Ecosystems

What is Ecology?Ecology is the study of relationships between living things and their environment.

What is an ecosystem?An ecosystem is a natural unit consisting of all plants, animals and micro-organisms (biotic factors) in an area functioning together with all of the non-living physical (abiotic) factors of the environment.

An ecosystem can be as large as the Sahara Desert, or as small as a puddle!!!Ecosystems are more than just the organisms they contain. Geography, weather, climate and geologic factors also influence the interactions within an ecosystem.

Components of an Ecosystem

BIOTIC COMPONENTS

Primary producersHerbivoresCarnivoresOmnivores Detritivores

All of these vary over space/time

ContABIOTIC COMPONENTSSunlightTemperaturePrecipitationWater or moistureSoil or water chemistry (e.g., P, NH4+)

Producers, Consumers, DecomposersProducers = plants etc. that capture energy from the sunHerbivores = plant-eatersCarnivores = animal-eaters

CarnivoreHerbivoreProducer

Cont..Producers (Plants, algae)--capture energy, produce complex organic compoundsPrimary consumers--feed on producersSecondary consumers--feed on primary consumersTertiary consumers--feed on secondary consumers

ContDetritivores--invertebrates that feed on organic wastes and dead organisms (detritus) from all trophic levels

Decomposers--bacteria and fungi that break down dead material into inorganic materials

Cont..photoautotrophsimpleinorganiccompoundscomplexorganic compoundslightheterotrophssimpleinorganiccompoundscomplexorganic compoundsheat

Energy Flow in the EcosystemThe flow of energy in an ecosystem begin first with the input of energy from the sun. Energy from the sun is captured by green plants. with the help of this energy they absorb the nutrients from the soil and air, and produces the FOOD (photosynthesis). It is consumed by the higher levels and finally reaches in soil.Thus everything is cycling.

THE WATER CYCLE

THE CARBON CYCLE

THE NITROGEN CYCLE

Food Chaingrassgrasshoppermousesnake hawk

Food Web

Ecological PyramidsThe standing crop, productivity, number of organisms, etc. of an ecosystem can be conveniently depicted using pyramids, where the size of each compartment represents the amount of the item in each trophic level of a food chain.

Energy PyramidA pyramid of energy depicts the energy flow, or productivity, of each trophic level. Due to the Laws of Thermodynamics, each higher level must be smaller than lower levels, due to loss of some energy as heat (via respiration) within each level. An energy pyramids shape shows how the amount of useful energy that enters each level chemical energy in the form of food decreases as it is used by the organisms in that level.

Cont..

Cont

Ecological SuccessionIt is a process through which ecosystems tend to change over timeExample: if a forest is cleared;Colonies of small plants and animalsGrasslandShrub landWoodlandForest

Forest Ecosystem

Cont a forest is the community of plants and the animals in its very undisturbed state.A forest ecosystem hasThe abiotic aspects; type of forest depends on aboitic conditions such as topography, temperature, rainfall ..Biotic aspects; plants and animals

Types of forestsTropical rainforests hot & humid regionAnnual rainfall- 2000 to 4500 mm. Found in south and central America, Western & Central Africa, South East Asia, and some islands of Indian & Pacific Oceans.Tropical forests are considered important because it helps in recycling water.Amazone rain forestWestern ghats

Tropical rain forest

Cont..Temperate forestsCold in winter and warm & humid in summer.In moderate conditionAnnual rainfall is 750-2000 mmSoil is richFound in western and Central Europe, eastern Asia and eastern North America.

Temperate forests

Cont..Coniferous forestsMany coniferous trees are found in this region like spruce, fir, pine etc.

Found in northern parts of Northern America, Europe and Asia.

The soil in these forests is acidic and humus-rich.

Cont..

GrasslandA wide range of landscape in which vegetation is grass and small plantsThe rain is low to grow large treesSoil quality is poor and low depth

Types OF GrasslandsThe Himalayan pastures : situated in himalayaIt helps in the migration of animals during winter and summerColourfull flowering plants

Cont..Terai grassland :South of the himalayan foothillsPatches of tall elephant grass (5m height)Also includes marshes

Cont..Shola grasslandIn western ghats, nilgiri and anamalaiOn the slopes and forest habitats

Desert ecosystem

Cont..Extremely specialised and sensitive ecosystemsWestern India, Deccan plateauExtremely dry climateCold desert are there like LadakhThar desert; largest in IndiaCertain shrubs are growing during rainfall, and they are capable to survive without additional water

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