1. Components of an Ecosystem
(Organisation or Structural aspect of an ecosystem)
An ecosystem comprises of two basic components
i) Abiotic components and
ii) Biotic components
The relationship between the biotic components and abiotic components of an ecosystem is called 'holocoenosis'.
Sub Topics
1. Abiotic Components
2. Biotic Components
Abiotic Components
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These include the non-living, physico - chemical factors such as air, water, soil and the basic elements and compounds of the environment.
Abiotic factors are broadly classified under three categories.
Climatic factors which include the climatic regime and physical factors of the environment like light, humidity, atmospheric temperature, wind, etc.
Edaphic factors which are related to the structure and composition of soil including its physical and chemical properties, like soil and its types, soil profile, minerals, organic matter, soil
water, soil organisms.
Inorganic substances like water, carbon, sulphur, nitrogen, phosphorus and so on. Organic substances like proteins, lipids, carbohydrates, humic substances etc.
Biotic Components
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It comprises the living part of the environment, which includes the association of a number of interrelated populations belonging to different species in a common environment.
The populations are that of animal community, plant community and microbial community.
Biotic community is distinguished into autotrophs, heterotrophs and saprotrophs.

2. Autotrophs (Gr: auto - self, trophos - feeder) are also called producers, convertors or transducers.
These are photosynthetic plants, generally chlorophyll bearing, which synthesize high-energy complex organic compounds (food) from inorganic raw materials with the help of sunlight,
and the process is referred as photosynthesis.
Autortophs form the basis of any biotic system.
In terrestrial ecosystems, the autotrophs are mainly the rooted plants.
In aquatic ecosystems, floating plants called phytoplankton and shallow water rooted plants called macrophytes are the dominant producers.
Heterotrophs (Gr: heteros - other; trophs - feeder) are called consumers, which are generally animals feeding on other organisms.
Consumer's also referred as phagotrophs (phago - to ingest or swallow) or macroconsumers are mainly herbivores and carnivores.
Herbivores are referred as First order consumers or primary consumers, as they feed directly on plants.
For e.g., Terrestrial ecosystem consumers like cattle, deer, rabbit, grass hopper, etc.
Aquatic ecosystem consumers like protozoans, crustaceans, etc.
Carnivores are animals, which feed or prey upon other animals.
Primary carnivores or Second order consumers include the animals which feed on the herbivorous animals.
For e.g., fox, frog, predatory birds, smaller fishes, snakes, etc.
Secondary carnivores or Third order consumers include the animals, which feed on the primary carnivores.
For e.g., wolf, peacock, owl, etc.
Secondary carnivores are preyed upon by some larger carnivores.
Tertiary carnivores or Quaternary consumers include the animals, which feed on the secondary carnivores.
For e.g., lion, tiger, etc.
These are not eaten by any other animals.
The larger carnivores, which cannot be preyed upon further are called top carnivores.

3. Saprotrophs (Gr: sapros - rotten; trophos - feeder) are also called decomposers or reducers. They break down the complex organic compounds of dead matter (of plants and animals).
Decomposers do not ingest their food. Instead they secrete digestive enzymes into the dead and decaying plant and animal remains to digest the organic material. Enzymes act upon the
complex organic compounds of the dead matter.
Decomposers absorb a part of the decomposition products for their own nourishment. The remaining substances are added as minerals to the substratum (mineralisation).
Released minerals are reused (utilised) as nutrients by the plants (producers).
Two Major Components Of EcosystemDocument Transcript
1. Two Major Components of Ecosystem 1. Abiotic • Consists of nonliving chemical and physical components such as water, air, nutrients in the soil or
water and solar energy. • Physical and chemical factors that influence living organisms in land (terrestrial) ecosystems and aquatic life zones Terrestrial
Ecosystem Aquatic Life Zone 1. Sunlight 1. Light penetration 2. Temperature 2. Water current 3. Precipitation 3. Dissolved nutrient concentrations4. 4.
Wind (especially N and P) 5. Latitude 4. Suspended solids (distance from equator) 5. Salinity(the amounts of various 6. Altitude inorganic minerals or salts
dissolved (distance above sea level) in a given volume of water) 7. Fire frequency 8. Soil 2. Biotic • Made up of biological components consisting of living
and dead plants, animals and microorganisms • The Major Biological Components of Ecosystem a. Producers (Autotrophs)(self-feeders) o Make their own
food from compounds that are obtained from their environment. o Are the source of all food in an ecosystem o On land most producers are green plants. o
In freshwater and marine ecosystems, algae and plants are the major producers near shorelines o In open water, the dominant producers are
phytoplankton (most of them microscopic) that float or drift in the water. o Most producers capture sunlight to make carbohydrates (such as glucose) by
photosynthesis o A few producers, mostly specialized bacteria, can convert simple compounds from their environment into
2. more complex nutrient compounds without sunlight a process called chemosynthesis b. Consumers (Heterotrophs) (“other feeders”) o Get their energy
and nutrients by feeding on other organisms or their remains. a. Primary consumers = are those that eat producers (plants) as a source of food also known
as herbivores. b. Secondary consumers or carnivores = eat other animals c. Omnivores = have mixed diet that include both plants and animals d.
Decomposer = Mostly certain types of bacteria and fungi are specialized consumers that recycle organic matter in ecosystems =They do this by breaking
down (biodegrading) dead organic material to get nutrients and releasing the resulting simpler inorganic compounds into the soil and water, where they
can be taken up as nutrients by producers Detritus • Consisting of parts of dead organisms and cast-off fragments and wastes of living organisms. KINDS
OF ORGANISM INTERACTIONS 1. Predation = situation in w/c an organism of one species (the predator) captures and feeds on parts or all of an
organism of another species (the prey) 2. Competition = a kind of interaction in w/c two organisms strive to obtain the same limited resource and in the
process both organisms are harmed to some extent. a. Intraspecific competition – competition w/c is between members of the same species b.
Interspecific competition – competition among organisms of different species 3. Symbiotic relationships a. Symbiosis – is a close, long lasting, physical
relationship between two different species of organisms.
The physical 3. – the two organisms are usually in physical contact and at least one of the organisms derives some sort of benefit from this contact b.
Parasitism – is a relationship in w/c one organism, known as the parasite, lives in or on another organism, known as the host, from w/c it derives

4. nourishment. 1), Ectoparasite – those that live on the surface of their host 2). Endoparasite – those that live inside the bodies of their hosts c.
Commensalism – relationship in w/c one organism benefits while the other is not affected. Ex Remora fish attached to shark d. Mutualism – symbiotic
relationships that are actually beneficial to both species of organisms involved Module 2 ABIOTIC COMPONENTS OF THE ENVIRONMENT Abiotic
components & chemical factors that influence the various metabolic & The major abiotic factors are climatic, edaphic physiological processes of the
organisms as well as regulate their functions & These factors are classified as resources and conditions A. Resources – are those factors that can be
consumed or directly utilized by organisms like nitrogen, phosphorus and potassium . B. Environmental conditions – Are factors that are not directly utilized
by the organisms but affect the growth and survival of the organisms. – However, these factors can also be changed or affected by the organisms such as
temperature or salinity 1. Climatic Factors topographic factors
The higher the latitude the lesser solar radiation is intercepted because the radiations are spread over larger The amount of solar radiation varies over
the earth surface depending on the latitude and altitude The solar radiation travels through the space as waves describe as wavelength, Energy that
travels through space in the form of waves of particles. Is the amount of light intercepted by the earth that causes thermal patterns. 4. Climate – is the
result of interplay of the seasonal factors like temperature, humidity, precipitation and light conditions in a particular area – it places the greatest constraint
on the organisms and it influences the weather condition in a local area. – a region’s general pattern of atmospheric or weather conditions over a long
period – is the long term average pattern of weather – it determines the availability of heat and water, influences the amount of solar radiation that can be
captured by the plants Weather – is a temporary condition of the atmospheres, a combination of temperature, pressure, humidity, precipitation, sunshine
wind direction and speed, cloudiness and other atmospheric conditions at specific time and place Climate and weather are directly affected by energy and
physical process in the environment is also influenced by the activities of living organisms. a. Solar radiations
The rotation of the earth and its movements around the sun gen The pattern controls the mean annual temperature around the globe The equatorial
region receives the most radiation and equal occurrence of day and night. The Artic and Antartic region have varied daylengths from continuous daytime
during summer solstice. The seasonality of solar radiation, temperature and day length also increases with latitude. 5. area. This explains why
temperature is higher in tropic than at the poles. Plants can tolerate extreme cold by frost hardening its body part but the response is for short period
only. Temperature also affects the function of plants and cold- blooded animals by controlling the rate of their metabolism. It then influences the growth
of plants; the higher the altitude the greater is the pressure thus plants become stunted. Air temperature decreases with altitude, the higher the altitude
the lower the temperature, decreasing by 0.6°C every 100 meters. Temperature varies depending on the latitude, altitude, season, and continents,
microclimatic variation and depth variation. Variation in the environmental temperature affects the distribution and abundance of organisms. It also
influences the amount of moisture and the need for it by the organisms because it takes part in the chemical reactions in all living organisms. It has
pervasive influence on life on earth by affecting the rates of photosynthesis and stored energy in plants Is the degree of heat that is natural to the body
of living things. erates the wind and ocean currents. These movements influence the distribution of rainfall. b. Temperature
The amount of water vapor in the air Animals on the other hand can maintain a fairly constant internal body temperature by using their behavioral and
physiological means but they are still categorized into three major groups; a. Poikilothermic (variable body temperature)– have variable body temperature
influenced mainly by the existing temperature. Ex Sea lamprey b. Homeothermic (constant body temperature) – are organisms that have body temperature
that are independent of the environment Ex birds, mammals c. Heterotherms – organisms that can switch to endotherms (source of their body heat is
internal) and homoethermic. During environmental extremes, some animals may enter a state of torpor (state of mental and motor inactivity with partial or
total insensibility) by reducing their metabolism, heartbeat and respiration to reduce their energy cost and stay warm or cool. Hibernation – seasonal torpor
over winter. Condition especially mammals, of passing the winter in a torpid state in w/c the body temperature drops nearly to freezing and the metabolism
drops close to zero. - Amphibians move in and out the water while desert animals burrow their bodies to the ground to seek shade. - Some desert animals
also use hyperthermia to reduce the difference between body and environmental temperaturewhile others employ countercurrent circulation in the blood to
reduce heat loss. c. Humidity Some plants were able to survive in very low temperature by their creeping habits to avoid too much exposure to extreme
low temperature. Plants living in desert have thick barks and small leaves to reduce the loss of water. Prolonged exposure to extreme conditions like
heat and cold could affect their physiological processes and may cause death. 6.
The movement of air and water significantly influence the ventilation of an organism thus it affects the distribution and survival of organisms As the earth
spin on its axis, it deflects the air and water to the right of Northern hemisphere and left of the Southern hemisphere called as Coriolis effect. = the effect
produces the three types of global wind pattern a. the westerlies b. the northeast trade winds c. the easterlies The global pattern of circulation is the
vertical movements of the air masses and this is due to the heating and cooling air mass that rise and sink. Organisms that have poor water control lives
in damp habitat while organism that have the ability to regulate their water intake survive in desert environment. d. Movement of air and water The
capability of the organisms to adapt to these variable moisture condition influences their distribution in a habitat. Other factors such as temperature and
wind significantly affect the rate of evaporation that affect the humidity. Humidity and shortage of available water are very much linked. Areas with low
water such as desert have also low humidity. The relative humidity of the atmosphere greatly influenced the land organisms The greater the humidity the
lesser is the risk of dehydration in the organisms When the particles of water or ice become too heavy in the air, it will fall as rain or snow. Warm air
can hold more water than cold air. If the cool air have constant amount of moisture, the relative humidity increases and if it reaches the saturation vapor
pressure it will condense and becomes cloud. Temperature plays a role in climate and to the amount of water it can hold The amount of water in the
air expressed as the percentage of saturation vapor pressure is relative humidity 7.
Soil served as the habitat of animals and the anchoring medium of plants and source of their nutrients and water a. Soil Characteristics o Soil is a complex
mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and billions of living organisms, most of them microscopic decomposers. o
Soil is a renewable resource o Soil was formed from the weathering of rocks and minerals through mechanical or physical weathering for a very long time.
o Plants and animals have pronounced influence on soil development when they colonize the weathered rocks o The roots of the plants penetrate the soil
and pump up the nutrients converting this to organic form through photosynthesis o When plants die, the bacteria will decompose the debris into inorganic
nutrients. Soil is a natural product of unconsolidated mineral and organic matter on Earth’s surface. It is the medium in w/c plant grows and the site of the
decomposition of organic matter. Are the physico-chemical properties of soil that limit the abundance and distribution of living organisms Heavy water
with high breaking action is damaging to the organisms in the areas. 2. Edaphic Factors The wave action in shore also affects the distribution of the

5. different species. The greater is the density and viscosity of the water the slower the movement and so its dessicating effect. It can serve as
dessicating medium especially in windy areas of mountains. 8.
Contain most of a soil’s inorganic matter, mostly broken-down rock consisting of varying mixtures of sand, silt, clay,and gravel The color of its topsoil
tells us a lot about how useful a soil is for growing crops. For example darkbrown or black topsoil is nitrogen-rich and high in organic matter. Gray, bright
yellow, or red topsoils are low in organic matter and need nitrogen enrichment to support most crops. 3. The B Horizon (subsoil) and the C Horizon (parent
material) A fertile soil that produces high crop yields has a thick topsoil layer with lots of humus. This helps topsoil hold water and nutrients taken up by
plant roots It is usually darker and looser than deeper layers. A porous mixture of partially decomposed organic matter called humus(this material
helps retain water and water-soluble nutrients, w/c can be taken up by plant roots) and some inorganic mineral particles. Normally it is brown or black. 2.
The Topsoil Layer or A Horizon Consists mostly of freshly fallen and partially decomposed leaves, twigs, animal waste, fungi, and other organic
materials 9. o Some invertebrates like millipedes, earthworms and mites consume the fresh materials in the soil and leave the partially decomposed in
the soil through their excreta thereby increasing the amount of inorganic materials in the soil. o Mature soils area ranged is a series of zones called soil
horizon, each with distinct texture and composition that varies with different types of soils o A cross-sectional view of the horizons in a soil is called a soil
profile o Most mature soils have at least three of the possible horizons 1. The Surface Litter Layer, or O Horizon (Top Layer)
As the water seeps down, it dissolves various soil components in upper layers and carries them to lower layers in a process called leaching (process in
which various chemicals in upper layers of soil are dissolved and carried to lower layers and, in some cases, to the groundwater) b. Substrate texture and
structure o Texture is determined by the proportions of the soil particles of different sizes; the sand (medium-size particles) silt (fine particles), gravel
(coarse to very coarse particles) and clay (very fine particles). Soils with roughly equal mixtures of clay, sand, silt, and humus are called loams o Loams
are the best soils for growing most crops because they hold lots of water but not too tightly for plant roots to absorb o It is important in the movement and
retention of water in the soil. o Soil particles, particularly clay-humus complex are important to nutrient availability and to the carbon exchange of the soil o
Color is also another identification of soil, pale brown to reddish and yellowish color indicates good drainage of water while dark brown and blackish color
indicates poor drainage. o Though the dark colors may indicate the presence of organic matter it does not always indicate its richness in organic matter
because some rocks that are volcanic in origin have dark color as well. c. Ph o The acidity or alkalinity of a soil, as measured by its pH influences the
uptake of soil nutrients by plants o The ph of the soil or water influences the distribution and abundance of organisms o A ph that is either too low or too
high is damaging to the organisms. The C Horizon lies on a base of unweathered parent rock called bedrock 10.
Essential resources are not replaceable by an alternatives such as nutrients while substitutable are resources that can be partly or wholly replaced when
the consumption of the resources has exceeded its maximum ability to support. 1. Light Resources may be categorized as essential or substitutable.
The resources are the materials that are utilized by the organism for the maintenance of their bodies such as solar radiation, nutrients, food and space
11. o It may also indirectly affect the organism by affecting the nutrient and concentrate the toxin in the soil. o Acidic soil may build up toxic ions while
alkaline conditions may trap the nutrients in the soil 3. Salinity • Salinity is the measure of salt in the water • It can exert very significant effects on the
abundance and distribution of species because of difference in water and ionic control abilities of organism • Hypotonic organisms such as bony fish find it
very hard to live in normal seawater because they have high risk of water loss. • Salt tolerant plants (halophytes) tolerate high salinity by concentrating
electrolytes in the cell vacuoles while the cytoplasm are left normal. 4. Contaminants and pollutants • Contaminants and pollutants are materials that
maybe present in the environment that may or may not cause negative biological effects to the organisms • Such materials may be derived from natural
and or anthropogenic sources to w/c the organisms may respond differently. • Some species may develop tolerance and protection from the polluting
substances such as that of the tolerance of bacteria against antibiotics and that of the insects with the pesticides. B. LIMITING RESOURCES
Random variations due to cloud cover, shading and reflections of waves affect the plants species by limiting the potential for optimal utilization of light. 2.
Inorganic materials Three inorganic materials are considered vital for the living organisms in the environment. a) Water molecules o Needed by all
organisms to survive thus influence their distribution and abundance. o It is needed by plant for transpiration (loss of water vapor at the aerial portion of the
plant like leaves) and photosynthesis (process where in plants convert radiant energy to chemical energy) while animals used water as a medium for many
metabolic activities in their body. o Animals usually drink water or obtain it from food it takes while plants usually obtain water from the soil using their
elaborate root system. b) Carbon dioxide o Is fixed by plants into living materials through photosynthesis c) Oxygen o Becomes a limiting factor in aquatic
or water logged sediments because of its role in aerobic respiration of animals Systematic variation may influence the control processes of the organism
to develop diurnal and seasonal rhythms. Radiation is greatest at low latitudes while seasonal variation is greatest at high latitudes. Variation in the
amount of solar radiation however, varies depending upon the latitude. Solar radiation differs from other resources because it passes through the
system only once and if it is not captured and used immediately, it is lost. Plant utilizes only the wavelength between 400-700 nm and this band is called
photosynthetically active radiation (PAR) and falls within visible spectrum. Light is a resource continuum that is comprised of spectrum of different
wavelengths that are usable for photosynthesis. 12.
13. 1. Nutrients • Macro and micronutrients are required by organisms to function properly & they obtain these from the food, soil or surrounding water. •
Macronutrients include nitrogen, phosphorus, sulfur, potassium, calcium, magnesium and iron • It is required by all organism in large quantities that it
become a limiting factor to some organism when it is limited in the environment • The extraction by plants of nutrients from the soil is done through the root
system • These are close relationship between water and minerals, so lack of water can make the mineral unavailable 2. Food • The heterotrophic
organisms require foods and each organisms is alternately a consumer or a prey within the food chain (series of organisms in w/c each eats or
decomposes the preceding one)or food web(complex network of many interconnected food chains and feeding relationships). • Some organisms are
specialist, feeding upon a single species only thus these are restricted closely to source of prey and force to live in patches • Moreover, many food sources
are seasonal and the nutritional value may vary with season. • Carnivores have difficulties finding, capturing and handling prey items and most of times,
their prey have developed physical or behavioral defenses against their consumers. This process is called coevolution 3. Space • All organisms require
space within w/c they can live • Plants may require only small space but the top carnivores require bigger space.
14. • Space becomes an important resource because it contains other resource such as food. • However, space is also required by other organisms for
their growth, breeding, hibernation and for nesting.

6. 1. Abiotic Components
Abiotic components are such physical and chemical factors of an ecosystem as light, temperature, atmosphere gases(nitrogen, oxygen, carbon dioxide are the most important), water, wind,
soil. These specific abiotic factors represent the geological, geographical, hydrological and climatological features of a particular ecosystem. Separately:
Water, which is at the same time an essential element to life and a milieu
Air, which provides oxygen, nitrogen, and carbon dioxide to living species and allows the dissemination of pollen and spores
Soil, at the same time source of nutriment and physical support. The salinity, nitrogen and phosphorus content, ability to retain water, and density are all influential.
Temperature, which should not exceed certain extremes, even if tolerance to heat is significant for some species
Light, which provides energy to the ecosystem through photosynthesis
Natural disasters can also be considered abiotic. According to the intermediate disturbance hypothesis, a moderate amount of disturbance does good to increase the biodiversity.
2. Biotic Components
The living organisms are the biotic components of an ecosystem. In ecosystems, living things are classified after the way they get their food.
Biotic Components include the following --
Autotrophs produce their own organic nutrients for themselves and other members of the community; therefore, they are called the producers. There are basically two kinds of autotrophs,
"chemoautotrophs and photoautogrophs. "
Chemautotrophs are bacteria that obtain energy by oxidizing inorganic compounds such as ammonia, nitrites, and sulfides , and they use this energy to synthesize carbohydrates.
Photoautotrophs are photosynthesizers such as algae and green plants that produce most of the organic nutrients for the biosphere.
Heterotrophs, as consumers that are unable to produce, are constantly looking for source of organic nutrients from elsewhere. Herbivores like giraffe are animals that graze directly on
plants or algae. Carnivores as wolf feed on other animals; birds that feed on insects are carnivores, and so are hawks that feed on birds. Omnivores are animals that feed both on plants and
animals, as human.
Detritivores - organisms that rely on detritus, the decomposing particles of organic matter, for food. Earthworms and some beetles, termites, and maggots are all terrestrial detritivores.
Nonphotosynthetic bacteria and fungi, including mushrooms, are decomposers that carry out decomposition, the breakdown of dead organic matter, including animal waste. Decomposers
perform a very valuable service by releasing inorganic substances that are taken up by plants once more