An introduction to Ecology

Introduction:

 The term of Ecology was first introduced by Ernest Haeckel (1834 – 1914)
 This term is derived from Latin words:
 Oikos means home
 Logos means to study/knowledge
 Generally, Ecology is defined as a study deals with inter relationship between living organisms and their environment.
 This shows that there are relationship between ecology and other disciplines within Biological Sciences and other Sciences.

 Other disciplines related to ecology:
– Morphology - Chemistry
– Physiology - Geology
– Genetics - Physics
– Evolution - Meterology
– Molecular Biology
– Developmental Biology
– Behavioral study
 With the above disciplines, it is expected that the scientists can improve their understanding on the relationship between living organisms and their environment.

 Therefore, ecology is scientific study that incorporate hypothetico-deductive approach
 In this case it uses observation and experiments to test hypothetical explanations of ecological phenomena
 Therefore this discipline is a challenging that are because of its multidisciplinary nature


Components of Ecology

 Biotic Components
– This includes all living organisms located in a certain area
– In this area a living species becomes the environment of other species
– This living organisms can be:
• All types of bacteria
• Fungi
• Microalgae
• Moses
• Ferm
• Invertebrates
• Vertebrates
• Human
• Terrestrial plants
• Etc.
 Within an area mentioned above, these living organisms possess their specific way to interact each other and to their abiotic components to gain energy
– Example: green plants conduct photosynthetic process by using CO2 and H2O (abiotic components) to produce biomass (as producer)
– Biomass of plants will subsequently be consumed by herbivores (level 1 consumers)
– Herbivores will be eaten by carnivores (Level 2 consumers)
– All dead plants and animals will finally be decomposed by microorganisms

Abiotic components

o All other components excluding biotic components
o These include physical and chemical components
o These two components determine the characteristic of an environment where the living organisms occur
o These physicochemical components are:
– Temperature
– Light
– Water
– Air
– Humidity
– Minerals
– Soils
o All of these interact each other to form the characteristic of the environment
o Temperature
– This is the degree of heat energy
– Important parameter that determines the rate of biochemical reactions within the body of organisms
– Important factor for living organisms in the reproduction process.
• This is related to migration of many species of birds when they need to reproduce
o Light
– The main source is Solar radiation
– Consists of several wavelength of light
– Three component of light required by organisms; the wavelength, light intensity, and period of exposure
o Water
– Water is found in the solid, liquid, and gas forms
– App. 80 to 90% of the body component of living organism consists of water
– The role of water to living organisms:
• As solvent in the metabolic pathways
• To maintain osmotic pressure of cells
• To avoid cells from dryness
o Hymidity
– This means water content of air or soils
– This is a very important factor for living organisms in order to survive
– The humidity required by organisms varied depends on the species of those organisms.
o Air
– Air consists of several types of gas
• Nitrogen (78.9%) as a protein component
• Oxygen (20.93%) as a component in respiration process
• Carbo dioxide (0.03%) as a component in the photosynthesis
• Other gases (…%)
o Minerals
– These include ions of nitrogen, phosphorous, Sulphur, Calcium, Sodium (Na), etc.
– These determine the soil characteristics
– Example: the content of Na+ and Cl- determine the salinity of soils
o Soils
– Soil is formed as a result of rocks decomposition
– This process is due to climatic changes plus decomposition of organic materials
– Fertile soils is needed by plants and other organisms to live
– Soils have their specific characteristics, texture, and mineral content that determine their fertility.


Inter dependency between living organisms and their environment

 Each group of organisms (either the same or different species) will occupy a suitable area for them to live (called the habitat)
 Each species in this habitat will interact each other
 These species also interact with their abiotic environment
 An example of this interdependency can be found in a damp soil habitat
– One possible population found in this habitat is earthworms (Pheretima sp.)
– This species can live there, because this habitat provides them with suitable temperature, moisture content, and organic content of the soil (suitable physicochemical components)
– Besides this earthworms, other living organisms, such as millipedes, bacteria, fungi, fern, ants, and Mosses can also be found in this habitat (this is the biotic components of this habitat
– How these component interact (especially the biotic components) will be discussed later