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 Compare organisms Identify relationships among organisms Communicate with others (universal language) Identify evolutionary relationships

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.

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

From Aristotle to Linneaus Carolus Linneaus (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

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: Colex pipens Human: Homo sapien

Funny Scientific Names Agra vation (a beetle) Colon rectum (another beetle) Ba humbugi (a snail) Aha ha ( a wasp) Lalapa lusa (a wasp) Leonardo davinci (a moth) Abra cadabra (a clam) Gelae baen, Gelae belae, Gelae donut, Gelae fish, and Gelae rol (all types of fungus beetles) Villa manillae, Pieza kake and Reissa roni  (bee flies)

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

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

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

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

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

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.

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.

Lincoln Index

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.

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%

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 X W z Y

Calculate Percentage Coverage What is the percentage of plant coverage in this quadrat? Quadrat 1= 0.5m2 X W Y

Percentage Frequency What is the frequency of species X? Quadrat 1 What is the frequency of species X? What about species V? X W V Z Y Quadrat 2 Quadrat 3 X W Z Y Z W X Y

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?

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

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!!!!!

Example Data Calculations   Abundance of Organism Ecosystem A Ecosystem B species 1 3 5 species 2 7 4 species 3 26 12 species 4 9 species 5 Diversity 3.27