Ecological Studies 2
Objectives:
● To treat and analyse the results of sampling methods.
● Use sampling methods to determine the most
❖
❖
❖
❖
❖
❖
Dominant
Abundant
Common
Frequent
Occasional
Rare Species
Treatment of Results from
sampling methods
From Quadrats
A scalemap should be drawn showing the positions of the quadrats thrown.
The results of the quadrat can be used to obtain:
● Species density: The average number of individuals of each species per m2
● Species Cover: the percentage of the ground covered by a species; used if
individual organisms were difficult to count
● Species frequency: The percentage of quadrats in which a particular species
is found.
These results can then be recorded in tables and charts
Example
Histograms showing a. Species density and b. Species cover
Terms to remember
❖ Dominant: The species that predominates in an ecological community,
particularly when they are most numerous or has the greatest effect on the
environment
❖ Abundant: the number of individuals per species
❖ Common: describe the population status of a species whether there is a
large number of organisms in a specific species or not
❖ Frequent: The species most frequently found in every sample obtained
❖ Occasional: The species least frequently found in every sample obtained
❖ Rare Species: A group of organisms that are rarely encountered
Line Transects
Information from line transects could be shown on profile diagrams
One group of students uses a 1 m2 quadrat to determine the distribution of three plant
species in the area behind lhe mangroves. The results are shown in Table 1.
1.
Complete the table by calculating the total population, species density and species frequency for each species.
TABLE 1: RESULTS FROM QUADRAT THROWS
Plant
Organisms
Quadrat Numbers
1
2
3
4
5
6
7
8
9
10
Small
flowering
shrub
5
2
3
2
2
1
2
1
3
1
Grass growing
in clumps
4
2
3
2
0
1
2
4
0
0
Succulent
plants
10
10 12
15
20
25
15
22
5
18
Total
Population
of species
Species
Density
Species
Frequency
2. Complete the following table and answer the questions on the next slide
SPECIES
1
A
B
QUADRAT SIZE: 1m²
QUADRAT NUMBER (No. of individuals)
2
3
4
5
6
7
2
20
%
25%
C
2
3
3
4
3
D
10
%
50
%
5%
45
%
20
%
8
9
6
2
30
%
5%
5
2
2
0
20
%
10
%
30
%
10
Total
Populati
on
10
20
%
0
Species
Density
(Individual
s per m2)
1
80%
24
190
%
Species
Frequency
%
30
50
2.4
Spec
ies
Cove
r
8%
80
80
19
%
Which species is the Most
1.
2.
3.
4.
5.
Dominant?
Abundant?
Frequent?
Occasional
Rare?
Outline how the quadrat is to obtain the results in the table
Type your answer here
Abiotic
Factors in
Ecological
Study
Objectives:
● Identify the abiotic
elements associated
with an ecosystem
● Determine the
Relationship between
the distribution of
species to abiotic
factors
EUTROPHICATION???
Importance of Abiotic Factors
Climate and Vegetation
How to measure Climatic factors
Temperature: Thermometer
Humidity: Wetand Dry bulb thermometer
Light Intensity: Photographic Light Meter
Rainfall: Rain Guage
Wind Speed :Anemometer
Wind direction: Wind Vane
Edaphic Factors
Objectives:
● Define Soil
● Describe the process of soil
formation
● Identify the components of soil
● Identify the types of soil
● Describe the characteristics of
each type of soil
Components of Soil and Their
Importance
Soil Profile
Particles of
clay soil are
tightly packed
Particles are large
and spaced
CONSTANTS:
Amount of water
added.
Amount of soil
EVALUATION
Create a blank document and answer the following questions:
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●
●
●
●
●
●
Name FOUR abiotic factors that influence the distribution and survival of living organisms.
List FOUR reasons why soil is important to plants.
Why are sandy soils better aerated than clay soils?
What is humus and how does it get into the soil?
List THREE advantages of having plenty of humus in a soil.
What are the problems of trying to cultivate a clay soil?
How may a sandy soil be improved?