PEOPLE ENVIRONMRNT INTERACTION NOTES
PEOPLE AND ENVIRONMENT INTERACTION
Deals with people and environment, Population is a near permanent group of
interbreeding individuals of a species found in a space or geographical area at a particular
point.
The main factors affecting population are as follows:
(2) Natality (birth rate)
(3) Martality (death rate)
(4) Population dispersal (emigration, immigration, and migration)
(5) Age distribution (pre-reproductive, reproductive, and post-reproductive)
(6) Population growth rate
(7) Carrying resources mainly food, water, space-there are limited resources to support all
life forms.
Population density is number of individuals divided by space. The term environment
is derived from the French word environner. It means ‘to surround’. According to the
Environment (Protection) Act, 1986, environment includes all the physical and biological
surroundings of an organism and their interactions. Environment is defined as the sum of
water, air, and land, and the interrelation-ships that exist among them and with the human
beings, other living organisms, and materials.
ECOLOGY
The term ecology was coined by Ernst Haeckel in 1869. Ecology deals with the study
of organisms in their natural home.
It is the scientific study of the relations that living organisms have with respect to
each other and their natural environment the ecosystems.
It is present at three levels, which are as follows:
(1) The individual organism (how individuals are affected by the environment and how they,
in turn, affect the environment)
(2) The population
(3) The community.
Ecology is defined as the study of ecosystems.
Ecological Footprint: The ecological footprint measures human consumption of natural
resources in comparison to Earth’s ecological capacity to regenerate them. Calculation of the
footprint takes into account our consumption habits both at (i) micro (individual) level. The
objective of its calculation is also to educate people about the need to change our
consumption behaviour to make it more sustainable. Ecological footprint is measured in
global hectares (gha)
Community
A community is an assemblage of all the interacting populations of different species
in a geographical area. It is a complex interacting network of plants, animals, and
microorganisms.
Ecosystem
The term ecosystem was defined by Arthur Tansley in 1935. Ecosystem is a self-
regulating community of living organisms (populations of species), interacting with each
other and their nonliving, physical environment, for example, forest ecosystem and ocean
ecosystem.
Ecotone: An ecotone is the transitional area of vegetation between two different plant
communities, such as forest and grassland. The influence of the two bordering communities
on each other is known as the edge effect.
Biotic Components (Living Components)
Living components in an ecosystem are either the producers or the consumers. They
are also called the biotic components. Producers produce organic components, for example,
plants produce starch, carbohydrates, and cellulose by a process called photosynthesis.
(1) Producers (or Autotrophs) These produce their own food. Green plants produce
food. Green plants produce food through photosynthesis, by combining carbon
dioxide and water with the help of energy in the form of sunlight.
(2) Consumers: Consumers depend upon producers for their food, for example, human
beings and other animals.
They are of the following types:
(a) Herbivores feed on plants, for example, rabbit and insects.
(b) Carnivores are those animals that eat other animals.
(i) Secondary carnivores feed on herbivores, for example, a frog and a small fish.
(ii) Tertiary carnivores feed on other carnivores for example, a snake and a big fish.
(c) Omnivores feed on both plants and animals, for example, humans, rates, and many
species of birds.
(d) Detrivores feed on dead organisms, for example, earthworms, crabs, and ants. The living
beings that feed on dead or decayed organic matter are also called saprophytes. The are
fungi and bacteria.
(3) Decomposers: These are microorganisms that break down organic matter into
inorganic compounds and in this process, derive their nutrition.
In ecology, abiotic components are non-living chemical and physical factors in the
environment that affect the ecosystems.
Examples are water, light, wind, soil, humidity, minerals, and gases.
Trophic Levels and Ecological Pyramids
The trophic levels form a pyramid, with producers at the bottom, then primary
consumers (herbivores), secondary consumers(carnivores), and tertiary carnivores.
Ecological Pyramids-Trophic Levels
The concept of ecological pyramid was developed by Charles Elton. All ecologial
pyramids begin with producers like plants at the bottom and proceed through various trophic
levels such as herbivores (consume plants), carnivores (prey on herbivores), and so on. The
highest level is at the top of the food chain.
There are three types of ecological pyramids, which are as follows:
Pyramid of energy
Pyramid of numbers
Pyramid of biomass
(1) Pyramid of Energy
The pyramid of energy or the energy pyramid describes the overall nature of the
ecosystem. During the flow of energy form one organism to other, there is considerable loss
of energy in the form of heat.
The energy pyramid is always upright and vertical.
This pyramid shows the flow of energy at different trophic level and is maximum at
the lowest trophic level.
It depicts the energy is minimum at the highest trophic level and is maximum at the
lowest trophic level.
(2) Pyramid of Numbers
The pyramid of numbers depicts the relationship in terms of the numbers of
producers, herbivores, and the carnivores at their successive trophic levels. There are three
types of pyramid of numbers, which are as follows:
Upright pyramid of number
partly upright pyramid of number
Inverted pyramid of number
Upright Pyramid of Number This type of pyramid number is found in the aquatic and
grassland ecosystems.
Partly Upright Pyramid of Number It is seen in the forest ecosystem where the
number of producers are lesser in number and support a greater number of herbivores and
which in turn support a fewer number of carnivores.
Inverted Pyramid of Number
This type of ecological pyramid is seen in parasitic food chain where one primary
producer supports numerous parasites, which in turn support more hyperparasites.
(3) Pyramid of Biomass
The pyramid of biomass is more fundamental. They represent the quantitative
relationships of the standing crops.
There are two types of pyramid of biomass, which are as follows:
Upright pyramid of biomass
Inverted pyramid of biomass.
Related to Trophic Levels
Eutrophic: Water bodies having good quantity of minerals and hence supra optimum growth
of plants.
Oligotrophic: Water bodies deficient in minerals and organic growth.
Dystrophic: Water bodies rich in undecomposed organic matter, e.g., bogs and marshy lakes.
Biosphere
There are different types of ecosystems around us, which involve living organisms and
non-living things. If we combine all the ecosystems present on earth, it is called biosphere.
Biomes
The terrestrial portion of biosphere is divided into biomes. They usually have distinct
climates and life forms adapted to that climate.
Habitat
The area or natural environment in which an organism or population normally lives is
called habitat.
Deals with people and environment, Population is a near permanent group of
interbreeding individuals of a species found in a space or geographical area at a particular
point.
The main factors affecting population are as follows:
(2) Natality (birth rate)
(3) Martality (death rate)
(4) Population dispersal (emigration, immigration, and migration)
(5) Age distribution (pre-reproductive, reproductive, and post-reproductive)
(6) Population growth rate
(7) Carrying resources mainly food, water, space-there are limited resources to support all
life forms.
Population density is number of individuals divided by space. The term environment
is derived from the French word environner. It means ‘to surround’. According to the
Environment (Protection) Act, 1986, environment includes all the physical and biological
surroundings of an organism and their interactions. Environment is defined as the sum of
water, air, and land, and the interrelation-ships that exist among them and with the human
beings, other living organisms, and materials.
ECOLOGY
The term ecology was coined by Ernst Haeckel in 1869. Ecology deals with the study
of organisms in their natural home.
It is the scientific study of the relations that living organisms have with respect to
each other and their natural environment the ecosystems.
It is present at three levels, which are as follows:
(1) The individual organism (how individuals are affected by the environment and how they,
in turn, affect the environment)
(2) The population
(3) The community.
Ecology is defined as the study of ecosystems.
Ecological Footprint: The ecological footprint measures human consumption of natural
resources in comparison to Earth’s ecological capacity to regenerate them. Calculation of the
footprint takes into account our consumption habits both at (i) micro (individual) level. The
objective of its calculation is also to educate people about the need to change our
consumption behaviour to make it more sustainable. Ecological footprint is measured in
global hectares (gha)
Community
A community is an assemblage of all the interacting populations of different species
in a geographical area. It is a complex interacting network of plants, animals, and
microorganisms.
Ecosystem
The term ecosystem was defined by Arthur Tansley in 1935. Ecosystem is a self-
regulating community of living organisms (populations of species), interacting with each
other and their nonliving, physical environment, for example, forest ecosystem and ocean
ecosystem.
Ecotone: An ecotone is the transitional area of vegetation between two different plant
communities, such as forest and grassland. The influence of the two bordering communities
on each other is known as the edge effect.
Biotic Components (Living Components)
Living components in an ecosystem are either the producers or the consumers. They
are also called the biotic components. Producers produce organic components, for example,
plants produce starch, carbohydrates, and cellulose by a process called photosynthesis.
(1) Producers (or Autotrophs) These produce their own food. Green plants produce
food. Green plants produce food through photosynthesis, by combining carbon
dioxide and water with the help of energy in the form of sunlight.
(2) Consumers: Consumers depend upon producers for their food, for example, human
beings and other animals.
They are of the following types:
(a) Herbivores feed on plants, for example, rabbit and insects.
(b) Carnivores are those animals that eat other animals.
(i) Secondary carnivores feed on herbivores, for example, a frog and a small fish.
(ii) Tertiary carnivores feed on other carnivores for example, a snake and a big fish.
(c) Omnivores feed on both plants and animals, for example, humans, rates, and many
species of birds.
(d) Detrivores feed on dead organisms, for example, earthworms, crabs, and ants. The living
beings that feed on dead or decayed organic matter are also called saprophytes. The are
fungi and bacteria.
(3) Decomposers: These are microorganisms that break down organic matter into
inorganic compounds and in this process, derive their nutrition.
In ecology, abiotic components are non-living chemical and physical factors in the
environment that affect the ecosystems.
Examples are water, light, wind, soil, humidity, minerals, and gases.
Trophic Levels and Ecological Pyramids
The trophic levels form a pyramid, with producers at the bottom, then primary
consumers (herbivores), secondary consumers(carnivores), and tertiary carnivores.
Ecological Pyramids-Trophic Levels
The concept of ecological pyramid was developed by Charles Elton. All ecologial
pyramids begin with producers like plants at the bottom and proceed through various trophic
levels such as herbivores (consume plants), carnivores (prey on herbivores), and so on. The
highest level is at the top of the food chain.
There are three types of ecological pyramids, which are as follows:
Pyramid of energy
Pyramid of numbers
Pyramid of biomass
(1) Pyramid of Energy
The pyramid of energy or the energy pyramid describes the overall nature of the
ecosystem. During the flow of energy form one organism to other, there is considerable loss
of energy in the form of heat.
The energy pyramid is always upright and vertical.
This pyramid shows the flow of energy at different trophic level and is maximum at
the lowest trophic level.
It depicts the energy is minimum at the highest trophic level and is maximum at the
lowest trophic level.
(2) Pyramid of Numbers
The pyramid of numbers depicts the relationship in terms of the numbers of
producers, herbivores, and the carnivores at their successive trophic levels. There are three
types of pyramid of numbers, which are as follows:
Upright pyramid of number
partly upright pyramid of number
Inverted pyramid of number
Upright Pyramid of Number This type of pyramid number is found in the aquatic and
grassland ecosystems.
Partly Upright Pyramid of Number It is seen in the forest ecosystem where the
number of producers are lesser in number and support a greater number of herbivores and
which in turn support a fewer number of carnivores.
Inverted Pyramid of Number
This type of ecological pyramid is seen in parasitic food chain where one primary
producer supports numerous parasites, which in turn support more hyperparasites.
(3) Pyramid of Biomass
The pyramid of biomass is more fundamental. They represent the quantitative
relationships of the standing crops.
There are two types of pyramid of biomass, which are as follows:
Upright pyramid of biomass
Inverted pyramid of biomass.
Related to Trophic Levels
Eutrophic: Water bodies having good quantity of minerals and hence supra optimum growth
of plants.
Oligotrophic: Water bodies deficient in minerals and organic growth.
Dystrophic: Water bodies rich in undecomposed organic matter, e.g., bogs and marshy lakes.
Biosphere
There are different types of ecosystems around us, which involve living organisms and
non-living things. If we combine all the ecosystems present on earth, it is called biosphere.
Biomes
The terrestrial portion of biosphere is divided into biomes. They usually have distinct
climates and life forms adapted to that climate.
Habitat
The area or natural environment in which an organism or population normally lives is
called habitat.
