Individual or Organism
- The basic living system, a functional grouping of the lower-level components,
including at least one cell
- Example – plant, animal, bacteria, fungi etc.
- As you have seen in the above diagrams individual’s body is made up of organs,
organelles which help in carrying out various processes of life.
- A population is a group of organisms of same species, which live in a particular
geographical area, and have the capability of interbreeding.
- The individuals in a population competes or share for similar resources and
- Example – teakwood trees in forest, bacteria in a culture plate, lotus plants in a
- An organism cannot survive without interacting with other organisms and so we never see a plant or animal seldom occur by themselves.
- Example – Animals need plants as their food and plants need animals in pollination,
seed dispersal, and soil microorganism for micronutrient supply and thus the two need each other.
- Mostly communities are named after the dominant species. Example – grassland
community is dominated by grasses, though it may contain herbs, shrubs and trees.
- Communities are not fixed or rigid. They can be small or large. Like human community is so large while tiger community is too small.
Types of community –
On the size of community, we can classify the community as follows –
1. Major community
2. Minor community
Major community – these communities are –
- Large sized
- Well organized
- They need not any input or output from any adjacent community. But they depend only on the Sun’s energy.
- Example – Tropical evergreen forest
Minor community – unlike major community these communities are –
- Dependent on neighboring communities and so many times are also known as societies.
- They are dependent because they are secondary aggregations within a major community.
- Example – a mat of a lichen on a cow dung pad.
Structure of a community –
- The structure of a community is its characteristics and that are determined by environmental factors.
Characteristics of community –
- Type of area inhabited by them
- Diversity of species
- An ecosystem is a community of living organisms in conjunction with the nonliving
components of their environment (things like air, water and mineral soil), interacting
as a system.
- By this example we can understand the concept of ecosystem. It performs all the
processes of an ecosystem i.e. productivity, decomposition, energy flow and
o Abiotic component – water with dissolved organic and inorganic substances
and rich soil deposit. Sunlight, temperature, day-length and other climatic
conditions regulate the functioning of entire period.
o Autotrophic components – Phytoplankton, algae, floating, submerged and
o Consumers – zooplankton, free swimming, and bottom-dwelling forms.
o Decomposers – fungi, bacteria, and flagellates
o This system also performs all the functions of any ecosystem and of a
biosphere as a whole i.e. conversion of inorganic material into organic with
the help of energy of sun by autotrophs. Consumption of heterotrophs by
autotrophs. Decomposition and mineralization of dead matter for nutrient
- It is a complex set of the relationship among Living organisms, habitats, and residents of an area.
- Ecosystems vary in sizes but functions of an ecosystem remain the same. Example –
pond ecosystem and ocean system vary in sizes but have the same functions.
- If one part of an ecosystem damages it has an impact on everything else.
- When an ecosystem is healthy all its elements are live in balance and are capable of
Components of ecosystem
Components of ecosystem and environment are same.
1. Abiotic components –
- These are inorganic and non-living things. It consists of soil, air water, light, etc. Large no. of chemicals and physical processes like an earthquake, volcanoes are also part of it.
- These components play a major role in deciding where and how an organism will live in their environment.
- It is necessary for the maintenance of life. For plants, the sun is a source of energy and since plants cannot use this energy from the sun they eat plants and gets energy from themselves.
- Water is essential for all living organisms and especially for our body which consists
of 70% water and helps in regulating temperature. It is also a habitat for many
organisms like fish, frog, etc.
- It is a very important factor in our environment. As you can see that they decide our
climate, vegetation, even our body also tries to maintain constant body
- It is also one of the factors which helps in survival of an organism by important gases, protecting from sun’s harmful rays, etc. it is made up of – Nitrogen – 78%, Oxygen – 21%, CO2 – 0.038% and inert gases (Argon – 0.39%, Neon etc.)
- The land is covered by soil and a wide variety of microbes, protozoa, fungi and small
animals (invertebrates) thrive in it. Roots of plants pierce through the soil to tap
water and nutrients.
- Organisms can be terrestrial or aquatic. Terrestrial animals live on land. Aquatic
plants, animals, and microbes live in freshwater as well as in the sea. Some microbes
live even in hot water vents under the sea.
- Inorganic compounds – carbon, carbon dioxide, nitrogen, water, nitrates, ion of
various metals are necessary for the survival of organisms.
- Organic compounds – proteins, carbohydrates, lipids, fats are made from the decomposition of inorganic compounds.
g) Latitude and altitude
- Different climates like tropic, subtropical, tundra on earth are determined by latitude and other factors. And these climate decides what kind of vegetation would be there.
2. Biotic components
It consists of living organisms like plants, animals, microbes. They are classed into
producers and consumers according to their functional attributes.
- a) Primary producers – autotrophs (self –nourishing)
These are basically green plants and certain bacteria and algae.
They make their food (carbohydrate) on own by using carbon dioxide, water in the
presence of sunlight. This process is called as photosynthesis.
In terrestrial ecosystem – herbaceous and woody plants are producers.
In the aquatic ecosystem – various species of microscopic algae.
b) Consumers – Heterotrophs or phagotrophs
They depend on others for food i.e. not capable of producing their own food.
They can be divided into 2 broad categories – Macroco nsumers and Micro
They feed on plants or animals or both.
Herbivores are primary consumers which feed mainly on plants e.g. cow, rabbit.
Secondary consumers feed on primary consumers e.g. wolves.
Carnivores which feed on secondary consumers are called tertiary consumers e.g.
lions which can eat wolves.
Omnivores are organisms which consume both plants and animals e.g. man, crow,
Micro consumers – Saprotrophs (decomposers or osmotrophs)
Detritivores (e.g., earthworm) break down detritus (dead organic substances) into
The products of decomposition such as inorganic nutrients which are released in the ecosystem are reused by producers i.e. plants and thus recycled.
Earthworm and certain soil organisms (such as nematodes, and arthropods) are
detritus feeders and help in the decomposition of organic matter
- Ecotone is the place where two diverse ecosystems meet together.
- Example – a meeting of pond ecosystem and terrestrial ecosystem.
Characteristics of ecotone
- It can be wide or narrow.
- Because it is an intermediate zone of the 2 ecosystem. 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 ecotones contain some organisms which are entirely different from that of the adjoining communities.
Edge effect and Edge species
- There would be a specie whose number and population would be dominating on other communities in that zone. This is a calledEdge effect. And the species which are abundant are called asEdge species.
- In the terrestrial ecosystems edge effect is especially applicable to birds. For example, the density of birds is greater in the mixed habitat of the ecotone between the forest and the desert.
- For example – The Keoladeo Ghana national park forms an ecotone between the hilly forests of Aravalli’s and the Thar Desert, which is situated in the northwest.
- The function or position of a species within an ecological community OR it is the role the species plays, and includes the type of food it eats, where it lives, where it reproduces, and its relationships with other species.
- A species’s niche includes the physical environment to which it has become adapted as well as its role as producer and consumer of food resources.
- A niche is unique for a species, which means no two species have exact identical niches. Niche plays an important role in the conservation of organisms.
- If we have to conserve species in its native habitat we should have knowledge about the niche requirements of the species and should ensure that all requirements of its niche are fulfilled.
Types of Niches
1. Habitat niche – where it lives
2.Food niche – what is eats or decomposes & what species it competes with
3.Reproductive niche-how and when it reproduces.
4.Physical & chemical niche – temperature, land shape, land slope, humidity & other
Difference between Niche and environment
|The role an organism plays in the|
environment (Its “job” in the community)
|Place where an organism lives.|
- Biosphere, which is one of the levels of organizations in ecology, has many divisions
and each division is known as Biome.
- Each biome has a different climate, vegetation, animals and soil type. No 2 biomes are the same.
- Climate, vegetation, animals decide the boundaries of biomes.
- Most important climatic factors are – temperature and precipitation.
Northern most region adjoining the ice bound poles.
Devoid of trees.
Exception – stunted shrubs in the southern part of tundra biome.
Ground flora – lichen, mosses and sedges.
Reindeer, arctic fox, polar bear, snowy owl, lemming, arctic hare, ptarmigan.
Reptiles and amphibians – absent.
Northern Europe, Asia and North America.
Temperature – Moderate than tundra.
Also known as boreal forest.
Dominating vegetation – Coniferous evergreen mostly spruce, with some pine and firs.
Small seed eating birds, hawks, fur bearing carnivores, little mink, elks, puma, Siberian
tiger, wolverine, wolves etc.
Temperate Deciduous Forest
Extends over Central and Southern Europe, Eastern North America, Western China,
Japan, New Zealand etc.
Temperature – Moderate average
Precipitation – abundant rainfall.
Most productive agricultural areas of the earth.
Trees – beech, oak, maple, cherry.
Familiar vertebrates and invertebrates
Tropical rain forest
Temperature – high
Rainfall – high
These forests cover about 7% of earth’s surface with 40% of world’s planet and animal
Vegetation has stratification (Vertical distribution of different species occupying
different levels is called stratification).
Insects (like butterflies and beetles), arachnids (like spiders and ticks), worms, reptiles
(like snakes and lizards), amphibians (like frogs and toads), birds (like parrots and
toucans) and mammals (like sloths and jaguars).
Tropical region – most extensive in Africa.
Grasses with scattered trees and fire resisting thorny shrubs.
Great diversity of grazers and browsers like antelopes, buffaloes, zebras, elephants and
North America, Ukraine, etc.
Temperate conditions with rather low rainfall.
Grasses dominate the vegetation.
Large herbivores like bison, antelope, cattle, rodents, prairie dog, wolves, and a rich and
diverse array of ground nesting bird.
Rainfall – very low and sporadic
Humidity – low
Hot days and cold nights.
Drought resistance vegetation such as cactus, euphorbias, sagebrush.
Reptiles (snakes, lizards), Mammals and birds.