AN INTRODUCTION TO BASIC AQUATIC ECOLOGY

PART I. BASIC CONCEPTS AND PRINCIPLES OF ECOLOGY

1. IntroductionA. What is ecology ?B. The Biological SpectrumC. What is ecosystem ?

A. What is ecology?

Ecology is defined as the study of the relationship between organisms and their environment.

The word ecology derived from the Greek oikos, meaning 'house' or "place to live."

Literally, ecology is the study of organisms "at home.“ Ernest Haeckel 1866

"Ecology is defined as the study of the relation of organisms or groups of organisms to their environment, or the science of the interrelations between living organisms and their environment.“

"Ecology is environmental biology."

The economy of nature.

“The first law of ecology is that everything is related to everything.”Barry Commoner

B. The Biological Spectrum.

Biotic : Gene - Cells - Organs - Organisms - Populations - Communities+ ------------------------------------------------------------------------------------------------------

Abiotic: Matter <<<<<<<<||||||||||||||||||||||||||||>>>>>>>> Energy= ------------------------------------------------------------------------------------------------------

Biosystems Genetic Cell Organ Organismic Population EcosystemsSystems Systems Systems Systems Systems

The community in the ecological sense (biotic community) includes all of the populations occupying a given area. The community and the non-living (abiotic) environment functiontogether as an ecological system or ecosystem.

Biosphere or ecosphere encompassed the earth's living organisms interacting with the physical environment as a whole. The biosphere is to maintain a steady-state system intermediate in the flow of energy between the high energy input of the sun and the thermal sink of space.

C. What is Ecosystem ?

Any unit that includes all of the organisms (i.e. the "community") in a given area interactingwith the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and materials cycles (i.e, exchange of materials between living and non-living parts within the system is an ecological system or ecosystem.

Basic definition= "An ecological community (bioceonosis, biocenose) together with itsenvironment (biotope), functioning as a unit."

Trophic (nourishment & feeding habits) of an ecosystem has two components.Autotrophic = self-nourishing like plants (nourished from light energy).Heterotrophic = other-nourishing like animals (nourished from consuming other).

Abiotic = Nonliving: The abiotic factors of the environment include light, temperature, and atmospheric gases.

1. Inorganic substances (Carbon C, Nitrogen N, Carbon dioxide CO2, H2O) in material cycles.

2. Organic compounds (protein, carbohydrates, lipids, ) that link biotic and abiotic.3. Climate regime (temperature and other physical factors)

Biotic = Of or having to do with life or living organisms.1. Producers, autotrophic organisms like plants that are able to manufacture

food from simple inorganic substances.2. Macroconsumers (phagotrophs, phago=eat) heterotrophic (hetero=other)

organisms mainly animals which ingest other organic matters or organisms. Not able to manufacture own food).

3. Microconsumers (Saprotrophs, sapro=to decompose) mainly bacteria, fungi which break down the complex compounds of dead organisms.

The biotic components are the biomass (=living weight).

Biomass = The total mass of living matter within a given unit of environmental area.

A scenario of a pond as an ecosystem.

1. Abiotic substances = Water, carbon dioxide, oxygen, calcium, nitrogen & phosphorus salts, amino & humic acids, etc.

2. Producer organisms = a. Rooted and large floating plants usually growing in shallow waterb. Minute floating plants like algae, phytoplankton (phyto=plants,

plankton=floating) distributed through out the pond as deep as light penetrates.

3. Macroconsumer organisms = Animals, insect larvae, crustacea and fish.a. Primary Macroconsumers (herbivores) that feed directly

on plants like zooplankton (animal plankton) and benthos (=The collection of organisms living on or in sea or lake bottoms.)

b. Secondary Macroconsumers (carnivores) like predaciousinsects and fishes.

4. Saprotrophic organisms = The aquatic bacteria, flagellates and fungi mostly along mud-water interface on pond bottom where bodies of plants and animals accumulate. A minority of them are pathogenic whereby they will attack living organisms and cause diseases but the great majority begin to attack only after the organism dies as the pond detritus (=a product of disintegration, Latin deterere, to wear away.)