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2.3 Measuring Biotic Components

2.3 Measuring Biotic Components. What is classification?. Science of grouping organisms based on their physical characteristics. What characteristics do we use?. Structures (morphology) Functions (physiology) Biochemistry Genetics. Why do we classify?. Identify organisms

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2.3 Measuring Biotic Components

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  1. 2.3 Measuring Biotic Components

  2. What is classification? • Science of grouping organisms based on their physical characteristics.

  3. What characteristics do we use? • Structures (morphology) • Functions (physiology) • Biochemistry • Genetics

  4. Why do we classify? • Identify organisms • Compare organisms • Identify relationships among organisms • Communicate with others (universal language) • Identify evolutionary relationships

  5. Why do we classify? • What am I? • Firefly • Lightning bug • Glow Fly • Blinkie • Golden Sparkler • Moon bug • Glühwürmchen • Luciérnaga • Luciole • We all have different names for the same organism…this is a problem for communication.

  6. From Aristotle to Linneaus • Aristotle (Greek philosopher) • (384-322 B.C) • First System of Classification • 1. Plants • Based on stem type • 2. Animals • Land, air or water

  7. From Aristotle to Linneaus • CarolusLinneaus (Sweedish botanist) • (1707-1778) • Came up with modern classification system • Used binomial nomenclature (2 word naming system) • This two word name is called a scientific name • Composed of the genus name followed by the species name

  8. Scientific Names • Either written in italics or underlined • Genus is always capitalized and species is always lowercase • Based on Latin • Examples: • Cat: Felix domesticus • Mosquito: Colexpipens • Human: Homo sapien

  9. Funny Scientific Names • Agra vation (a beetle) • Colon rectum (another beetle) • Bahumbugi (a snail) • Aha ha ( a wasp) • Lalapalusa (a wasp) • Leonardo davinci (a moth) • Abracadabra (a clam) • Gelaebaen, Gelaebelae, Gelae donut, Gelae fish, and Gelaerol (all types of fungus beetles) • Villa manillae, Piezakake and Reissaroni  (bee flies)

  10. Dichotomous Keys • A series of yes/no questions about an organisms structure • Used to identify new and unknown organisms

  11. Example of Dichotomous Key • 1a. Hair Present…………..Class Mammalia • 1b. Hair Absent……………Go to statement 2

  12. Example of Dichotomous Key • 2a. Feathers present…………..Class Aves • 2b. Feathers absent…………….Go to statement 3 • 3a. Jaw Present…………………..Go to statement 4 • 3b. Jaw Absent……………………Class Agnatha

  13. Example of Dichotomous Key • 4a. Paired fins present……………Go to 5 • 4b. Paired fins absent…………….Go to 6

  14. Example of Dichotomous Key • 6a. Skin scales present………………Class Reptilia • 6b. Skin scales absent……………….Class Ampibia

  15. Estimating Populations of Organisms • We estimate populations because it would take way too long to count every living thing in a given ecosystem. • We can estimate populations of plants or animals • Random Sampling: All organisms must have an equal chance of being captured.

  16. Estimating Populations of Animals • Lincoln index (capture-mark-release-recapture) n1 x n2 N = n3 • N = Total number of population • n1 = Number of animals first (mark all of them) • n2= Number of animals captured in second sample • n3= Number of marked animals in second sample Ex. 40 mice were caught, marked (tail tattoo) and released. Later, 10 mice were recaptured, 4 of which had tattoo marks.

  17. Lincoln Index

  18. Lincoln Index Assumptions • The marked animals are not affected (neither in behavior nor life expectancy). • The marked animals are completely mixed in the population. • The probability of capturing a marked animal is the same as that of capturing any member of the population. • Sampling time intervals must be small in relation to the total time of experiment of organisms life span. • The population is closed (no immigration and emigration) • No births or deaths in the period between sampling.

  19. Estimating Populations of Plants • Quadrat Estimation • Population Density- The number of plants within the given area of the quadrat (m2) • Percentage Coverage- How much of the area of a quadrat is covered by plants? • Frequency- How often does a plant occur in each quadrat? • Acacia senegalensis was present in 47 of 92 quadrats, for a frequency of 51%

  20. Calculate Population Density What is the population density of species x ? What is the population density of species Y? What is the population density of species Z? Quadrat 1= 0.5m2

  21. Calculate Percentage Coverage What is the percentage of plant coverage in this quadrat? Quadrat 1= 0.5m2

  22. Percentage Frequency Quadrat 1 What is the frequency of species X? What about species V? Quadrat 2 Quadrat 3

  23. Other Methods of Estimation(Plants) • Sampling – Take a sample from one area and assume the organisms are evenly spread out through the area. • Biomass (dry weight) of living tissue • We use dry weight because water is non-living and needs to be excluded • Ex. 10 ferns were found in a 100m2 area. How many ferns would be in 1000m2 field in the same ecosystem?

  24. What is diversity? • Diversity is the variety of life • Diversity is a combination of two components • Evenness: The number individuals of each species present in a sample • Richness: The total number of different species in a sample

  25. How Can We Know Diversity? Use the Simpsons diversity index below D = ____________N (N-1)_______________ n1(n1−1) + n2(n2 −1) + n3(n3 −1) +…nk(nk −1) D = Diversity N = Total number of organisms of all species n = number of individuals of a particular species ***The higher the D value the more diverse the sample is!!!!!

  26. Example Data Calculations

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