• Ecology is the study of organisms and how they
interact with the environment around them.
• An ecologist studies the relationship between living
things and their habitats.
5. • An Ecosystem is a geographic area where plants, animals,
and other organisms, as well as weather and landscape,
work together to form a bubble of life.
• Ecosystems contain biotic or living, parts, as well as abiotic
factors, or nonliving parts.
:- Forest ecosystem includes grass, soil, wind, sunlight, etc.
Ocean ecosystem include fish, coral, rocks at the bottom,
temperature of warter.
Biotic factors include plants, animals, and other
organisms. Abiotic factors include rocks, temperature,
7. TYPES OF ECOSYSTEM
Aquatic ecosystems refer to all such ecosystems
that are primarily located on or inside water
bodies. The nature and characteristics of all living
and non-living organisms in the aquatic system
are determined based on the environment
surrounding their ecosystem. Organisms in these
ecosystems interact with other organisms in
aquatic and terrestrial ecosystems.
Terrestrial ecosystem refers to all such ecosystems
which are mainly located on land. Although the
presence of water in these ecosystems is
measured, they are entirely land-based and exist
on land. More specifically, a low and sufficiently
needed amount of water is located in terrestrial
ecosystems. The low amount of water separates
Aquatic Ecosystem -
Terrestrial Ecosystem -
There are different types of ecosystems based on different
climates, habitats, and life forms.However, all such types generally fall into
one of the following Main two categories :
8. Components of ECOsystem
• Major components of the ecosystem are biotic components and
• Biotic components are like plants, animals and microorganisms
and abiotic components are like light, wind, soil, water, etc.
ENERGY IN AN ECOSYSTEM
• Energy is transferred between organisms in
food webs from producers to consumers.
• The energy is used by organisms to carry out
• The vast majority of energy that exists in
food webs originates from the sun and is
converted (transformed) into chemical energy
by the process of photosynthesis in plants.
12. An Ecological Community is a group of actually or potentially
interacting species living in the same location. Communities are bound
together by a shared environment and a network of influence each species has
on the other. Community ecology is an expanding and rich subfield of ecology.
The community has the following characteristics:
(a) Species Diversity
(b) Growth From and structure
(e) Relative abundance
(f) Trophic structure
15. Frequency is the number of times a plant species occurs in a given number of quadrats. Frequency
is usually expressed as a percentage and is sometimes called a Frequency Index. The concept of
frequency indicates the probability of finding a species in a series of quadrats examined in an area of
Calculating Percentage frequency:-
Percentage frequency is the probability that a species will be found within a single quadrat.
% frequency = (number of quadrats in which the species is found/ Total number of quadrats) x 100
16. Life-form The structure, form, habits, and life history of an organism.
In plants especially characteristic life-forms, in particular morphological features, are associated
with different environments.
This observation has formed the basis of several attempts at life-form classifications of
Raunkier's scheme (1934) is the best-known and most widely applied life-form scheme.
The Three major life forms in a community of life forms:
There are three main types of species that serve as the basis for a community.
These include the foundation
ii. Keystone Species, and
iii. Invasive Species.
In biology, a species is the basic unit of classification and a
taxonomic rank of an organism, as well as a unit of biodiversity.
Other ways of defining species include their karyotype, DNA
sequence, morphology, behaviour or ecological niche. In
addition, paleontologists use the concept of the chronospecies
since fossil reproduction cannot be examined.
Species were seen from the time of Aristotle until the 18th
century as fixed categories that could be arranged in a
hierarchy, the great chain of being. In the 19th century,
biologists grasped that species could evolve given sufficient
19. INVASIVE SPECIES
• An Invasive Species is an introduced organism
that becomes overpopulated and negatively alters
its new environment.
• An example of a native invasive species is the
purple sea urchin which has decimated natural
kelp forests along the northern California coast
due to the historic overhunting of its natural
predator, the California sea otter.
The series of Percentage of all life forms of all plants in a community is called
Biological spectrum indicates the climate of the area and since plants are used in
the analysis of the spectrum , hence it is also known as Phyto-climatic spectrum.
Biological spectrum represents the distribution of various life forms in
percentile manner. 1can prepare biological spectrum of any area by obtaining
the % value of various plant groups.
24. Biotic factors relate to all the living things in the ecosystem. Their
presence and their biological by-products affect the composition
of an ecosystem.
Biotic factors refer to all living organisms from animals and
humans, to plants, fungi, and bacteria.
The interactions between various biotic factors are necessary for
the reproduction of each species and to fulfil essential
requirements like food, etc.
Examples of Biotic Factors:-
• Examples of biotic resources include all the living components
present in an ecosystem. These include producers, consumers,
decomposers and detritivores.
25. Abiotic factors refer to all the non-living, i.e. chemical and physical
factors present in the atmosphere, hydrosphere, and lithosphere.
Sunlight, air, precipitation, minerals, and soil are some examples of
These factors have a significant impact on the survival
and reproduction of species in an ecosystem.
For instance, without an adequate amount of sunlight, autotrophic
organisms may not be able to survive.
Examples of Abiotic Factors:-
Abiotic examples typically depend on the type of ecosystem.
For instance, abiotic components in a terrestrial ecosystem include air,
weather, water, temperature, humidity, altitude, the pH level of soil,
type of soil and more.
Abiotic examples in an aquatic ecosystem include water salinity,
oxygen levels, pH levels, water flow rate, water depth and
A Food Chain is a linear network of links in a food web
starting from producer organisms and ending at an apex
predator species, detritivores, or decomposer species.
A food chain also shows how organisms are related to
other by the food they eat.
Each level of a food chain represents a different trophic
A Food Web is the natural interconnection of food chains and a
graphical representation of what-eats-what in an ecological
community. Another name for food web is consumer-resource
30. The Three Types of Ecological Pyramids include:
1.Pyramid of Number.
2.Pyramid of Biomass.
3.Pyramid of Energy.
A graphical representation in the shape of a
pyramid to show the feeding relationship of
groups of organisms, and the flow of energy
or biomass through the different trophic
levels in a ecosystem.
i. Ecosystem is a natural cycle.
ii. Ecosystem makes the balance of nature.
iii.Human beings are an integral part of
ecological systems and depend on nature for
survival and quality of life.
iv.Save Nature, survive ecosystem, safe