DIVERSITY


Refers to the number and variety of species that live in
an ecosystem.
Measure of the health of the ecosystem
• Related to the number
of different species
and the number of
individuals of each
species within any
community.
• Describes how the
members of one
species in a given
ecosystem are
closely related
• Variety of ecosystems in a
biosphere
Species
diversity
Ecosystem
diversity
Genetic
diversity
Functional
diversity
• Refers to the way species
behave, obtain food, and
use the natural resources
of an ecosystem
Species richness refers to the number of different
species present in an area.
“The more species present in a sample, the richer the area”
NUMBER OF INDIVIDUALS
FLOWER SPECIES
FIELD A
FIELD B
Gumamela
300
10
Santan
330
50
Rose
370
940
TOTAL
1,000
1,000
Is a measure of diversity , which takes into account
both species richness and an evenness of
abundance among the species present.
Then formula for calculating D is presented as,
D=
𝒏𝒊(𝒏𝒊 −𝟏)
𝑵(𝑵 −𝟏)
D = 1[
𝒏𝒊(𝒏𝒊 −𝟏)
]
𝑵(𝑵 −𝟏)
Where ni = the total number of organisms of each
individual species
N =the total number of organisms of all species
The value of D ranges from 0 to 1
0  infinite diversity
1  no diversity
Therefor, the bigger the value, the lower the
diversity is.
Table 1. Species Composition of Three Different Communities
SPECIES
A
B
COMMUNITY
1
10
11
COMMUNITY
2
72
5
COMMUNITY
3
35
33
C
D
E
F
9
10
8
12
4
3
1
3
32
0
0
0
G
H
I
10
10
11
4
3
2
0
0
0
J
TOTAL
9
100
3
100
0
100
Table 2. Data for Calculation of Simpson’s Diversity Index
Community 1
COMMUNITY 1
SPECIES
ni
ni - 1
ni(ni – 1)
A
B
C
10
11
9
9
10
8
90
110
72
D
E
F
G
10
8
12
10
9
7
11
9
90
56
132
90
H
10
9
90
I
J
11
9
10
8
110
72
TOTAL
N = 100
𝒏𝒊 𝒏𝒊 − 𝟏 = 𝟗𝟏𝟐
𝒏𝒊(𝒏𝒊 −𝟏)
𝑵(𝑵 −𝟏)
D=
𝟗𝟏𝟐
𝑫=
𝟏𝟎𝟎(𝟏𝟎𝟎 − 𝟏)
=
=
𝟗𝟏𝟐
𝟏𝟎𝟎(𝟗𝟗)
𝟗𝟏𝟐
𝟗,𝟗𝟎𝟎
= 0.09
High diversity
• Compute for the values of D for communities 2 and 3, and
write your answer in Table 3.
Table 3. Values for Simpson’s Diversity Index for Communities 1, 2, and 3.
Community
D
Level of Diversity
1
2
3
0.09
Very High
After computation, compare results. What community will have highest
diversity?
What community will have the lowest biodiversity? Why?
Table 2. Data for Calculation of Simpson’s Diversity Index
Community 1
COMMUNITY 2
SPECIES
ni
ni - 1
ni(ni – 1)
A
B
C
72
5
4
71
4
3
5, 112
D
E
F
G
3
1
3
4
2
0
2
3
6
12
H
3
2
6
I
J
2
3
1
2
2
TOTAL
N = 100
20
12
0
6
6
𝒏𝒊 𝒏𝒊 − 𝟏 = 𝟓, 𝟏𝟖𝟐
𝒏𝒊(𝒏𝒊 −𝟏)
𝑵(𝑵 −𝟏)
D=
𝟓, 𝟏𝟖𝟐
𝟏𝟎𝟎(𝟏𝟎𝟎 − 𝟏)
𝑫=
=
𝟓,𝟏𝟖𝟐
𝟏𝟎𝟎(𝟗𝟗)
=
𝟓,𝟏𝟖𝟐
𝟗,𝟗𝟎𝟎
= 0.52
Low diversity
Table 2. Data for Calculation of Simpson’s Diversity Index
Community 1
COMMUNITY 3
SPECIES
ni
ni - 1
ni(ni – 1)
A
B
C
35
33
32
34
32
31
1, 190
1, 056
992
D
E
F
G
0
0
0
0
-1
-1
-1
-1
0
0
0
0
H
0
-1
0
I
J
0
0
-1
-1
0
0
TOTAL
N = 100
D=
𝑫=
𝒏𝒊(𝒏𝒊 −𝟏)
𝑵(𝑵 −𝟏)
𝟑, 𝟐𝟑𝟖
𝟏𝟎𝟎(𝟏𝟎𝟎 − 𝟏)
𝟑,𝟐𝟑𝟖
=
𝟏𝟎𝟎(𝟗𝟗)
=
𝟑,𝟐𝟑𝟖
𝟗,𝟗𝟎𝟎
= 0.33
high diversity
𝒏𝒊 𝒏𝒊 − 𝟏 = 𝟑, 𝟐𝟑𝟖
• Compute for the values of D for communities 2 and 3, and
write your answer in Table 3.
Table 3. Values for Simpson’s Diversity Index for Communities 1, 2, and 3.
Community
D
Level of Diversity
1
0.09
Very High
2
0.52
Low
3
0.33
High
After computation, compare results. What community will have highest
diversity?
What community will have the lowest biodiversity? Why?

https://www.youtube.com/watch?v=HA3xNMJnFu
o


Biodiversity is always threatened as a result of
human activities and natural phenomena.
It disturb the stability of an ecosystem and affect
living things in their habitat.

Happens
when a
tremendo
us change
has
happened
in the area
that it can
no longer
support
wildlife
Actual destruction
Fragmentation
Degradation
Actual
destruction
•ecosystem
is converted
into
subdivision
or park
•Kaingin
System
•Happens
when
something
interrupts
Degradation
the
equilibrium
of the
ecosystem
Fragmentation
•When
roads
and
dams are
created


Refers to the
plants, animals,
or microbes that
move into new
environment in
several ways.
The new species
can be parasite
or predator




Toxic synthetic
chemicals
heavy metals
Found whether in
air or water
Affect the species
abundance and
can lead to their
extinction
• Eutrophication
- Overabundance of
nutrients or nutrient
pollution
Bioaccumulation
- Accumulation of
toxic chemicals in
the tissues of an
organism.

Climate Change
-is the threat because
living things live in
temperature range and
if there is a shift of
temperature it will be
difficult or even
impossible to survive.
• Global
warming
• Melting of
ice
• Bleaching
and dying
coral reefs
• Extreme
storms
• Flooding
• Drought
Endangered species are those threatened to
extinction

Answer Assessment letter A ( number 1 to 5),
page 255-256
IF THESE THREATS CAN BE OVERCOME BY STABLE
ECOSYSTEM, THEN THERE WILL BE AN INCREASE IN
POPULATION.
POPULATION…
Means the group of the same species interacting with each
other
RANDOM DISTRIBUTION
2. CLUMPING DISTRIBUTION
- Uncommon pattern
- When individuals aggregate in
- The position of each
patches.
individual is independent of
- This group formation is for
other individual
protection against their
- Example flower established
predator.
windblown seeds
3. UNIFORM DISTRIBUTION
- When individuals are evenly
distributed
- This is influence by
territoriality or social
interactions.
1.



Population size refers to population density
Population density is equal to the number of individuals per
unit area
Population growth is based on the four fundamental factors:
BIRTH RATE, DEATH RATE, IMMIGRATION, AND EMIGRATION
• BIRTH RATE –number
of individuals being
born
• IMMIGRATION – is
moving in of an
individual in a
certain place
• DEATH RATE –
number of
individuals that dies
• EMIGRATION – is moving
out of the individual in a
certain place.
Population growth = (BIRTH RATE + IMMIGRATION ) – (DEATH RATE +
Emigration )

LIMITING FACTORS

CARRYING CAPACITY



What are the threats to Biodiversity?
What is population ?
What are the three patterns in population
distribution?