12.0 ECOLOGY

Contents:

Introduction to ecology Ecosystem concept Energy flow Biogeochemical cycles Biodiversity: conservation and

management

12.1 INTRODUCTION TO ECOLOGY

Objective Define basic terminologies in

ecology

Ecology :study of the interactions among organisms, between organisms and their physical environment.

Introduction to ecology

Basic term in ecology

Niche Habitat Organism Population Community Ecosystem Biome Biosphere

Niche

Niche is the status or role of an organism in its habitat/environment.

Eg : Feeding behaviours aphid and caterpillar aphid suck the plant saps

caterpillar eats the leaf.

Habitat The place in which an

organism lives.

Examples : streams, ponds, rivers and lakes.

Organism

systems working together with far greater precision and complexity make up the complex livingorganism.

~ Individuals of the same type of organism living together are called a population

THE ORGANIZATION OF LIFE

All the different species that live in a place are called a community

Eg: forest community

A community and the physical environment in which it lives is called ecosystem.

THE ORGANIZATION OF LIFE

oMajor terrestrial ecosystems, called biomes

oClimate controlled group of plants & animals in the wide area

THE ORGANIZATION OF LIFE

.

Examples of biome include desert, tropical rain forests and tundra.

THE ORGANIZATION OF LIFE

Biome

All of the communities of living things on Earth are organized into the biosphere.

THE ORGANIZATION OF LIFE

12.2 ECOSYSTEM CONCEPTObjectives At the end of this lesson, students should be able to :

• Explain ecosystem concept.

• Explain the components of the ecosystem with examples:

i. biotic components

ii.abiotic components

iii. interaction between biotic components

iv. interaction between biotic and abiotic components.

• Describe the following ecosystem structures;

i) lake ecosystem

ii)Terrestrial ecosystem of tropical rainforest

Definition according to Odum (1969)

The basic functional unit of nature including both organisms and their non-living environment

interacting with the other and influencing each other’s

11.3 THE ECOSYSTEM CONCEPT

Levels of ecological organization

BiosphereBiome

Ecosystem ecology Community study

Population

Organism biodiversity

The components of the ecosystem

BIOTIC COMPONENTS

ABIOTIC COMPONENTS

- living organisms.

- non living components

INTERACTIONS BETWEEN BIOTIC; BETWEEN BIOTIC

AND ABIOTIC

BIOTIC COMPONENT

1. Autotroph/producer

2. Heterotroph/consumer

3. Decomposers

Autotroph (producers) – manufacture organic food from inorganic substances from environment.

In terrestrial ecosystems- green plantsIn aquatic ecosystems – phytoplankton (algae & blue green bacteria).

1) Autotroph/producer

- Organisms that cannot synthesize their own food from inorganic materials.

- Obtain organic nutrients by....?

2) Heterotroph/consumer

Herbivores

Carnivores

Omnivores

Detritivores

Heterotroph can be divided into four type of organisms

Primary consumers :An animal that feeds directly on plants or algae.

A) HERBIVORE

Secondary/tertiary consumers:Predators - An animal that feeds on other animal; flesh-eater.Scavengers – which usually eat what is left by the predators (eg : vultures)

B) CARNIVORE (meat eaters)

An animal that eats a variety of plant and animal material

C) OMNIVORE

An organism (such as an earthworm or crab) Feed; small fragments of dead organisms waste matter of animals and plants.

Also called detritus feeder.

D) DETRITIVORE

Decomposers are microorganisms – mainly fungi & bacteria.

Also called saprophyte.

Secrete digestive enzymes onto dead or waste material & absorb the products.

3) DECOMPOSER

bacteria

Fungi

Competition

Predation

Symbiosis

Interactions between biotic components

(i) COMPETITION

occurs when two or more individuals require the same resource that is in short supply.

Can occur among members of the same species or different species.

COMPETITION

same speciessame species; ; intraspecificintraspecific competitioncompetition

different different species;species; interspecificinterspecific competition.competition.

(iii) PREDATION community interaction

where one species (predators), eats another (prey).

Includes ; animal-

interactions and animal-plant interactions

SYMBIOTIC

3 COMMON TYPES OF SYMBIOTIC RELATIONSHIP ARE :

a) Mutualism

b) Parasitism

c) Commensalisms

Symbiosis:

Individual of 2 or more sp. live in direct with one another Harmful, helpful, neutral

a) MUTUALISM Biological interaction

between two organisms, where each individual derives benefit to each other.

E.g : Hummingbird drinking from Dianthus , lichen.

a) MUTUALISM

Anemones provide the fish with protection from predators (which cannot tolerate the stings of the anemone's tentacles) and the fish defend the anemones against butterfly fish which eat anemones

b) PARASITISME

Close association between two living organisms of different species which beneficial to one (parasite) & harmful to other (host).

b) PARASITISME Can divided in 2

types : 1. Endoparasites 2. Ectoparasites

c) Commensalisme The relationship between

two species; one species got benefit from the relationship & the second species is unaffected by it.

Eg : host tree & epiphytes

Eg :Barnacles

c) Commensalisme

Interaction between biotic & abiotic components.

Abiotic components are the nonliving chemical and physical factors to which an organism is exposed.

Abiotic components are :

Atmosphere – made up of gases that envelop the Earth.

Hydrosphere – waters of the Earth, liquid and frozen water.

Lithosphere – the soil and sediments of the Earth’s