: To learn how to use the Shannon Diversity Index to calculate species diversity and understand what the Shannon diversity index represents Background: Biodiveristy is… The Shannon Diversity Index is used to determine which communities are the most diverse and is a function of both species richness and eveness. Species richness is a measure of how many different species there are in a community and species eveness indicates how evenly they are distributed. Question: Which population of snails has the highest diversity? Hypothesis: Prcedure: Count each type of shell in each population and enter the data into your data table. Calculate the Shannon Diversity Index for each population.

Shannon Biodiversity Index H’ = -∑ (pi)(ln pi) (pi = species proportion) ni The number of individuals in species i; the abundance of species i. S The number of species. Also called species richness. N The total number of all individuals pi The relative abundance of each species, calculated as the proportion of individuals (ni)of a given species to the total number of individuals in the community (N):

Calculating Biodiversity Species # individuals (ni ) Species proportion (pi) (divide number of each species by total number of individuals = ni /N) Ln pi (use your calculator!) (pi)(ln pi) (hint (multiply the previous 2 columns for each species) A B C D Etc. Total # of individuals N = Species Richness = This column should sum to 1.0 Sum this column, then take the inverse (change the sign) This is H’

Shannon Index Data Table Species # individuals (ni ) Species proportion (pi) (divide number of each species by total number of individuals = ni /N) ln pi (use your calculator!) (pi)(ln pi) (hint (multiply the previous 2 columns for each species) A B C D E Total# of individuals N Species Richness: This column should sum to 1.0 Sum this column, then take the inverse (change the sign) This is H’

Shannon Biodiversity Index The Shannon Diversity index is a mathematical equation used to measure species diversity As the index value (H) increases, species diversity increases What factors increase species diversity?

Factors influencing biodiversity measurements Species Richness: Species Evenness: