1. EVPP 110 Lab Rain Alternative Population Simulation 1-2 Diversity of Life 12
Week of October 29th 2018
Version 1 1.
1/13/2019 9:56:19 AM

3. Population Growth
Population: group of individuals of same species inhabiting same area at same time.
When resources are unlimited, populations tend to grow exponentially.
Also known as density-independent growth, because the number of offspring produced by each female is not dependent on the density of individuals in the population.

4. Density-Independent Growth
Nt+1 = λ Nt
Where: Nt+1 = # of individuals in the next generation. Nt = # of individuals in the current generation. λ = # of new individuals per old individual.

5. If the population is doubling, λ = 2; if tripling, λ = 3.
If the population increases by 50%, λ = 1.5
Density-independent growth can also be represented by:
e = base of natural logarithm
r = intrinsic rate of increase
Thus, λ = er
If λ = 2, r=0.693.
Nt = N0 * ert

6. Limits to growth
Exponential growth cannot continue indefinitely, because resources are not unlimited.
Limits set in and growth slows to logistic or density-dependent growth.
Eventually, organisms will hit a carrying capacity (K).
K = number of individuals that can survive in a given area indefinitely.

7. Populus Software Download from
You may need the Java Runtime Environment

10. Diversity of Life – Activity 12 – Trees

11. Photo © Student Government (2016)
Trees provide valuable ecosystem services:
Reduce stormwater runoff.
Help control erosion.
Removes pollutants from air
NO2, SO2, O3, CO, particulate matter.
Absorbs atmospheric carbon.
Aids in energy conservation.
Provide food and shelter for other organisms.
Photo © Student Government (2016)

12. Importance of Tree Diversity
Diversity varies by forest type.
Affects diversity of other organisms in ecosystem.
Dictates type of ecosystem services a particular type of forest can perform.

13. Circle versus tree trunk
Cross-section of tree trunk is roughly “circular” in shape.
Circumference (C)
distance around perimeter of circle
C =  D (or, C = 2  r)
Diameter (D)
Distance from edge to edge of circle, passing through center.
D = C /  (or, D = 2 r)
Radius (r)
distance from center of circle to edge of circle
r = ½ D
Area (A)
A =  r2

14. Determining the diameter of a tree trunk while it is still standing/uncut:
Can’t be done directly, so…
Measure circumference and do the math, e.g.:
Circumference = 150cm
C /  = D
150cm/  = D
47.75cm = D
D = 47.75cm

15. Quadrat 1 Table 12.1 Use simulated tree quadrat data.
WO - 36
RM - 42
DW = 8
DW - 12
TT = 24
WP = 22
AH = 6
RM = Red Maple
DW = Dogwood
WO = White Oak
AH = American holly
WP = White Pine
TT = Tulip Tree
Use simulated tree quadrat data.
Each circle represents a tree, letter represents species and number represents DBH in cm.
Table 12.1
Tree #
Tree species
DBH (cm)
DBH (m)
Basal Area (m2) 1
White oak 36
0.36
 ((½(0.36))2 =0.102 2
Red maple 42
0.42
0.435 3
Dogwood (1) 8
0.08
0.016

16. Population Density #/m2
Table Total number of trees (abundance), population density (#/m2), total basal area (m2), and % basal area by tree species for group quadrat
Tree
Species
Abundance (#)
Population Density #/m2
Total Basal
Area (m2 )
% Basal
Area
White oak 2
2/98 = 0.02
2.272
(2.272/2.473) x 100 = 91.87
Red maple 1
0.01
0.159
6.43
Black gum
0.042
1.70
Abundance of each species = # individuals of each species.
Population density of each species = abundance / area of quadrat.
Quadrat = 7m x 14m = 98m2
Total basal area per species = sum of all basal areas of one tree species.
Percent of the total basal area represented by each species = (total basal area for a species / total basal area in quadrat) x 100.

17. % basal area of dominant species
Table Dominant tree species, number of trees of dominant species, total number of all trees, % dominant tree and % total basal area for dominant species by group
Group #
Dominant tree species
# trees of dominant
species
# trees (all species)
% dominant species
% basal area of dominant species
Ex.
White oak 2 3
(2/3) x 100 = 66.67
91.87 1 4 5 6
Determine the dominant (most abundant) tree in your quadrat and record the results for all groups.

18. Weekly Data Sheet pages
What’s Due
Weekly Data Sheet pages
Weekly Write-Up pages
Activity 1
521, 525, 529
Activity 2
539, 543, 547, 551,
555, 559, 563
Activity 12
203, 207
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