ecology - narajole raj college

Dr. Sukamal Maity, SEM - VI, Paper - DSC - 3: Soil And Biogeography,

(7. Concept of Biosphere, Ecology, Ecosystem, Eco-tone, Community and Biome)

Ecology

Terminology:

1866 German Biologist Ernst Haeckel first coined the term “Ecology”.

Origin of the word…”ecology”

Came from the two Greek word ‘Oikos’ and ‘Logos’

Oikos = Household / House / Nature to live in

Logos = Study of ……

Literally, it means Study of the “house/environment” in which we live.

Definition: E.P. Odum “Ecology is the study of organism at home”

The study of interactions between organisms and their environment.

Ecology is the scientific study of interactions among organisms and between

organisms and their environment.

These interactions determine distribution of organisms and their abundance.

Ecology expresses the richness of the biosphere.

Study of how organisms interact with each other and with their non-living

surroundings.



Ecosystem ecology highlights energy flow and chemical

cycling among the various biotic and abiotic components.

Landscape ecology pacts with collections of ecosystems and

how they are arranged in a geographic region.

Global ecology examines the influence of energy and

materials on organisms across the biosphere.

Organismal ecology studies how an organism’s structure,

physiology, and (for animals) behavior meet environmental

challenges.

Community ecology deals with the whole array of

interacting species in a community,

An individual is any living thing or organism found on the

Earth. A more exact definition of species is a group of

interbreeding organisms that do not ordinarily breed with

members of other groups. Individuals do not breed with



individuals from other groups. Animals, unlike plants, tend to

be very definite with this term because some plants can cross-

breed with other fertile plants.

In the above diagram, you will notice that Gill, the goldfish, is interacting

with its environment, and will only crossbreed with other gold fishes just like

her.

A population is a group of individuals of a given

(same) species that live in a specific geographic area

at a given time. (Example is Gill and his family and

friends and other fishes of Gill’s species) Note that

populations include individuals of the same species,

Populations contain genetic variation within

themselves and between other populations. Even

fundamental genetic characteristics such as

hair/eye/skin colour and size from individual to

individual.

These interaction of different individuals of populations of different

species come together to living in a particular geographical area is

called Community.

Another word, Community consists of the group of populations of

different species living together and interacting with them in a region.



A community is the set of all populations that inhabit a certain area.

Communities can have different sizes and boundaries. These are often

identified with some difficulty.

The community exists within an ecosystem that supports the lives of

species that inhabit it. The ecosystem consists of the community of living

species as well as the non-living environmental factors (air, sunlight, rocks,

ground, etc...) that create the environment for the community.

In the diagram above, note how populations of gold fishes, salmons, crabs

and herrings coexist in a defined location. A great community usually includes

high biodiversity that more complex and stable than a community that has a

low diversity.

Characteristics of a Community

The features within communities are highly variable, and there are a number of

characteristics that can be used as descriptors to distinguish them.

1935 British Ecologist Arthur George Tansley first coined the term

“Ecosystem”.

• Origin of the word… “Ecosystem”

Came from the two Greek word “Eco” meaning “Environment” and “logos”

meaning “Study of ……”

Terminology:

https://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookglossC.html#community



Definition:

An ecosystem includes all the organisms that live in a particular place,

together with their physical environment.

Ecosystems are dynamic entities composed of the biological community and

the abiotic environment.

A community of organisms and its physical environment

An ecosystem refers to all the living organisms and their physical

environment within a given area.

The living component consists of the interacting communities of

animals, plants and microbes;

The non-living component refers to the air, water, rocks, soil and

climate.

Ecosystem functions:

Ecosystems are involved with:

– Populations and their regulation

– Energy use and waste processing

– Nutrient cycling

Ecological relationships develop from satisfying the essential needs of life and

continuation of the species.

– These relationships are manifested in physical (abiotic) and biotic terms.

http://www.physicalgeography.net/physgeoglos/e.html#ecosystem

http://www.physicalgeography.net/physgeoglos/a.html#abiotic



Component of Ecosystem:

Producers:

Absorb solar energy and make organic material from

atoms in the environment.

– Photosynthesis: with sunlight

6CO2+6H20 ---> C6H12O6 +6O2

Component of

Ecosystem

Abiotic (Non Living)

Physical factors

1. Temperature

2. Humidity

3. Light or Heat

4. Atmospheric Pressure

5. Nutrients in soil

Inorganic substances

1. Water

2. Oxygen

3. Carbon dioxide

4. Nitrogen

Organic substances

1. Proteins

2. Carbohydrates

3. Lipids

Biotic (Living)

Producers

Autotrophs (Green Plants)

Chemotrophs

Consumers / Heterotrophs

(Animals)

Herbivores Cornivores Omnivores

Decomposers / Saprotrophs /

Detrivores / Detritus feeders

(Microorganisms)



A. Primary Producers = Autotrophs:

Sunlight is the main energy source for life on Earth.

Organisms that can capture energy from sunlight or

chemicals and use that energy to produce food are

called autotrophs, or primary producers.

The process in which autotrophs capture light energy

and use it to convert carbon dioxide and water into

oxygen and sugars is called photosynthesis.

The process in which autotrophs use chemical energy

to produce carbohydrates is called chemosynthesis.

Photo – autotrophs

Without autotrophs, there would be no life on this

planet

Ex. Plants and Algae

B. Chemoautotrophs:

Autotrophs that get their energy from inorganic

substances or bonds of inorganic molecules such

as salt, Hydrogen Sulfide

Live deep down in the ocean where there is no

sunlight

Ex. Bacteria and Deep Sea Worms



Tube Worms living in Black Smoker

Consumers:

Consume organic matter to provide themselves

with energy and organic matter necessary for

growth and survival.

a. Herbivores (consume plants)

b. Carnivores (consume meat)

c. Omnivores (plants and meat)

d. Detritivores (detritus)



a. Heterotrophs:

Organisms that do not make their own food

Eat ONLY plants

Another term for Heterotroph is consumer

because they consume other organisms in order

to live

Ex. Rabbits, Deer, Mushrooms, Cows,

Elephants, Giraffes

b. Carnivores:

Eat ONLY meat

Ex. – Lions, Tigers, Sharks

c. Omnivores:

Eat BOTH plants and animals

Ex. – Bears and Humans

d. Detritivores:

Food on the tissue (detritus) of dead organisms

(plant or animal)

Ex. – Shrimp, earthworms, dust mites

Scavengers – Consumes the bodies of dead

animals but does not typically kill them itself.

Ex. – Vultures & Crows



Decomposers:

Bacteria and fungi digest organic molecules in detritus

into simpler organic compounds, and absorb soluble

nutrients.

Without decomposers, many compounds would remain

permanently locked up in dead organisms and hence

would be unavailable for (re)use by living organisms.

Decomposers – absorb any dead material and break it

down into simple nutrients or fertilizers.

Ex. – Bacteria and Mushrooms

as

we

Classification of Ecosystem:



Biome:

Terminology:

The term “Biome” was first suggested in 1916 by Clements, originally as a synonym

for biotic community of Möbius (1877). The International Biological Program (1964–74)

projects popularized the concept of biome.

Definition:

A group of ecosystems that have similar

climates and organisms is called a biome.

Examples – Terrestrial Biomes

Tropical Rain Forest

Tropical deciduous forest

Desert

Temperate Forest ( we live here)

Tundra or polar

https://en.wikipedia.org/wiki/Frederic_Clements

https://en.wikipedia.org/wiki/Biotic_community

https://en.wikipedia.org/wiki/Karl_M%C3%B6bius

https://en.wikipedia.org/wiki/International_Biological_Program



A. Terrestrial Biomes:

• Climate

– Largely determines the distribution and structure

of terrestrial biomes.

– Important in determining why particular

terrestrial biomes are found in certain areas.

Terrestrial biomes

– Are often named for major physical or climatic

factors and for their predominant vegetation.

• Vertical layering is an important feature of terrestrial biomes, and in a forest it might consist

of an upper canopy, low-tree layer, shrub understory, ground layer of herbaceous plants,

forest floor, and root layer

• Layering of vegetation in all biomes provides diverse habitats for animals

• Biomes are dynamic and usually exhibit extensive patchiness

b. Savana Biome:

• precipitation and temperature are seasonal

• Grasses and forbs make up most of the ground cover

a. Tropical Biome: Vertical stratification with trees in canopy blocking light to bottom

strata. Many trees covered by epiphytes (plants that grow on other plants).

Climate and Terrestrial Biomes• climographDesert Temperate grassland Tropical forest

Temperate

broadleaf

forest

Coniferous

forest

Arctic and

alpine

tundra

Annual mean precipitation (cm)

An

nu

al m

ea

n t

em

pe

ratu

re (

ºC)

100 200 300 400

30

15

0

15



• Common inhabitants include insects and mammals such as wildebeests, zebras, lions,

and hyenas.

c. Tropical and Temperate Deciduous forest Biome:

• Winters are cool, while summers are hot and humid; significant precipitation falls year

round as rain and snow.

• A mature forest has vertical layers dominated by deciduous trees in the Northern

Hemisphere and evergreen eucalyptus in Australia.

• Mammals, birds, and insects use all vertical layers in the forest.

• In the Northern Hemisphere, many mammals hibernate in the winter.

d. Desert Biome:

• Precipitation is low and highly variable, generally less than 30 cm per year; deserts may be

hot or cold.

• Plants are adapted for heat and desiccation tolerance, water storage, and reduced leaf

surface area.



• Many kinds of snakes and lizards, scorpions, ants, beetles, migratory and resident birds,

and seed-eating rodents; many are nocturnal.

e. Temperate Grassland Biome:

• Found on many continents.

• Winters are cold and dry, while summers are wet and hot.

• Grasses and forbs, are adapted to droughts and fire.

• Native mammals include large grazers and small burrowers.

f. Northern Coniferous Biome:

• Known as taiga, extends across northern North America and Eurasia and is the largest

terrestrial biome on Earth.

• Winters are cold and long while summers may be hot.

• The conical shape of conifers prevents too much snow from accumulating and breaking

their branches.

• Animals include migratory and resident birds, and large mammals.



g. Tundra Biome:

• Covers expansive areas of the Arctic; alpine tundra exists on high mountaintops at all

latitudes.

• Winters are long and cold while summers are relatively cool; precipitation varies.

• Permafrost, a permanently frozen layer of soil, prevents water infiltration.

• Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) and

supports birds, grazers, and their predators.



B. Aquatic Biomes:

• Aquatic biomes

– Account for the largest part of the

biosphere in terms of area.

– Can contain fresh or salt water.

• Oceans

– Cover about 75% of Earth’s surface.

– Have an enormous impact on the

biosphere.

Biosphere / Ecosphere:

Terminology:

The term "biosphere" was coined by

geologist Eduard Suess in 1875, which he defined

as the place on Earth's surface where life dwells.

Origin of the word…”Biosphere”

Come from the Greek word “bios” =

“life”, “sphaira”, “sphere”.

Earth’s organisms live in the biosphere.

The biosphere consists of the parts of the

planet in which all life survives.

The global ecosystem, the sum of all

the planet’s ecosystems.

Ecologists may study different levels of

ecological organization:

Individual organism

https://en.wikipedia.org/wiki/Eduard_Suess

https://en.wikipedia.org/wiki/Earth#Surface



An accumulation of individuals that

belong to the same species and live in

the same area is called a population.

An accumulation of different populations that live together in an area is

referred to as a community.

Represents a highly integrated & interacting zone comprising of atmosphere,

hydrosphere & lithosphere.

Abundant life between 200 meters below oceans surfaces till approx. 6000 meters

above sea surfaces.

Absent at extremes of north & south poles, the highest mountains & at the deepest

oceans majorly due to hostile conditions.

Occasionally spores of fungi & bacteria do occur at great height beyond 8000 meters

but they are not metabolically active & hence represent only dormant life.

The biosphere is one of the four layers that surround the Earth along with the

lithosphere (rock), hydrosphere (water) and atmosphere (air) and it is the sum of all

the ecosystems.

Eco-tone & Edge-effect:

Terminology:

Was coined from a combination of “eco” (logy) plus “–tone”, from the Greek tones or

tension (a place where ecologies are in tension).

Definition:

An eco-tone is a zone of junction or a transitional area between two biomes (diverse

ecosystems).

Another word, the zone of transition along the edges of two adjacent ecological

communities.



Transitional area between two biomes or diverse ecosystems (where two communities meet

& integrate)

Examples: between a field and forest, between forest and

grassland

May appear as a gradual blending of the two

communities across a broad area, or may manifest itself

as a sharp boundary line.

It is the boundary line where two communities meet

and integrate.

May contains some organisms which are entirely

different from that of adjoining communities

Sometimes the number of species & population density

of some of the species is much greater in this zone than

either community, Known as edge effect

Organisms which occur primarily or most abundantly

in this zone are known as edge species.

Characteristics:

It may be narrow (between grassland and forest) or wide (between forest and desert).

It has conditions intermediate to the adjacent ecosystems. Hence it is a zone of

tension.

Usually, the number and the population density of the species of an outgoing

community decreases as we move away from the community or ecosystem.

A well-developed eco-tone contains some organisms which are entirely different

from that of the adjoining communities.

Edge Effect – Edge Species

Terminology:

An “edge” is the boundary or interface between two biological communities or

between different landscape elements.

Definition and Characteristics:

https://www.pmfias.com/environment-ecosystem-components-ecosystem/



Edge effect refers to the changes in population or community structures that occur

at the boundary of two habitats (eco-tone).

Sometimes the number of species and the population density of some of the species

in the eco-tone is much greater than either community. This is called edge effect.

The organisms which occur primarily or most abundantly in this zone are known

as edge species.

In the terrestrial ecosystems edge effect is especially applicable to birds.

For example, the density of birds is greater in the eco-tone between the forest and

the desert.

Refer to the changes in population or community structures that occur at the

boundary of two habitats.

Type of Edge – Effect:

a. Inherent: Natural features stabilize the border location.

b. Induced: Transient natural or human related activities, subject borders to

successional changes over time.

c. Narrow: One habitat abruptly ends and another begins.

d. Wide (eco-tone): Substantial distance separates border from point where physical

conditions and vegetation do not differ from interior of patch.

e. Convoluted: Border is non-linear.

f. Perforated: Border has gaps that host other habitats.



Bibliography:

Chairas, D.D. Reganold, J.P. and Owen, O.S. 2002. National Resource Conservation and

management for a Sustainable Future, 8th edition, Prentice Hall, Lo—glewood

Cliffs.

Dash, M.C., 2001. Fundamental of Ecology, 2nd edition, Tata McGrawHill, New Delhi

Huggett, R. 1998. Fundamentals of Biogeography, Routledge, London.

Kormondy, E.J. 1996. Concept of Ecology, 4th edition, Prentice- Hall, India, New Delhi.

Myers, A. A. and Giller, P.S. (editors) 1988. Analytical Biogeography: an Integrated Approach

to the Study of Animal and Plant Distribution. Chapman and Hall, London.

Young, A. 2000. Land Resource: Now and Future, Cambridge University Press, Cambridge: 332p.

Chapman J.L. and Rens, M.J. 1993. Ecology: Principle and Applications, Cambridge

University Press, Cambridge.

ecology - narajole raj college

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