Classification of Ecosystem

Classification of Ecosystem

Intended Learning Outcomes

At the end of this Lecture, students will be able to

• Discuss different types of ecosystems

Content

• Major Ecosystems

• Classification of Ecosystem

Major Ecosystems

• Earth is a vast ecosystem it is however difficult to handle and thus for convenience we generally study it by making artificial subdivisions into units of smaller ecosystem. (eg. Terrestrial ecosystem as, forest ecosystem, desert ecosystem, grassland ecosystem, manmade ecosystem as cropland ecosystem, and aquatic ecosystem as freshwater, marine, etc.)

• An ecosystem thus be separated from each other but it must be remembered that these units of ecosystem are linked with each other forming an integrated system.

Classification of Ecosystem

Different types of ecosystem of biosphere artificially categorized as follows:

• Natural Ecosystems

• Artificial ecosystems

Natural Ecosystems

• These ecosystems operate by themselves under natural conditions without any major interference by man. Based upon the particular kind of habitat, these are further divided as:

• Terrestrial as forest, grassland, desert etc.

• Aquatic which may be further distinguished as

• Fresh water which may be lotic (running water as springs, stream, river) or lentic (standing water as lake, pond, pools, ditch, swamps, etc.)

• Marine Ecosystems: as an ocean or shallow ones like sea or estuary etc.

Artificial Ecosystems

These are maintained by man where, by addition of energy & planned manipulations natural balance is disturbed regularly, for ex, croplands like maize, wheat, rice-fields physico-chemical environment are artificial ecosystems. etc, where man tries to control the biotic community as well as

Marine Ecosystems

• Pond Ecosystem: A Pond as a whole serves a good example of freshwater ecosystem

• Abiotic Components: The chief components are heat, light, pH of water, CO2, oxygen, calcium, nitrogen, phosphates, etc.

• Biotic Components: The various organization that constitute the biotic component are as follows,

• Producers: These are green plants, and some photosynthetic bacteria. The producer fix radiant energy and convert it into organic substances as carbohydrates, protein etc.

Pond Ecosystem

Producers are of following type

• Macrophytes: these are large rooted plants, which include partly or completely submerged hydrophytes, eg Hydrilla, Trapha, Typha.

• Phytoplankton: These are minute floating or submerged lower plants eg algae.

• Consumers: They are heterotrophs which depends for their nutrition on the organic food manufactured by producers.

Primary Consumers:

Benthos: These are animals associated with living plants, detrivores and some other microorganisms

Zooplanktons: These are chiefly rotifers, protozoans, they feed on phytoplankton

• Secondary Consumers: They are the Carnivores which feed on herbivores, these are chiefly insect and fish, most insects & water beetles, they feed on zooplanktons.

• Tertiary Consumers: These are some large fish as game fish, turtles, which feed on small fish and thus become tertiary consumers.

• Decomposers: They are also known as micro-consumers. They decompose dead organic matter of both producers and animal to simple form. Thus they play an important role in the return of minerals again to the pond ecosystem, they are chiefly bacteria, & fungi

Ocean Ecosystem

• Ocean Ecosystem are more stable than pond ecosystem, they occupy 70 % of the earth surface.

• Abiotic Components: Dissolved oxygen, light, temperature, minerals.

Biotic Components:

Producers: These are autotrophs and are also known Primary producers. They are mainly, some microscopic algae (phyto- planlanktons) besides them there are mainly, seaweeds, as brown and red algae also contribute to primary production.

Consumers: They are all heterotrophic macro consumers

Primary Consumer: The herbivores that feed on producers are shrimps, Molluscs, fish, etc.

Secondary Consumers: These are carnivores fish as Herring, Shad, Mackerel, feeding on herbivores.

Tertiary Consumers: These includes, other carnivores fishes like, COD, Halibut, Sea Turtle, Sharks etc.

Decomposers: The microbes active in the decay of dead organic matter of producers, and animals are chiefly, bacteria and some fungi.

Estuarine Ecosystem

• An estuary is a partially enclosed body of water along the coast where fresh water from river and streams meet and mix with salt water from oceans. This Ecosystems are considered as most fertile ecosystem.

• Abiotic Components: Nutrients such as phosphorus and nitrogen, temperature, light, salinity, pH.

• This ecosystem experience wide daily and seasonal fluctuations in temperature and Salinity level because of variation in freshwater in flow.

• Biotic Components:

• Producers: Phyplanktons- these micro-organisms manufacture food by photosynthesis and absorb nutrients such as phosphorous and nitrogen, besides them, mangroves, sea grass, weeds, and salt marshes.

Consumers:

Primary consumers, Zooplanktons that feed on Phytoplankton, besides them some small microorganisms that feed on producers.

Secondary Consumer: Include worms, shellfish, small fish, feeding on Zooplanktons

Tertiary Consumer: Fishes, turtles, crabs, starfishes feeding on secondary consumers.

Decomposers: Fungi & Bacteria are the chief microbes active in decay of dead organic matter.

Riverine Ecosystem

• As Compared with lentic freshwater (Ponds & lakes), lotic waters such as streams, and river have been less studied. However, the various components of an riverine and stream ecosystem can be arranged as follows.

• Producers: The chief producers that remain permanently attached to a firm substrata are green algae as Cladophora, and aquatic mosses.

• Consumers: The consumers show certain features as permanent attachment to firm substrata, presence of hooks & suckers, sticky undersurface, streamline bodies, flattened bodies.. Thus a variety of animal are found, which are fresh spongy and caddis- fly larvae, snails, flat worms etc.

• Decomposers: Various bacteria and fungi like actinomycetes are present which acts as decomposers.

Land Ecosystem

• Grassland Ecosystem: Grassland occupy comparatively fewer area roughly 19 % of the earth’s surface.

• Abiotic Components: These are nutrients present in soil, and aerial environment, thus the elements like, phosphates, sulphates, water, and carbon dioxide, present in soil and in air. Moreover some trace elements are also present.

• Biotic Components:

• Producers: They are mainly grasses a species of Cynadon Desmodium, besides them a few shrubs also contribute some primary production.

Consumers:

Primary Consumers: The herbivores feeding on grasses are grazing animals, as cows, goats, rabbit, etc. besides them there are some insects as termites, millipedes that feed on grasses.

Secondary Consumers: These are carnivores feeding on herbivores these include, animals like, fox, jackals, snakes, frogs, birds.

Tertiary Consumers: Sometimes hawks, vultures, feeding on secondary consumer, thus occupy tertiary consumers.

Decomposers: The microbes active in the decay of dead organic matter of different form are fungi and some bacteria

Grassland Ecosystem

Forest Ecosystem

• Forest Occupy roughly 40 % of the land. The different components of forest ecosystem are as follows:

• Abiotic Components: These are organic & inorganic substances present in the soil and atmosphere. In addition to minerals present in forest we find the dead organic debris, moreover light conditions are different due to complex stratification in the plants.

• Biotic Components:

• Producers: These are mainly trees that show much species and greater degree of stratification. Besides trees there are also present shrubs, and ground vegetation.

• Consumers:

• Primary Consumers: These are herbivores that include animals feeding on tree leaves, ants, beetles, grass hoppers, etc., and large elephants, dears, squirrels, etc.

• Secondary Consumers: These are carnivores, like snakes, birds, lizards, fox, etc. feeding on herbivores.

• Tertiary consumers: These are top carnivores like lion tiger, etc. that eat carnivores of secondary level.

• Decomposers: These are wide variety of microorganisms including, fungi, and bacteria.

Desert Ecosystem

• Desert occupy 17 % of land.

• Abiotic components include, light, temperature, minerals.

• Biotic Components:

• Producers: These are shrubs, especially bushes, some grasses, and few trees. E.g. Cacti, Xerophytes, mosses

• Consumers: The most common animals are reptiles, and insects, there are some rodents, and birds, and above all ship of desert camels, feed on tender plants.