DYNAMIC ECOSYSTEM

CHAPTER 8

Learning objectives

1. Understanding the abiotic and biotic components of the environment

Learning outcomes

1. Identify the abiotic and biotic components of an ecosystem

2. Classify biotic components into trophic levels

3. Explain the interactions between biotic components in relation to feeding

4. Explain the interaction between biotic components in relation to competition

What is ecosystem?

An ecosystem is a system formed by the interaction of living organisms with one another & with their environment.

Ecology = the scientific study of the interactions of living organisms with other living organisms & with the physical environment.

Ecosytem of pond

Ecosystem of grassland

Ecosystem of sea

Ecosystem of forest

Our environment consist of:1. Living organisms - biotic

components2. Non-living organisms – abiotic

components

In any ecosystem, abiotic components determine the population size and distribution of the biotic components

Abiotic

component

s

1.pH

value

2. Light

intensity

3.temperatur

e

4.Humidity

5.Topograph

y

6.microclimat

e

1. pH value

Most organisms can survive well in a neutral

or nearly neutral environment Aquatic organisms are sensitive to

theeffects of the pH of water Certain plants prefer acidic soil-

pineapple Certain plants prefer alkaline soil –

coconut plants

2. Light intensity

The varying intensities of sunlight in a forest result in the growth of different types of plants

Tall trees-exposed to high intensity of sunlight

Ferns & vines- survive under the cover of shady trees

Mosses,earthworm,ant –low light intensity of sunlight

3. Temperature

Most living organisms can only tolerate a narrow range of temperature ( 0-45 °C)

Termophilic bacteria can survive in hot spring-extreme temperature

4. Humidity ( amount of water vapour in the air)

The humidity of air affects the rate of water loss by plants & animals

Humidity low-water evaporates from the moist surfaces at a faster rate

Humidity higher at night, lower during the day

Snakes, frogs,mosses-prefer humid area

5. Topography ( bentuk muka bumi)

Is the physical features of the land which concern the altitude, gradient & aspect of a region.

It influences the humidity, temperature & light intensity of an ecosystem

Altitude-higher altitude is associated with lower atmospheric pressure & temperature . So,differents plants grow at differents altitudes.

Gradient-steep slopes result in rapid drainage & run-off. So, the soil layer is thinner & drier- not a suitable habitat for organisms

Aspect-the slopes of mountains facing the direction of wind receive more rain than the slopes shaded from the wind.

6. Microclimate ( climate in a microhabitat)

Includes the humidity, temperature, light intensity & atmospheric conditions in which the organism lives

The biotic components

Producer • Green plants• Use light energy to synthesis organic

substance ( food )

Primary consumers

• Herbivores • Obtain their energy by consuming

producers

Secondary consumers

• Carnivores • Obtain their energy by eating primary

consumers

Tertiary comsumers

• Carnivores• Eating secondary consumers

Decomposer• Bacteria & fungi• Microorganism that break down waste products &

dead bodies of other organisms into simpler substances to be used again by plants

Food chain

A sequence of organisms through which energy is transferred

Starts with a producers & ends with a top consumers

Each organism is the food of the next organism in the chain

Each stage in a food chain is known as a trophic level

Grass

Grasshopper

Frogs

Snakes

Food web

Energy flow in the food web

Interaction between biotic components in relation to feeding

interaction

1.Symbiosis

-commensa

lism -

mutualism-

parasitism

2. Saprophytis

m

3.Pey-

predator

4.Competiti

on

1. Symbiosis

A close relationship between 2 or more different species which live closely together & interact with each other

Can be classified into 3 categories:a) Commensalismb) Mutualismc) Parasitism

a. Commensalism

One species (comensal) benefits while the other ( the host) neither drives any benefits nor is harmed

Example: clown fish & sea anemones, epiphytes (pigeon orchids),staghon fern,bird’s nest fern,Pleurococcus sp.,money plant, remora fish & shark, Protozoa & Cyclops sp., barnacles & crabs/snail.

b. Mutualism

Relationship between 2 species of organisms in which both benefit

Example: lichen (alga n fungus), hermit crabs & sea anemones, Rhizobium sp. Bacteria & legume plant.

c. Parasitism

Relationship between 2 organism in which one organism(the parasites) benefits and other ( the host ) is harmed.

Example: ectoparasites (fleas,lice,barnacles,aphids) & endoparasites (tapeworm,Rafflesia sp.)

2. Saprophytism

Living organisms obtain food from the dead & decaying matter

Example: saprophytic bacteria & fungi ( Mucor sp.), mushrooms,bracket fungus

3. Prey- predator

Relationship where an organsim which is smaller, called prey, is hunted & eaten by a stronger animal, the predator

Predator usually has long canine teeth & sharp claws to hold &kill its prey

Interaction between biotic components in relation to competition

Competition=interaction between organisms living together in a habitat & competing for the same resources that are in limited supply

1 species is more successful than the other

Species which are stronger & have better adaptation are successful species

Species which are weak will either migrate to other areas or die

2 types of competition:

Intraspecific competition

Competition between individuals of the same species

Example: Brophyllum sp.

Interspecific competition

Competition between individuals of different species

Example: Paramecium aurelia & Paramecium caudatum