Transcript 2.3.1 Taxonomy/ Classifciation

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
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2.
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6.
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 CoverageHow much of the area of a
quadrat is covered by plants?
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
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?
Quadrat 1= 0.5m2
What is the population density of
species Z?
X
X
X
W
W
W
X
X
W
X
W
X
X
X
X
W
X
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X
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z
W
W
Y
Calculate Percentage Coverage
What is the percentage of plant
coverage in this quadrat?
Quadrat 1= 0.5m2
X
W
X
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X
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X
X
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X
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Y
Percentage Frequency
Quadrat 1
What is the frequency
of species X?
What about species V?
X
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X
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Z
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V
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Y
Quadrat 2
Quadrat 3
Z
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Y
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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
7
species 5
7
0
Diversity
3.27