 Ecology is the branch of biology that deals with the study of interaction between organism and their environment Source:

 Greek origin  OIKOS = household  LOGOS = study of…  Study of the “house/environment” in which we live.

 non-living components in the environment…  light  water  wind  nutrients in soil  heat  solar radiation  atmosphere, etc.

 Plants  Animals  microorganisms in soil, etc.

 For non-living (abiotic) living(biotic)  Climatology Animal  Hydrology Taxonomy  Oceanography Physiology  Physics Mathematics  Chemistry studies)  Geology  Soil analysis, etc.

 views each locate as an integrated whole of interdependent parts that function as a unit

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 An ecosystem may be defined as a dynamic system which includes biotic and abiotic environment influencing the properties of each other and both necessary for the maintanance of life.

 Biotic components(living parts).  Abiotic components(non-living parts).

 The biotic components of an ecosystem can be classified according to their mode of energy acquisition.  In this type of classification, there are:  Autotrophs and Heterotrophs  Organisms that produce their own food from an energy source, such as the sun, and inorganic compounds. e.g herbivores.  Organisms that consume other organisms as a food source. e.g carnivores,omnivores.

 ABIOTIC components:  Solar energy provides practically all the energy for ecosystems.  Inorganic substances, e.g., sulfur, boron, tend to cycle through ecosystems.  Organic compounds, such as proteins, carbohydrates, lipids, and other complex molecules, form a link between biotic and abiotic components of the system.

 There are basically two types of ecosystems; 1)Terrestrial. 2)Aquatic. Terrestrial ecosystems:  Terrestrial ecosystems are found everywhere apart from water bodies. They are broadly classified into: 1)Forest Ecosystem. 2) Desert Ecosystem. 3) Grassland Ecosystem.

1)Forest Ecosystem:  These are the ecosystems where abundance of flora (plants) is seen and they have a large number of organisms living in relatively small areas. 2) Desert Ecosystem:  Desert ecosystems are found in regions receiving an annual rainfall of less than 25cm.  Flora and fauna are very poorly developed and scarce.

3) Grassland Ecosystem:  Grasslands are found in both temperate and tropical regions.  This area mainly comprises of grasses with very little amount of shrubs and trees.  Main vegetation is grasses, and plants are belonging to composite family.

Aquatic eco-system:  An aquatic ecosystem is an ecosystem located in a body of water.  It comprises aquatic fauna, flora and the properties of water too. There are two types of aquatic ecosystems, 1)Marine and 2) freshwater.

1)Marine ecosystem:  Marine ecosystems are the largest ecosystems.  The water in Marine ecosystems has salts and minerals.  In marine ecosystems brown algae,Jelly fish corals, cephalopods,, and sharks are found.

2)Freshwater Ecosystem:  There are three basic types of freshwater ecosystems  Lentic: Still or slow-moving water like pools, ponds, and lakes.  Lotic: Fast-moving water like streams and rivers.  Wetlands: Places where the soil is saturated or inundated for at least some time.

 Reception of radiant energy of sun.  Manufacture of organic materials from inorganic ones by producers.  Consumption of producers by consumers and further elaboration of consumed materials  After the death of producers & consumers complex organic compounds are degraded by decomposer.

Begins with the SUN Photosynthesis 6CO 2 + 6H 2 O + sunlight & chlorophyll  C6H 12 O 6 + 6O 2

The chemical reaction by which green plants use water and carbon dioxide and light from the sun to make glucose. ENERGY is stored in glucose; glucose is stored as starch

 CELLULAR RESPIRATION is the chemical reaction that releases the energy in glucose. 6O 2 + C 6 H 12 O 6 --> 6H 2 O + 6CO 2 + energy The energy that is not used by producers & can be passed to consumers.

 CONSUMERS. Organisms that cannot make their own energy are called consumers.

 Primary consumers.  Secondary consumers.  Tertiary consumers. Consumers that eat producers to get energy are first order or primary consumers E.g herbivores (plant-eaters such as cow)

 A consumer that eats another consumer for energy: Is called a secondary or second order consumer May be a carnivore or a herbivore May be a predator May be a scavenger

 A consumer that eats a consumer that already ate a consumer Is called a third order or tertiary consumer May be a carnivore or a herbivore May be a predator May be a scavenger

 Consumers that eat producers & other consumers Are called omnivores, those eat plants and animals. Eg. Human,dogs etc

 Consumers that eat other consumers that have already died are called scavengers Consumers that hunt & kill other consumers are called predators. They animals that are hunted & killed are called prey

 The transfer of energy from sun to producer to primary consumer to secondary consumer to tertiary consumer can be shown in a food chain.

 The greatest amount of energy is found at the base of the pyramid.  The least amount of energy is found at top of the pyramid.

 Are interconnected food chains  They show the feeding relationships in an ecosystem

 Energy is sometimes considered in terms of biomass, the mass of all the organisms and organic material in an area.  There is more biomass at the trophic level of producers and fewer at the trophic level of tertiary consumers. (There are more plants on Earth than there are animals.)  Bio=life Mass=weight  Bio + Mass = Weight of living things within an ecosystem.

 Of all the elements that plants absorbe from the soil, nitrogen is most important for plant growth.theultimate source of nitrogen compounds is the atmosphere,which can not be directly metabolised by plants or animals.  Nitrogen cycle consist following steps : 1) Ammonification.2) Nitrification 3) Nitrogen assimilation 4)Nitrogen fixation 5)Denitrification 6)Sedimentation

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 Nitrogen enters the soil through the decomposition of protein in dead organic matter Amino acids / 2 O 2  CO 2 + H 2 O + NH kJ  This process liberates a lot of energy which can be used by the saprotrophic microbes

 This involves two oxidation processes  The ammonia produced by ammonification is an energy rich substrate for Nitrosomas bacteria They oxidise it to nitrite: NH / 2 O 2  NO H 2 O + 276kJ This in turn provides a substrate for Nitrobacter bacteria oxidise the nitrite to nitrate: NO / 2 O 2  NO kJ  This energy is the only source of energy for these prokaryotes

Root uptake Nitrate NO 3 - Plant protein Soil organic nitrogen Out gass Atmospheric Nitrogen

 Inorganic nitrogen in the form of nitrates,nitrites & ammonia is absorbed by green plants and converted to nitrogenous organic compound.  Nitrates converted to ammonia and form amino acids.  Amino acids are used in the synthesis of proteins.

 Cyanobacteria are nitrogen fixers that also fix carbon (these are photosynthetic)  Rhizobium bacteria are mutualistic with certain plant species e.g. Legumes  They grow in root nodules  Azotobacter are bacteria associated with the rooting zone (the rhizosphere) of plants in grasslands University of Sydney

 Ammonia and nitrates are converted into nitrogen by microbes.  2NO 3 - 2NO 2 - 2NO N 2 Increased nitrite levels NO 3 -  NO 2 -

 Nitrates of the soil are washed away to the sea and locked up in the rocks. This process is called sedimentation.  Nitrogen of rocks is released only when the rocks are exposed.

 The Carbon Cycle is a complex series of processes through which all of the carbon atoms in existence rotate.

 The carbon atoms in our body today have been used in countless other molecules since time began.  The wood burned just a few decades ago could have produced carbon dioxide which through photosynthesis became part of a plant.  When we eat that plant, the same carbon from the wood which was burnt can become part of us. The carbon cycle is the great natural recycler of carbon atoms

 The Oxygen cycle is the biogeochemical cycle that describes the movement of oxygen. The main source of atmospheric oxygen is photosynthesis.biogeochemical cycleoxygen  6CO 2 + 6H 2 O + energy → C 6 H 12 O 6 + 6O 2

 An additional source of atmospheric oxygen comes from photolysis, whereby high energy ultraviolet radiation breaks down atmospheric water and nitrous oxide into component atoms. The free H and N atoms escape into space leaving O 2 in the atmosphere:photolysis ultraviolet  2H 2 O + energy → 4H + O 2 2N 2 O + energy → 4N + O 2

 The water cycle, also known as the hydrologic cycle or H 2 O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Earth  Water can change states among liquid, vapor, and solid at various places in the water cycle. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go, in and out of the atmosphere.liquidvapor solidatmosphere

 The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, runoff, and subsurface flow. In so doing, the water goes through different phases: liquid, solid, and gasocean

 Ecological studies suggest that there exists an ecological balance between biotic and abiotic components in biosphere.Deforestation and human activity disturbs this balance.So we have to control it for the contunity of ecosystem and hence biosphere.