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Chapter 5 – Evolution of Biodiversity

Chapter 5 – Evolution of Biodiversity. Module 14 The Biodiversity of Earth. It is difficult to estimate the number of species on Earth.

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Chapter 5 – Evolution of Biodiversity

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  1. Chapter 5 – Evolution of Biodiversity Module 14 The Biodiversity of Earth

  2. It is difficult to estimate the number of species on Earth Species – group of organisms that is distinct from other groups in terms of size, shape, behavior, or biochemical properties and can interbreed with other individuals in its group to produce viable or fertile offspring.

  3. Pond Lawn

  4. Common measure of Biodiversity = # of species in any given place What about the # of species on Earth? (easy or challenging?

  5. It is challenging because; - hard to find - nocturnal species - live in inaccessible locations (deep ocean) - microscopic - species are uniformly distributed

  6. Unknown Diversity 2M species : identified

  7. Sample method of estimating the # of species • Fumigate a tree • Collected dead insects • Sort them out by species (ex: beetle) • Count the # of each species in one (1) tree and multiplied it with the # of tropical trees. Result: 8M (canopy alone) 30M total estimate (including the ones in the bottom ground.

  8. We can measure biodiversity in terms of Species Richness and Evenness • Two (2) measures for species diversity at local or regional scales. Species richness = the number of species in a given area such as a pond, canopy of a tree, or a plot of grassland. = is used by scientists to give an approximate sense of the biodiversity of a particular place.

  9. Species evenness = is the relative proportion of individuals within the different species in a location. = it tells us whether a particular ecosystem is dominated by one species or whether all of its species have similar abundances.

  10. Species richness and evenness • Decline after a human disturbance • Gives scientists a baseline that they can use to determine how much that ecosystem has changed.

  11. Evolutionary relationship among species can be illustrated using a phylogeny Phylogeny = the branching pattern of evolutionary relationships. = can be describes using a diagram known as phylogenetic tree (cladogram).

  12. Scientists used the following to measure similarity • Morphology • Behavior • Genetics • * The more similar traits of two (2) species, the more closely related they are

  13. Measuring Biodiversity (Richness and Evenness) a) Simpson’s Diversity Index b) Shannon’s Diversity Index Where: 0 = no diversity 1 = infinite diversity D = diversity index N = total number of organisms of all species found in the sample Σ = the sum of n = number of individuals of a particular species in the sample where: H = the Shannon diversity index Pi = fraction of the entire population made up of species i S = numbers of species encountered ∑ = sum from species 1 to species S Note: The power to which the base e (e = 2.718281828.......) must be raised to obtain a number is called the natural logarithm (ln) of the number.

  14. Simpson’s Diversity Index

  15. Simpson’s Diversity Index

  16. b) Shannon’s Diversity Index Area 1 Calculate the diversity of Area 2 in your WS and compare the 2 areas.

  17. b) Shannon’s Diversity Index Area 1 Calculate the diversity of Area 2 in your WS and compare the 2 areas.

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