EcosystemsComponents of an Ecosystem

Energy flow in ecosystemEcological Succession

Food Chain, food web and Ecological pyramidsFeatures of Ecosystem

By Vaghela NayanSDJ International College

Meaning of Ecosystems:• The frame or the formation of the living world is called the

Ecosystem.• An ecosystem is a biological environment consisting of all the

living organisms or Biotic component, in a particular area, and the nonliving, or Abiotic component  such as air, soil, water and sunlight with which the organisms interact.• E.g., the air covered environment is suitable for birds.•Water is suitable for fish and aquatic plants.• Vegetation maintain their lives on land or in water.

Classification of Ecosystems:Types of EcosystemNaturalForest

Grassland

Aquatic

Desert

ArtificialTerres-trial

Micro-bial

Aquatic

Natural Ecosystem:• The living species perform their functions as per the natural

situations.• It is further divided into four categories:

1. Desert Ecosystem2. Forest ecosystem3. Grassland Ecosystem4. Aquatic Ecosystem

a) Ecosystem in Streamb) Ecosystem in Pondsc) Ecosystem in Riversd) Ecosystem in Oceane) Ecosystem in Lakes

Artificial Ecosystem:

1. Aquarium Ecosystem2. Agro-farm Ecosystem3. Space Ecosystem

Components or Factors of an Ecosystem:1. Biotic components: These are all the living organisms in the

ecosystem like, plants, animals, bacteria, etcThe biotic components are divided in categories:

A. Producers:• The green plant, which contains chlorophyll makes the use of solar energy

and converts it in to chemical energy of carbohydrates along with the use of H2O and CO2

• This process is called Photosynthesis.• The green plants produce their own food, so they are called producers.

B. Consumers:• The animal species do not possess chlorophyll, and hence they have to

depend on producers for getting food. These animals are called consumers.• They are again subdivided in to five categories.

a) Vegetarian or herbivorous: cow, buffalo, horse, etc.b) Non vegetarian or Carnivorous: lizard, fox, kite, snakec) Herbivorous and Carnivorous both: cat, man, beard) Consumers of carnivorous: wolfe) Omnivorous: lions and tigers.

C. Decomposers:• The bacterial species who are depended on the dead bodies of living

organisms are called decomposers.• They are also known as saprotrophs or rotten feeders.• These living organisms decompose the dead bodies into small particles which

mix in environment as non living substances.

D. Reducers or transformers:• Finally when the bacteria or fungi, uses the micro organic particles of

consumers and producers as their food and releases to the environment simple organic or inorganic substances produced as by-product of their metabolism.• These substances are reused by the producers as minerals which are essential

for the making of food by them.• This is a cyclical exchange of materials between biotic community and abitic

environment of the ecosystem.

2. Abiotic components: the non living organisms that affects the functioning of the Ecosystem are Abiotic components, that are; protein, carbohydrates, DNA, temperature, wind, sunlight, etc.

Energy flow in Ecosystem:

• The proportion of the energy at each stage of the energy flow remains the same• When the energy is transferred from any source, some portion of the

energy is utilized and the other remains inactive.• At every stage of the flow there is increase in the entropy (the

amount of inactive energy)• This entropy exists in the atmosphere.• First law of thermodynamics: “Energy can neither be created or can

not be destroyed but can be converted from one form to the other”• Second law of thermodynamics: “There can be no transformation of

energy unless the energy change is from a concentrated to a dispersed form”

Ecology and Its Succession:

• Meaning of Ecology: “Ecology means the science of residence of the living world.”• “Ecology means the study of mutual relationship of the living

organisms with respect to the environment.” – Edward Arnold• “Ecology means the science of studying the constitution and functions

of the nature.” –Egan Odem

Ecological Succession:• All the living organisms undergo the series of changes in the mental

and physical appearance until that particular biotic community does not attain the compatibility to live and reproduce successfully in the region.• This process of changes is called Ecological Succession.• Characteristics of Ecological Succession:

1. From unstable biotic community to a stable biotic community.2. The stages are regular and directional the an ecologist can predict the

sequences of the future community.3. There is a tendency of increase in diversity and biomass of the community

in the process of succession.4. From simple food chain to complicated food web.5. May be from aquatic to dry and from dry to moderately wet conditions.6. Succession of plants is speedy while it of the animals is slow.

Importance and Types of Ecological Succession• Importance:1. It helps in monitoring the invasion or unequal growth of any animal or botanic

species.2. It helps in reforestation and forest management programmes.• Types:1. Primary succession:

• If development begins in the new area (newly exposed land or rock or lava flow)• Even the succession in the newly formed lake is called primary succession.

2. Secondary Succession:• Development of the community in the area from which it was removed.• It arises where, there is the disturbances created by the humans or animals.• It is usually more rapid as compared to primary succession because of the

richness of the region.

3. Seasonal and Cyclic Succession:• This type of succession arises because of the seasonal changes or because of

the fluctuations in the species interactions or recurring events.• It is natural by means and without the disturbances created by humans or any

other community.

Food chain, Food web and Ecological Pyramids:1. Food Chain:• Flow of energy in an ecosystem is one way process. The sequence of organism through which the energy flows, is known as food chain.

• In a food chain each organism obtains energy from the one at the level below.

• Plants are called producers because they create their own food through photosynthesis

• Animals are consumers because they cannot create their own food, they must eat plants or other animals to get the energy that they need.

2. Food Web:• Food web can be defined as, "a network of food chains which are

interconnected at various tropic levels, so as to form a number of feeding connections amongst different organisms of a biotic community".• It is also known as consumer-resource system.

• A node represents an individual species, or a group of related• species or different stages of a single species.

• A link connects two nodes. Arrows represent links, and• always go from prey to predator.

• The lowest tropic level are called basal species.

• The highest tropic level are called top predators.

• Movement of nutrients is cyclic but of energy is unidirectional and non-cyclic.

Types of Food Chain1. Grazing Food Chain• The consumers utilizing plants as their food , constitute• Grazing food chain. • This food chain begins from green plants and the • Primary consumer is herbivore.• Most of the ecosystem in nature follows this type of food chain.• Ex: grass => grasshopper => birds => falcon2. Parasite Food Chain• Trees Fruit Eating Lice and Bugs Bacteria and fungs

3. Detritus food chain• This type of food chain starts from dead organic matter of• decaying animals and plant bodies to the micro-organisms• and then to detritus feeding organism and to other• predators.• The food chain depends mainly on the influx of organic• matter produced in another system. • The organism of the food chain includes algae, bacteria,• fungi, protozoa, insects, nematodes etc.

• Ecological pyramids are• graphical representations• of the tropic structure• ecosystem.

• Tropic levels are the feeding• positions in a food chain• such as primary producers,• herbivores, primary• carnivore etc.

Ecological Pyramids:

Types of Ecological Pyramid

Three types of ecological pyramids can usually be

distinguished namely:

• Pyramid of numbers

• Pyramid of biomass

• Pyramid of productivity

Pyramid of Numbers• It is the graphic representation of number of• individuals per unit area of various tropic levels.• Large number of producers tend to form the• base.• Lower numbers of top carnivores occupy the tip

Pyramid of biomass• It is the graphical representation of biomass present per unit area at

different tropic levels, with producers at the base and carnivores at the top.

• Biomass is calculated as mass of each individual X no. of individual at tropic levels.

Pyramid of productivity/ Pyramid of Energy• Pyramid of productivity is a graphical representation of the flow of

energy through each tropic level of a food chain over a fixed time period.

• The input of solar energy may be indicated by adding an extra to the base.

Aquatic Ecosystem:

• Abiotic components:• Water• Oxygen• Carbon dioxide

• Biotic Components:• Planktons• See plants• Small fish• Whales

• Source of Energy is Solar energy• Aquatic vegetation produces food with the

help of CO2

• Small insects or worms eats the food produced by producers. They are the first consumers.• Small fishes, frog and big worms are second

consumers.• Big fishes, tortoise and crocodiles are third

consumers.• Fishes are used by men for food.

Forest Ecosystem:• Abiotic components:• Water• Salt• Oxygen• Carbon dioxide

• Biotic Components:• Deers• Stag• Elephants• Tigers• Lions

• With the help of solar energy, trees produces the food, ad they are the producers in forest ecosystem.• Deers, stags, elephants and birds will be

depending on trees and they will be the first consumers.• Tigers lions kites and snakes will be eating

the first consumers and will be treated as second consumers in the forest ecosystem.

Desert-vegetation Ecosystem:• Abiotic components:• Land• Oxygen• Carbon dioxide• Solar energy

• Biotic components:• Thorny trees and grass fodders• Goat, sheep and other birds• Panther, dogs• Shepherds• Tamed animals