2. Origin of the
word…”ecology”
Greek origin
OIKOS = household
LOGOS = study of…
Study of the “house/environment” in
which we live.
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MSNIMT
3. Ecology is study of
interactions between
non-living components in the environment…
light
water
wind
nutrients in soil
heat
solar radiation
atmosphere, etc.
AND…
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MSNIMT
4. Living organisms…
Plants
Animals
microorganisms in soil, etc.
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MSNIMT
5. To study Ecology
involves…
For non-living For living (biotic)
(abiotic) animal behavior
Climatology Taxonomy
Hydrology Physiology
Oceanography mathematics
Physics (population studies)
Chemistry etc.
Geology
soil analysis, etc.
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MSNIMT
6. Levels of Environmental Organization
Organism
Population
Community
Eco system
Biome
Biosphere
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MSNIMT
7. Organism
Individual refers to a single organism, this
level can include any living organism from a
plant to an animal
Population
All the organisms in an ecosystem
belonging to the same species which live
in one place at one time
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MSNIMT
9. Community
All the populations in an
ecosystem
Community refers to groups
of organisms from different
species living in the same area
interacting with each other
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MSNIMT
10. Ecosystem
All the organisms living in an
area and the nonliving features
of their environment
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MSNIMT
13. Habitat
The place in which an organism
lives. It is the physical location of
community
provides the kinds of food and
shelter, the temperature, and the
amount of moisture the organism
needs to survive
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MSNIMT
16. Competition
Competition caused by
population growth affects many
organisms, including humans
Limits population size
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MSNIMT
18. Limiting Factor
Anything that restricts the
number of individuals in a
population.
Includes living and nonliving
features of the ecosystem
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MSNIMT
20. Succession
Ecological succession was formerly seen as
having a stable end-stage called the climax,
sometimes referred to as the 'potential
vegetation' of a site, shaped primarily by the
local climate.
Natural, gradual changes in the types of
species that live in an area; can be primary or
secondary.
Primary – begins in a place without soil
Secondary – where soil already exists
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MSNIMT
21. Clement's theory of succession/Mechanisms of
succession
F.E. Clement (1916) developed a descriptive theory of succession and
advanced it as a general ecological concept. His theory of succession had a
powerful influence on ecological thought. Clement's concept is usually termed
classical ecological theory. According to Clement, succession is a process
involving several phases:
Nudation: Succession begins with the development of a bare site, called
Nudation (disturbance).
Migration: It refers to arrival of propagules.
Ecesis: It involves establishment and initial growth of vegetation.
Competition: As vegetation became well established, grew, and spread,
various species began to compete for space, light and nutrients. This phase is
called competition.
Reaction: During this phase autogenic changes affect the habitat resulting in
replacement of one plant community by another.
Stabilization: Reaction phase leads to development of a climax community
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MSNIMT
26. Pioneer species
A group of organisms, such as
lichens, found in the primary
stage of succession and that
begin an area's soil-building
process
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MSNIMT
28. Climax community
A community that has reached a stable stage of
ecological succession
According to classical ecological theory, succession
stops when the sere has arrived at an equilibrium or
steady state with the physical and biotic environment.
Barring major disturbances, it will persist indefinitely.
This end point of succession is called climax
The final or stable community in a sere is the climax
community or climatic vegetation. It is self-perpetuating
and in equilibrium with the physical habitat. There in no
net annual accumulation of organic matter in a climax
community mostly. The annual production and use of
energy is balanced in such a community.
Baiju John, Asst.Professor, 28
MSNIMT
29. Characteristics of climax
The vegetation is tolerant of environmental conditions.
It has a wide diversity of species, a well-drained spatial structure, and
complex food chains.
The climax ecosystem is balanced. There is equilibrium between gross
primary production and total respiration, between energy used from
sunlight and energy released by decomposition, between uptake of
nutrients from the soil and the return of nutrient by little fall to the soil.
Individuals in the climax stage are replaced by others of the same kind.
Thus the species composition maintains equilibrium.
It is an index of the climate of the area. The life or growth forms
indicate the climatic type.
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MSNIMT
31. Biome
Large geographic areas with similar climatic
condition on earth .
Some parts of the earth have more or less the
same kind of abiotic and biotic factors spread
over a large area creating a typical ecosystem
over that area. Such major ecosystems are
termed as biomes.
Biomes are defined by factors such as plant
structures (such as trees, shrubs, and
grasses), leaf types (such as broad leaf and
needle leaf), plant spacing (forest, woodland,
savanna), and climate.
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MSNIMT
34. Biosphere
Biosphere is the largest level in ecology, this
level includes all ecosystems on Earth
biosphere is the global sum of all ecosystems. It
can also be called the zone of life on Earth, a
closed (apart from solar and cosmic radiation) and
self-regulating system
The biosphere is the global ecological system
integrating all living beings and their relationships,
including their interaction with the elements of the
lithosphere, hydrosphere and atmosphere.
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MSNIMT
36. Lithosphere
The lithosphere is the rigid outermost shell of a rocky planet.
It comprises the crust and the portion of the upper mantle that
behaves elastically on time scales of thousands of years or
greater
Hydrosphere
A hydrosphere in physical geography describes the combined
mass of water found on, under, and over the surface of a
planet.
Approximately 71% of the Earth's surface, an area of some
361 million square kilometres (139.5 million square miles), is
covered by ocean
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MSNIMT
37. Atmosphere
-The atmosphere of Earth is a layer of gases surrounding the
planet Earth that is retained by Earth's gravity.
-The atmosphere protects life on Earth by absorbing
ultraviolet solar radiation, warming the surface through heat
retention (greenhouse effect), and reducing temperature
extremes between day and night
Ecosphere
-In ecology the term ecosphere can refer to the Earth's
spheres, a planetary ecosystem consisting of the
atmosphere, the geosphere (lithosphere), the hydrosphere,
and the biosphere.
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