Types of Ecosystems

The presentation is aimed for undergraduate students and covers the details of forest ecosystem, grassland ecosystem, desert ecosystem as well as aquatic ecosystems. It is suitable for compulsory environmental science course at undergraduate level. The content has been simplified for easy understanding of both science as well as humanities students.

2. What is an Ecosystem?
An ecosystem includes all of the living things
(plants, animals and organisms) in a given area,
interacting with each other, and also with their
non-living environments (weather, earth, sun,
soil, climate, atmosphere).
© Dr. Riddhi Datta

3. Types of ecosystems
•Forest ecosystem
•Grassland ecosystem
•Desert ecosystem
•Aquatic ecosystem
© Dr. Riddhi Datta

4. Forest Ecosystem
© Dr. Riddhi Datta

5. Forests
•Forests are formed by a community of plants
which predominantly includes trees, shrubs,
climbers and ground cover.
© Dr. Riddhi Datta

6. Forest ecosystem
•A forest ecosystem is the community formed by plants and
animals of that particular area that interact with the chemical
and physical features of the environment in which they live.
Example: Amazon rain forest ecosystem

•This ecosystem is home to a wide variety of plant and animal
species, which include producers, consumers and
decomposers. These organisms are interdependent on each
other for survival.
© Dr. Riddhi Datta

7. The forest ecosystem has two parts:
•The non-living or abiotic aspects:
Forests on mountains and hills differ from those along river valleys.
Vegetation type depends on:
–Rainfall
–Temperature
–Latitude
–Altitude
–Soil type
•The living or the biotic aspects:
The plants and animals form communities that are specific to each forest type.
–Plants (trees, shrubs, climbers, grasses, and herbs ) including species of angiosperms,
gymnosperms, pteridophytes, bryophytes, fungi and algae.
–Animals including species of mammals, birds, reptiles, amphibians, fish, insects and other
invertebrates .

Forest ecosystem
© Dr. Riddhi Datta

8. Structure of Forest Ecosystems
•Different organisms exist within the forest layers and interact with each other and their
surroundings. Each organism has a role or niche in sustaining the ecosystem.
•Some provide food for other organisms; others provide shelter or control populations through
predation.
Producers
–In a forest ecosystem, plants get their energy from
sunlight.
–They produce their own food through
photosynthesis.
–Plants are called the primary producers, since they
produce the basic foodstuffs for other organisms
within food chains and food webs. © Dr. Riddhi Datta

9. Layers of plants (producers) in forest ecosystem
Emergent Layer: The topmost layer, composed of trees,
woody climbers, and epiphytes spaced far apart. Trees
reach 70 to 80 meters height and is found only in tropical
forests.
Forest Canopy: Trees are closely spaced and are about 10 to
25 meters high but can be as high as 60 meters. They are
always exposed to sunlight and provide fruits, nectar and
seeds to many creatures.
Understory: The forest canopy blocks much of the sunlight
and the understory is dimly-lit. So trees found here young
saplings of the canopy trees. This layer is not as densely
packed as the canopy, and reaches up to 5 to 10 meters.
© Dr. Riddhi Datta

10. Layers of plants (producers) in forest ecosystem
Shrub Layer: There is even less light here than in the
understory. The shrub layer is 1 to 5 meters. Shrubs are rarely
found in tropical forests. Some deciduous temperate forests
have a rich shrub layer.
Non-Woody Herbaceous Ground Cover: There are herbaceous
plants and some grasses. In tropical forests this strata is rarely
more than 10% of the forest area. In contrast, the temperate
forest covers a larger area.
Moss, Cryptogam, and Shallow Soil Layer: This zone includes
fallen logs of trees and decomposing litter of fallen leaves and
twigs. This layer of decomposing organic matter, and cool
temperatures are ideal for cryptogams including ferns, mosses,
lichens, fungi and algae.
© Dr. Riddhi Datta

11. Structure of Forest Ecosystems
Consumers
–Animals cannot produce their own food. All animals, including mammals, insects, birds and
others are called consumers.
–Consumers rely on plants and other animals as a food source.
–Primary consumers only eat plants and are
referred to as herbivores. (Rabbit, Deer)
–Secondary consumers are referred to as carnivores
and feed on herbivores. (Mongoose, Wild cat)
–Tertiary consumers are carnivores that feed on
other carnivores. (Tiger, Lion)
–Omnivores eat both plant and animal matter.
© Dr. Riddhi Datta

12. Forest Ecosystem Animals
•Tropical rain forest provides both shelter and food for huge number of animals which
include:
–birds like cuckoo bird, parrot, swallows, humming bird, eagles
–mammals like orangutans ,monkeys, gibbons, tiger, foxes, hippopotamus, jaguar
–reptiles like crocodiles, alligators, anaconda, flying gecko
•Tropical deciduous forest contains animals like:
–Mammals including deer, elephants, sambars, cheetahs, wild buffaloes, tiger, leopard
– Birds
–Reptiles
–Amphibians
•Coniferous forests consists of rich and varied animal life which includes:
–mammals like mouse deer, musk, rat, porcupine, rabbit, squirrels etc.
–insectivorous birds like grouse, jay cross bill
–reptiles like snakes and lizards

© Dr. Riddhi Datta

13. Decomposers
–Eventually all plants and animals die. These
materials are decomposed by microbes.
–Decomposers break down these complex
organic matters into simpler forms which
can then be used again. Decomposers are
important in that they sustain the nutrient
cycle of ecosystems.
Structure of Forest Ecosystems
© Dr. Riddhi Datta

14. © Dr. Riddhi Datta

15. © Dr. Riddhi Datta

16. © Dr. Riddhi Datta

17. Desert
•A desert is a barren area of landscape where little precipitation occurs and
consequently living conditions are hostile for plant and animal life. About one
third of the land surface of the world is arid or semi-arid.
•The most typical desert landscape in India is seen in the Thar Desert,
Rajasthan.
•There are cold deserts such as in Ladakh, which are located in the high
plateaus of the Himalayas.
•The Great and Little Rann of Kutch are highly specialized arid ecosystems. In
the summers they are similar to a desert landscape. However, as these are
low-lying areas near the sea, they get converted to salt marshes during the
monsoons
•A desert ecosystem is defined by interactions between organism
populations, the climate in which they live, and any other non-living
influences on the habitat.
© Dr. Riddhi Datta

18. Different components of a desert ecosystem
•Abiotic Component:
–The abiotic component includes the nutrients present in the soil and the aerial
environment.
–The characteristic feature of the abiotic component is lack of organic matter
in the soil and scarcity of water.
–Extreme temperatures
© Dr. Riddhi Datta

19. Biotic Component:
Producers
–Mainly shrubs or bushes, some grasses and a rarely trees.
–Most of them are succulents which store water.
–Others have seeds that lay dormant until a rain awakens them.
–These plants are adapted to survive under extreme temperatures and
acute water scarcity (xerophytic adaptation).
–The most famous desert plant is the cactus.
–Xerophytes can hold water inside its soft tissue, has a thick, waxy layer
that minimize transpiration (water loss). Leaves are reduced to spines
and roots are highly developed to search for water. Stems contains
chlorophyll and modified to perform photosynthesis.

Different components of a desert ecosystem
© Dr. Riddhi Datta

20. Biotic Component:
Consumers
These include animals such as insects and reptiles. Besides them, some
rodents, birds and some mammalian vertebrates are also found.
•Desert Insects and Arachnids:
–There are plenty of insects in the desert.
–One of the most common and destructive pests is the locust.
–Not all desert insects are bad, though. The yucca moth is very
important to the yucca plant, and helps in pollination.
–There are also several species of ants in the desert. The
harvester ants gather seeds and store them for use during
the dry season. The honey pot ants eat large amounts of
sugar, so much that their abdomens get too large for them to
move. The rest of the colony feeds off this sugar.
–There are also arachnids in the desert. Spiders are the most
notable arachnids. Some scorpions have poison in their sharp
tails. They sting their predators and their prey with the
piercing tip.

Different components of a desert ecosystem
© Dr. Riddhi Datta

21. Biotic Component:
Consumers
These include animals such as insects and reptiles. Besides them, some
rodents, birds and some mammalian vertebrates are also found.
•Desert Reptiles:
–Reptiles can withstand the extreme temperatures because they
can control their body temperatures very easily. The desert
reptiles belong to two categories: snakes and lizards.
–Snakes: Rattlesnakes, cobra, king snake and the hognose.
–Lizards: They are probably the most bizarre looking animals in the
desert. While some change colors and have sharp scales for
defense, others change their appearance to look threatening.
–Example: Frilled hazard, shingle back, gila monster (poisonous)
Different components of a desert ecosystem
© Dr. Riddhi Datta

22. Different components of a desert ecosystem
Biotic Component:
Consumers
These include animals such as insects and reptiles. Besides them, some
rodents, birds and some mammalian vertebrates are also found.
•Desert Birds:
–Birds come up with interesting ways to survive in the harsh
climate.
–The sand grouse has special feathers that soak up water. It can
then carry the water to its young ones in the nest.
–Gila woodpecker depends on the giant saguaro (cactus) as its
home. The cool, damp inside is safe for the babies.
–Others include roadrunners, ostriches and galahs.
© Dr. Riddhi Datta

23. Different components of a desert ecosystem
Biotic Component:
Consumers
These include animals such as insects and reptiles. Besides them, some rodents,
birds and some mammalian vertebrates are also found.
•Desert Mammals:
–Mammals also have to find ways to stay cool and drink plenty of water.
–Many desert mammals are burrowers. They dig holes in the ground and
stay there during the hot days. They return to the surface at night to feed.
Hamsters, rats and their relatives are all burrowers.
–The kangaroo and spiny anteater both are non-burrowers. Spiny
anteaters are unusual mammals because they lay eggs.
–Others include foxes, jackals and lions. They get their water from the
blood of their prey.
© Dr. Riddhi Datta

24. Different components of a desert ecosystem
Biotic Component:
Consumers
These include animals such as insects and reptiles. Besides them, some
rodents, birds and some mammalian vertebrates are also found.
•Desert Mammals:
–Another interesting mammal found in the deserts is camel.
–There are two types of camels: Bactrian and dromedary.
–Dromedaries have one hump, and Bactrian have two.
–Camels can withstand very high temperatures without
sweating. They also store fat in their humps for food.
–Camels are great for transportation and are used by
humans.
© Dr. Riddhi Datta

25. Different components of a desert ecosystem
Biotic Component:
Decomposers
•Due to poor vegetation the amount of dead organic matter is very less. As a result the
decomposers are very few.
•The common decomposers are some bacteria and fungi, most of which are thermophile.
© Dr. Riddhi Datta

26. © Dr. Riddhi Datta

27. © Dr. Riddhi Datta

28. Grassland
•Grasslands are areas where the vegetation is dominated by grasses and other
herbaceous (non-woody) plants.
•Grasslands occupy about 24% of the earth’s surface.
•They occur in regions too dry for forests and too moist for deserts.
•The annual rainfall ranges between 25-75 cm, usually seasonal.
•The principal grasslands includes:
–Prairies (Canada, USA)
–Pampas (South America)
–Steppes (Europe and Asia)
–Veldts (Africa)
•The highest abundance and greatest diversity of large mammals are found in
these ecosystems.
© Dr. Riddhi Datta

29. Different components of grassland ecosystem
Biotic Components:
•Producer Organisms:
–In grassland, producers are mainly grasses;
though, a few herbs and shrubs also
contribute to primary production of biomass.
–Some of the most common species of
grasses are: Cynodon sp., Desmodium sp.,
Digitaria sp.
© Dr. Riddhi Datta

30. Different components of grassland ecosystem
Biotic Components:
•Consumers:
In grassland, consumers are of three main types:
•Primary Consumers:
–The primary consumers are herbivores feeding directly on grasses.
–These are grazing animals such as Cows, Buffaloes, Sheep, Goats,
Deer, and Rabbits etc.
–Besides them, numerous species of insects, termites, etc. are also
present.
•Secondary Consumers:
–These are carnivores that feed on primary consumers
(Herbivores).
–These include Frogs, Snakes, Lizards, Birds, Foxes, Jackals etc.
•Tertiary Consumers:
–These include hawks etc. which feed on secondary consumers.
© Dr. Riddhi Datta

31. Different components of grassland ecosystem
Biotic Components:
•Decomposers:
–These include wide variety of saprotrophic microorganism like: Bacteria; Fungi;
Actinomycetes.
Abiotic Components:
•These include basic inorganic and organic compounds present in the soil and aerial
environment.
•The essential elements like C, H, N, O, P, S etc. are supplied by water, nitrogen,
nitrates, sulphates, phosphates present in soil and atmosphere.
•The structure of the grassland ecosystem will depend on:
–Temperature
–Altitude
–Rainfall
–Soil chemistry
© Dr. Riddhi Datta

32. Types of grasslands
•Tropical Grasslands
–Tropical grasslands are warm all year round with established rainy and dry
seasons.
–During the rainy season, they receive 50-130 cm of rain.
–Most notable of the tropical grasslands is the African savanna, which is home
to elephants, giraffes, lions and zebras.
–They make excellent grazing area.
•Temperate Grasslands
–Temperate grasslands also have two seasons, growing and dormant.
–During the dormant season, no grass or crops grow because it's too cold.
–These grasslands make for excellent farming because of their deep and
nutrient-rich soils.
–Temperate grasslands receive 25-75 cm of rain a year.
–The most notable temperate grasslands are the North American prairies,
which are home to a wide variety of wildlife, including pronghorn antelope,
mice, jack rabbits, foxes, snakes and coyotes. Grass here can grow quite tall,
reaching up to seven meters in height. Trees are restricted to where there is a
large concentration of water such as a river or lake. © Dr. Riddhi Datta

33. Types of grasslands
•Flood grasslands
– These are flooded seasonally or year round. These grasslands
occur mostly in subtropical and tropical climates.
– The most notable flood grassland is Florida's Everglades.



•Polar or tundra grasslands
– They occur in high to subarctic regions.
– These grasslands consist mainly of shrubs and have a very
short growing season.
© Dr. Riddhi Datta

34. Types of grasslands
•Montane grasslands
– These are high-altitude grasslands located on high mountain
ranges and valleys.
– A notable example of montane grasslands is the paramo of the
Andes.



•Xeric or desert grasslands
–These are very sparse grasslands located in and on the outskirts of
deserts.
–Grass here is highly resistant to disease and drought.
© Dr. Riddhi Datta

35. Grassland ecosystem
food pyramid

36. © Dr. Riddhi Datta

37. Aquatic ecosystem
•Communities of plants and animals living in water are known as aquatic ecosystems.
•They are divided into two main groups:
–Freshwater ecosystems: Found in water containing low concentrations of salts, from
ponds to estuaries.
–Marine ecosystems: Found in the saltwater of seas and oceans.
•The nature of an aquatic ecosystem is controlled by:
–Availability of food
–Dissolved Oxygen
–Temperature
–Salinity
–Sunlight penetration
•Aquatic ecosystems in shallow waters, where there is plenty of sunlight, generally tend to be
the most productive.
© Dr. Riddhi Datta

38. Lake and Pond ecosystem
•A pond ecosystem refers to fresh water ecosystem.
•Usually ponds are shallow water bodies with a depth of 12-15 feet in which the sun rays
can penetrate to the bottom permitting the growth of plants there.
Abiotic components:
–The abiotic substances of Pond ecosystem are formed as a result of the mixture of some
organic and inorganic materials.
–The basic components are
•Water
•Oxygen
•carbon dioxide
•salts of calcium and nitrogen etc.
–Only a small amount of these elements are present in soluble state in pond water, but a large
amount is held in reserve solid form in the bottom sediments as well as within the organisms.
–The rate of release of reserve nutrients ,the solar input and the cycle of temperature, day
length and other climatic conditions regulate the function of the Pond ecosystem.
© Dr. Riddhi Datta

39. Lake and Pond ecosystem
Biotic components:
•Producers:
–The producers are of two types:
•Larger rooted and floating vegetation together
termed macrophytes
•Phytoplanktons which are microscopic floating algae.
–Phytoplanktons are available upto the depth of water where
light penetrates. These are filamentous alga like Oedogonium,
Spirogyra, Oscillatoria and minute floating plants
–The macrophytes include marginal emergent plants like
Typha, submerged plants like Hydrilla, surface floating
plants like Pistia. © Dr. Riddhi Datta

40. Biotic components:
•Consumers:
–Consumers of Pond ecosystem are heterotrophs which depend for their
nutrition on other organisms.
–Zooplanktons form primary consumers include dinoflagellates,
cnidarians, crustaceans, chordates, and molluscs who feed on
phytoplankton.
–Nectic animals like insects, beetles, fishes form secondary consumers as
they feed on zooplanktons.
–Benthic animals like snakes, big fishes live on nectic animals and are
termed tertiary consumers.
Lake and Pond ecosystem
© Dr. Riddhi Datta

41. Biotic components:
•Decomposers:
–Most of the decomposers of Pond ecosystem are saprophytes but some parasites are
also found.
–Bacteria as well as fungi like Saprolegnia are decomposers.
–Generally the decomposers either live in the soil layer beneath water or in the mud.
–They act on dead and decayed organic matter of plants and animals and supply raw
materials to the producers.
Lake and Pond ecosystem
© Dr. Riddhi Datta

42. •Lakes and ponds are also known as lentic
ecosystems and are characterized by a lack of water
movement.
•They are divided into four distinct zones:
–Littoral
–Limnetic
–Profundal
–Benthic.
•Light penetrates the uppermost of these, the
littoral, which contains floating and rooted plants.
•The other zones also each play unique roles in the
ecosystem.
Lake and Pond ecosystem
© Dr. Riddhi Datta

43. River and stream ecosystem
•River and stream ecosystems can be characterized by:
–flowing water that is mostly unidirectional
–a state of continuous physical change
–many different and changing microhabitats
–variability in the flow rates of water
–plants and animals that have adapted to live
within water flow conditions.


•Biotic components are similar to pond ecosystem.
© Dr. Riddhi Datta

44. River and stream ecosystem
Abiotic components:
•Water flow
–Water flow is the main factor that makes river ecology different from other water ecosystems.
–This is known as a lotic (flowing water) system.
–The strength of water flow varies from torrential rapids to slow backwaters.
–The speed of water also varies and is subject to chaotic turbulence.
–Water flow can alter the shape of riverbeds through erosion and sedimentation, creating a variety of changing
habitats.
•Substrate
–The substrate is the surface on which the river organisms live.
–It may be inorganic, consisting of geological material from the catchment area such as boulders, pebbles,
gravel, sand or silt, or it may be organic, including fine particles, decomposed leaves, wood, moss and plants.
–Substrate is generally not permanent and is subject to large changes during flooding events.
•Light
•Temperature
•Water chemistry


© Dr. Riddhi Datta

45. Ocean ecosystem
•The ocean ecosystem is unique among aquatic
ecosystems because of saline water.

•While ocean ecosystems do have much in common with
other aquatic ecosystems, such as freshwater lakes, rivers
or estuaries, they are unique in many ways, especially
because of the high salt water levels.

•The plants, animals and microorganisms are specially
adapted to saline environment.
© Dr. Riddhi Datta

46. Food pyramid
in aquatic
ecosystem
© Dr. Riddhi Datta

47. © Dr. Riddhi Datta