ECOSYSTEM

The study of ecosystem is called Ecology

1] Biotic (living)

  

   i.producers or autotrophs, 

   ii.consumers or heterotrophs, and 

         -Herbivorus

         -Carnivorus

         -Omnivorous

   iii.decomposers or detritivores.

2]Abiotic (Non-living)

    i.Physical factors

    -sun 

    -wind 

    -soil 

    -water

    ii.Chemical factors

     -Minerals(P, Si)    

FOOD CHAIN

The sequence of eating and being eaten in an ecosystem is known as food chain.

Example:

   1.Grass-Grass Hopper-Frog-Snake -Hawk  <Grassland ecosystem>

   2.phytoplankton-Water Fleas-Small Fish-Big fish <Pond ecosystem>

   3.Lichen - Reindeer - Man <Arctic Tundra Ecosystem>

THINGS TO REMEMBER:

* September 16 to 23 - Ozone Week

*ISO no. for environmental friendly product are given 14000 Certification

*Intergovernmental Panel on Climate Change (IPCC) head of it was Dr. R.K Pachauri won 2007 Nobel Peace Prize

* World Environment Day - 5th June

* World Population Day - 11th July

*Tropical Rain Forest contains Refflesia(a 7kg flower!).

Trophic Level

Producer and user are organized in a definite way in an ecosystem and their relationship with the population size is expressed as Trophic structure together. Every amount of food is known as trophy amount. 

Major functional Attribute of an ecosystem are as follows:

1. Food Chain, Food web and trophic structure

2. Energy Flow 

3. Cycling of nutrients

4. Primary and 2ndry production

5. Ecosystem development and regulation

Food Web

It is a network of food chain where different types of organisms are connected at different trophic level. So, that there are number of option of eating or being eaten at each trophic level.



Types :

1)Detritus Food Chain - It start with dead organic matters which the detritivores and decomposes consume

DEAD ORGANIC MATTER -> FUNGI -> BACTERIA

2)Grazing Food Chain - It start with green plants

Phytoplankton  -> zooplankton -> SMALL FISH -> BIG FISH

Ecological pyramid

An ecological pyramid (also a trophic pyramid, an Eltonian pyramid, an energy pyramid, or sometimes a food pyramid) is a graphical representation designed to display the biomass or bioproductivity of a given ecosystem at each trophic level. 


An energy pyramid shows how much energy is retained at each trophical stage in the form of new biomass, while a biomass pyramid shows how much biomass (the sum of l) is retained.

A pyramid of energy shows how much energy is retained in the form of new biomass at each trophic level, while a pyramid of biomass shows how much biomass (the amount of living or organic matter present in an organism) is present in the organisms.

There is also a pyramid of numbers representing the number of individual organisms at each trophic level. 

Pyramids of energy are normally upright, but other pyramids can be inverted or take other shapes.

TYPES OF ECOLOGICAL PYRAMID

1] Pyramid of energy : 

*The output or turnover (the rate at which energy or mass is transferred from one trophic level to the next) of biomass at each trophic level is shown by an energy pyramid or productivity pyramid

*Instead of showing a single snapshot in time, productivity pyramids show the flow of energy through the food chain. 

*Typical units are grams per square meter per year or calories per square meter per year. 

*As with the others, this graph shows producers at the bottom and higher trophic levels on top.

*For example, grass gives energy to a grasshopper, which gives energy to frogs (or whatever eats it), which gives energy to the snakes (or whatever eats it), and so on. The higher on the pyramid, the more energy it gets

2]Pyramid of biomass :

*A pyramid of biomass shows the total biomass of the organisms involved at each trophic level of an ecosystem. These pyramids are not necessarily upright.

*There can be lower amounts of biomass at the bottom of the pyramid if the rate of primary production per unit biomass is high.


A pyramid of biomass shows the relationship between biomass and trophic level by quantifying the biomass present at each trophic level of an ecological community at a particular time.

*It is a graphical representation of biomass (total amount of living or organic matter in an ecosystem) present in unit area in different trophic levels. 

*Typical units are grams per square meter, or calories per square meter. The pyramid of biomass may be "inverted".

*For example, at any given point in a pond environment, the standing phytoplankton crop, the main producers, will be lower than the mass of the heterotrophs, including fish and insects. This is explained by the fact that the phytoplankton reproduces very fast, but has much shorter individual lives.

3]Pyramid of numbers :

*A pyramid of numbers shows graphically the population, or abundance, in terms of the number of individual organisms involved at each level in a food chain. 

*This shows the number of organisms in each trophic level without any consideration for their individual sizes or biomass. The pyramid is not necessarily upright.


*For example, it will be inverted if beetles are feeding from the output of forest trees, or parasites are feeding on large host animals.

PRIMARY AND SECONDARY PRODUCTION

Let, Primary Productivity  = PP  Then,

GPP = NPP + R ( Respiration Rate)

PRIMARY PRODUCTION

*In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide.

*It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through chemosynthesis, which uses the oxidation or reduction of inorganic chemical compounds as its source of energy.

* Almost all life on Earth relies directly or indirectly on primary production. The organisms responsible for primary production are known as primary producers or autotrophs, and form the base of the food chain.

*Annual Average of GPP of some Measure Ecosystem

1. DESERT & TUNDRA - 200 Kcal/m2/yr

2. OCEANS - 1,000 Kcal/m2/yr

3. GRASSLAND - 2,500 Kcal/m2/yr

SECONDARY PRODUCTION

The Energy Stored at a consumer level use by the next Trophic Level is known as Secondary Production.

ECOLOGICAL SUCCESSION

Ecological Succession is defined as an orderly process of chains in the structure and function of the community with time, mediated by modification in the physical environment ultimately culminating in a stable ecosystem known as Climax. 


The whole sequence of transitory communities is known as SEREL STAGES or SERIS, where the community which is first and foremost established in the area is called Pioneer Community.

Eological Succession starting on different type of area are named differently are as follows:

1.Hydrarch Succession

Hydrarch: Plant succession starting on relatively shallow water, such as ponds and lakes, and culminating in a mature forest

2.Mesarch Succession:

The succession starting from a habitat where adequate moisture condition are present. 

3. Xerarch Succession:

Plant succession, beginning on bare ground or rock and culminating in a mature forest climax. The pioneer species, such as lichens and mosses, lead to gradual soil accumulation.

They can be of three Types :

(i) Psammosere:
     Where the succession starts on   
     sandy habitat.

(ii) Lithosere:
     Where the succession starts on the surface of rocks.

(iii) Halosere: 

      The succession occurring at saline water or soil is known as holosere.

Process of succession:

The entire process of primary autotrophic succession is completed through a series of sequential steps followed by one after another.
The different sequential steps may be outlined as below:

(1) Nudation  :  It is a process of developing a bare area without any form of life for the arrival of new species.

(2) Invasion  :  The successful establishment of a species in a bare area is called as invasion.

(3) Competition and Co-action  :  

*As the species aggregate at a limited space, there happens competition (inter as well as intra specific) mainly for space and nutrition. 

*Secondly the life process of one individual is affected by the surrounding species in various ways which is known as coaction. 

*The species which are found unable to compete with others in the existing environment get discarded.

(4) Reaction :  

*The species present in an environment constantly interact with it there by causing its modification. 

*The mechanism of the modification of the environment through the influence of living organisms on it, is known as reaction.

(5) Stablisation(Climax) : 

*At last a final or terminal community is established. Which is stabilized for a longer period of time and which can maintain an equilibrium with the environment of that area. 

*This community is known as climax community and the stage is as climax stage.

HYDROSERE 

The succession starting from aquatic habitat is known as “Hydrach” and the series of changes occurring in the vegetation of hydrarch are called ‘Hydrosere’.

XEROSERE

Succession taking place in xeric havitat like sand or rocks where moisute is present at minimal amount is known as xerosere.

Xeroseres can further be subdivided into:

(i) Psammosere : Where the succession starts on sandy habitat.


(ii) Lithosere : Where the succession starts on the surface of rocks.