CHAPTER 9

ECOSYSTEM
 9.1
COMMUNITY
&
ECOSYSTEM
 TERMS TO KNOW!!
HABITAT SPECIES POPULATION COMMUNITY
The natural A group of similar A group of The populations of
surrounding or organisms, able to organisms of the all organisms form
the living place interbreed and same species different species
of an organisms produce offsprings which live in the living in the same
same habitat habitat whilst
interacting with
each other
 ECOSYSTEM
A few communities that live together in a habitat and interact with each
other including non-living components (abiotic)
 NICHE
The role of an organism in an ecosystem
which includes its behaviour and interactions
with biotic and abiotic components in the
surroundings of its habitat

ecological species
niche niche
The role of a The way in which a species
species in its interacts with biotic and
surroundings abiotic components within
its suroundings
 ECOSYSTEM

BIOTIC COMPONENTS ABIOTIC COMPONENTS

All living organisms interact with each All non-living elements including their physical
other such as humans, animals and and chemical characteristics that can affect an
plants organisms in an ecosystem

producers pH value
consumers temperature
decomposers light intensity
topography
microclimate
air humidity
 pH
pH influences the growth and distribution of living organisms
Most organisms are capable living in neutral or almost neutral (pH 6-7)
Soil is a habitat for millions of worms and microorganisms (bacteria, fungi, protozoa)
The pH of soil is important for suitability of worms, microorganisms and plants to living

A little change in pH value

disrupts the activities of

microorganisms that live in soil

and reduces its fertilty

Coconut trees
Pineapple prefer

acidic soil grow well in

(pH < 7)
alkaline Worms can live in neutral range
(pH > 7) (pH 6-8)
 Temperature
Organisms have specific adaptive characteristic to live within their different temperature ranges
A little change in temperature causes a reduction in the metabolic rate of organisms
The enzymes that catalyse physiological responses are sensitive towards temperature changes

Most animal can live Polar bears live in Foxes can live in

within the Tundra with desert with

temperature range of temperature temperature

20°C - 40°C of -14°C above 45°C

 Light Intensity
Light and duration of sunlight received can strongly influence the distribution of organisms
Most green plants prefer high light intensity to carry out photosynthesis

Taller plants in tropical Only small plants (such as Coniferous forests have with

rainforests that are ferns) can grow under canopy temperature climate lower

exposed to high light (which provide low light density of plants due to low

intensity form a canopy intensity) light intensity

 Topography
Topography is the physical characteristics on the surface of the Earth which
include altitude, gradient & aspect
It determines humidity, temperature & light intensity in an ecosystem

ALTITUDE GRADIENT ASPECT

Steeper mountain slopes Aspect refers to the direction in
Altitude
are easily eroded due to which wind blows and the rays of

Relative humidity swift water movement sunlight

Atmospheric pressure
The soil layer becomes A mountain slope which faces the

thinner and drier sea has denser plants compared to

Oxygen content

This area has less growth the one facing towards the land
Plants at different levels of
of plants except for This slope also gains more rainfall
altitudes are different in types,
some short, thorny shrubs distribution
sizes and density
with small and pointed The slope that receives more
Ex: Pine trees grow at higher
leaves sunlight is denser with plants
alt. are smaller in size

compared to meranti trees

 Microclimate
Microclimate refers to the climate condition of a small area which is different from the
surrounding area
It also refers to climate in a micro-habitat such as one below a rock or in a hole.
It can take place under the rocks, or beneath the shades of bigger plants of the forest canopy

Temperature

Humidity Light Intensity

Heat Balance
Microclimate Atmospheric
depends on Pressure

Water Ability of Soil to

Evaporation Retain Water

Milipedes
 Air Humidity
Air humidity is the quantity of water vapour in the air which affects the distributions of
organisms in a habitat
There are more organisms occupying areas of high humidity than in dry areas (low humidity)
Low air humidity increases water loss in a stoma through transpiration (chap. 2)
This situation enhances the absorption of water and mineral salts from the soil
Transpiration also provides a cooling effect, therefore plants can maintain optimum temperature
for enzyme action
BIO EXPLORATION
A rhinoceros has a big body & its TSA/V

is small. Therefore, the rate of heat

released from the skin is low.

Transpiration rate increases On hot days, the rhinoceros often wallow

as the air humidity decreases in muddy water. When mud dries up, it

forms a layer which protects the

rhinoceros skin from sun heat.
AUTOTROPHIC & HETEROTROPHIC NUTRITION
NUTRITION
Nutrition is a way for an organism to obtain
nutrients and energy from the food for its life

Self Eater Others Eater

Differentiation
AUTOTROPH HETEROTROPH
Organism that Photosynthesis Digestion Organism which
synthesises its own process process cannot synthesise its
food from non-organic own food but
materials by using light Plants Animal depends on a
energy and chemical Some Human various external
energy bacteria Fungi sources
 TYPES OF NUTRITION
AUTOTROPH HETEROTROPH
PHOTOTROPH CHEMOAUTOTROPH SAPROPHYTE HOLOZOIC PARASITE
Organisms that Bacteria which Saprophytic Organisms that eat Organisms that
synthesise complex synthesise organic organisms which solid organic absorb nutrients
organic compounds coumpounds using obtain food in the substances (other from the hosts
from together with light energy released from form of organic organisms), then
(photosynthesis) oxidation of inorganic materials from digested and
substances (ammonia) dead and decaying absorbed into the
through chemosynthesis organic substances body.

Digestion occurs Humans and most

outside the body of animals are holozoic
an organisms Tapeworm
before the nutrients
are absorbed

Nitrobacter sp.
 TROPHIC LEVELS

Producer Primary consumer Secondary consumer

Microorganisms
decompose waste
substances into
simpler organic
substances

Tertiary consumer Decomposer

 TROPHIC LEVELS
4rd TROPHIC LEVEL
carnivore animal which eats secondary consumer
Tertiary consumer

3rd TROPHIC LEVEL

carnivore animal
Secondary consumer

2nd TROPHIC LEVEL

herbivore animal
Primary consumer

Producer 1st TROPHIC LEVEL

synthesis organic substance from inorganic
substances photosynthesis
 Energy flow in food chain
A food chain is the sequence of energy transfer
from one trophic level to another trophic level

In a food chain:

It starts with the producer and ends with either a secondary consumer/tertiary consumer
Organisms feed on organisms from the previous trophic level
Energy is transferred from the consumed organisms to the feeding organisms
Energy is transferred between trophic levels when an organism eats other organisms grow
which it gains its energy. This energy is transferred to the organism after it has digested
and assimilated the food to form new substances in the body.

10% energy 10% energy 10% energy

transfer transfer transfer
 However, most animals feed on more than one type of organisms
These circumstances will create more food chain, at once it called food web

In a food web:

It shows the feeding

relationships in a
community

It consists of several
food chains

Organisms in all food

chains rely on each
other in feeding
aspects
 ECOLOGICAL PYRAMIDS
PYRAMID OF NUMBERS PYRAMID OF BIOMASS
Shows the number of

se e
organisms at every trophic

s
inc crea
Tertiary consumer
level in a food chain 400 kg/km^2

re a
de

Dr
ym
nis ms
rga nis
ms

ass
Secondary consumer
2100 kg/km^2
f o orga

de
Shows the total

cre
g ni

csa
Siz er of

biomass per unit area

d ne

a se
d ne
Primary consumer
csa
eo

of all organisms in
mb

g ni

s
21000 kg/km^2
every trophic level
Nu

Producer

Biomass is measured
21000000 kg/km^2 by using dry mass
PYRAMID OF ENERGY The food energy may be stored in
Demonstrates the total body tissues, or transferred into
energy which is present environment in form of excrement
in an ecosystem (faeces) or discharged as urine

When food
Energy source
molecules are
Light Chemical Tertiary consumer
0.1% decomposed for

rs
(photosynthesis) respiration and

sfe

90
This chemical other reactions,

ra n

%e
energy (only 10%) yt Secondary consumer some energy is

ne
1%
erg

will be transferred released into the

rgy
environment
en

g ni

csa
to next trophic

los
d ne
10 %

through heat

d ne
level

s
Primary consumer
csa

g ni
10%
90% of the
Producer
energy is
dissipated
100%
 PARASITSM
INTERACTION An interaction that
SAPROPHYTISM benefits one
SYMBIOSIS
organism but
An interaction in which Occurs when different harms the other
an organism gets its species that live together, organism
food from dead interact with each other
organic materials

MUTUALISME COMMENSALISM
An interaction that gives An interaction that
benefits to both organisms provides benefits to
only organism without
causing any harm to
the other organism
 INTERACTION
PREDATION COMPETITION
An interaction Occurs when
involving an organisms in a
organism (predator) habitat compete
that eats another in order to get
organism (prey) basic needs such
as food, water,
light and mates

INTERSPECIFIC COMPETITION INTRASPECIFIC COMPETITION

Happens among organisms Happens among organisms of
of the same species different species
 Exposed to waves and water tides
Abiotic Components

Mangrove trees Germination of

Soft, silted
and muddy soil
are tropical seedlings in
that lacks
plants which tidal area Abiotic aeration
found in Components
estuaries of Mangrove
Exposed to very Ecosystem Exposed to
strong light strong wind
intensities blows
Estuaries is a
place where
the sea and
river meets

Soil with high salt content as well as very low content

of dissolved oxygen in water
Biotic components Silvered leaf monkey

Stork Proboscis monkey

Mushroom Biotic Components Snake

of Mangrove
Ecosystem

Mangrove trees Mudskipper

Crab Horseshoe crab

 Leaves

Pneumatophore
Seeds
Roots

Adaptation Features
of Mangrove Trees

Buttress
Prop roots
Roots
 Leaves Prevent escaping water vapour from air currents
and decreasing water loss from the leaf.
Mangrove leaves have thick cuticles and sunken stomata which can reduce the rate of
transpiration
Theses leaves have succulent leaves that can store water and special structure known as
hydathode to eliminate excess salt
Mature leaves can store salt, which will fall off when the concentration of salt stored is too high

Thick cuticles
can be seen by
their thick waxy
appearance

Excess salt
 Pneumatophore roots
Pneumatophore roots are short root projections from the soil surface for aeration in water-
submerged areas
The root allows the gas exchange between the submerged root and atmosphere through lenticels
Example: Avicennia sp.

Young pneumatophore roots

 Prop roots
Prop roots branch out from the lower part of the stem of a mangrove tree
The roots are firmly planted in the soil to support the tree to overcome strong winds and waves
Example: Rhizophora sp.
Incoming strong winds

Incoming strong waves

 Buttress roots
Buttress roots are a type of roots with a thick structure that can add in widening the base of a tree
The roots provide support to the tree that grows on soft soil which borders with solid land
Example: Bruguiera sp.
 Seeds
Viviparous seeds germinate and grow when they are still on the parent plant
This enables fallen seedlings to stick into the muddy soil and will not be uprooted by waves
 COLONISATION & SUCCESION
An ecosystem can change After a long period of time, Pioneer species is a species
Human activity (like mining)
due to natural phenomena this deserted area starts to that begins to colonise an
can cause organisms to die
(volcano eruption, have inhabitants known as area where there are no
or migrate to other habitats
earthquakes, draught) Pioneer Species other living things

Plants start to
conquer an
uninhabited area,
breed and form
colonies in that A few species of dominant
area plants in a habitat are
gradually being replaced by
other species called successor
 COASTAL ZONE
Coastal zone is the area that is most exposed to big waves
This zone is dominated by pioneer species [ex: Avicennia sp. & Sonneratia sp.]
An enlarged root system and pneumatophores help the trees to trap mud and organic
substances which are brought by high tides
Mud accumulation slowly begins and as a result, the soil becomes higher denser
Rhizophora sp. succeeds and replaces the pioneer species

Sonneratia sp. (mangrove apple)

Avicennia sp. (api-api trees)

Rhizophora sp. (bakau minyak tree)
 MIDDLE ZONE
Middle zone is situated along the river, closer to the estuaries
An area inhabited by Rhizophora sp. plants that have tangled prop roots. These roots can trap
twigs and mud which are washed away and block the flow of water
The trapped mud causes sedimentation to occur much faster
The river bank becomes higher and drier because less seawater overflows during high tides
The soil becomes less suitable for the growth of Rhizophora sp. Instead it is more suitable for
Bruguiera sp.
Bruguiera sp. succeeds and replaces Rhizophora sp.

Bruguiera sp. (tumu merah trees)

 INLAND ZONE

Inland zone is situated further into the land

The soil becomes higher, harder and only flows with seawater during high tides
The area is inhabited by Bruguiera sp. which have buttress roots to trap move mud and slit
Sedimentation process forms a new swamp that projects out towards the sea
The one-time shore gets further away from the sea and the ground changes into a land which
is suitable for land trees such as Nypa fruticans and Pandanus sp.
The land trees succeed and replace Bruguiera sp.

Pandanus sp.

Nypa fruticans
 Importance of
Mangrove Ecosystem
PROTECTION ZONE
 Importance of
Mangrove Ecosystem
FISHERY RESOURCES
 Importance of
Mangrove Ecosystem
FORESTRY RESOURCES
 Importance of
Mangrove Ecosystem
FOOD AND MEDICINE RESOURCES
 9.2
POPULATION
ECOLOGY
 POPULATION ECOLOGY POPULATION DISTRIBUTION
A branch of ecology which How the organisms of
studies the interaction of a same species are able to
population with its spread out in a habitat
surroundings

What are the factors affecting the population distribution?

 mperature
Te

Water
Salt Con
ral te
ne
i

nt
M

Factors for Plants

Soil pH Light
The optimum temperature for plant growth is between T
25°C - 30°C E
High temperature can cause enzyme to denatured.
M
Biochemical processes in plants are disrupted and they:
+ stunt the growth of plants P
+ increase the rate of water evaporation by transpiration E
+ slow the rate of photosynthesis R
Low temperatures reduce the activities of A
enzymes which slow down the biochemical reaction
T
U
R
E
 W
Water is needed for enzyme activities, photosynthesis,
transport and support in herbaceous plants A
Dry regions such as a desert and tundra areas as at the T
poles have low population distribution and also low E
density of plants R

L
I Light is very important for the process of
G photosynthesis in plants
H Areas which receive little light have a
lower number of plants
T
 The pH of soil is important for nutrient absorption by the roots
Soil in which the pH is either too acidic or too alkaline will soil
cause lower absorption of nutrients by plants ph
The growth of plants will be disrupted due to lack of nutrients

Salt content affects the absorption of water through

osmosis by the roots
High salt content in soil will cause plants to lose water
MINERAl through osmosis
salt Minerals are needed for the production of proteins, enzymes,
content nucleotides, vitamins and other compounds
As an example, phosphorus is used to form phospholipids
(in the formation of cell membrane)
 Water mpertaure
Te

Factors for Animals

eding Site d Supply

Bre Foo
 TEMPERATURE
Areas which exposed to high
temperatures in a habitat are less
inhabited by certain animals such as
worms and snails
WATER

Animals are concentrated in areas that

have enough water sources for drinking
and cooling in the body
 Breeding site
A safe and suitable breeding site is needed
by animals to raise their offsprings
FOOD SUPPLY

Food is important for survival because

animals are heterotrophs which depend
on plants and other animals for food
POPULAR DISTRIBUTION
ESTIMATION OF ORGANISM POPULATION SIZE
2 Important Factors for
Studying Population Ecology

POPULATION SIZE POPULATION DENSITY

The number of organisms The number of individuals of a
present in a population species per unit area of a habitat

The population size in an area can be estimated by a random sampling technique

when the studied area is large and difficult to obtain data.
A sample which represents the area is taken to give an estimation of the abudance
and the distribution pattern of certain organisms that inhabit the area
 QUADRAT SAMPLING TECHNIQUE
Estimate the population size of
land plants or animals which are
inactive or move slowly

A quadrat is a square-framed
structure which is made of wood,
iron or plastic

Normally, a quadrat is subdivided

into a few parts of the same size to Quadrat size depends on:
estimate the coverage percentage 1. Type and size of organism
of any species. 2. Density of research area
3. Distribution of organism in the research area
This technique can estimate the frequency,
frequency, density & coverage of
any plant species
 CAPTURE-MARK-RELEASE-RECAPTURE TECHNIQUE
Estimate the population size of organisms such as foxes, sharks, snails, millipedes,
insects and butterflies which can move freely in the studied area
THANKS FOR YOUR KIND
ATTENTION