The document outlines the interplay between biotic and abiotic factors within ecosystems, highlighting that biotic components include producers, consumers, and decomposers, while abiotic factors comprise non-living elements like sunlight, water, and temperature. Both sets of factors are interdependent, influencing the structure and function of ecosystems and affecting the survival and reproduction of organisms. Human activities also impact these factors, emphasizing the need for conservation amidst urbanization and environmental changes.

1. BIOTIC AND ABIOTIC
FACTORS
Dr. J. Vardhana
Assistant Professor
Department of Biotechnology
VISTAS

2. • The ecosystem is made up of biotic and abiotic factors.
Abiotic factor comprises non-living components like
sunlight, temperature, water, soil, wind, humidity and
radiations. These are the physical and chemical agents that
ultimately affects the biotic factors. Biotic factor or
components means the living things of an eco-system. It is
also responsible for the different outbreaks of diseases.
Both abiotic and biotic factors work together. It determines
what the ecosystem will look like and the availability of the
ecological niches.

4. • What are Biotic Factors?
• Biotic factors include living things like plants, animals,
bacteria, etc. It is divided into three main groups;
• Producers
• Consumers
• Decomposers

5. • 1. Producers
• Producers are known as autotrophs.
• By the use of inorganic materials and energy, they prepare
their own food.
• It is considered the first life form. It is because, in the early
days of origin, there were no consumers to feed on.
• There are two major classes of producers. They are
• Photoautotrophs
• Chemoautotrophs

6. • a. Photoautotrophs
• They use sunlight as the source of energy and
carbondioxide as the source of carbon.
• They mostly use the pigment, chlorophyll for capturing the
photon from the sun.
• Similarly, there are also pigments like rhodopsin and
carotenoids which are found in some bacteria, algae, and
phytoplankton. They are used for photosynthesis.
• Later they produce essential things like sugar, protein, lipids,
etc.
• Examples: Green plants, green algae, and some bacteria.

7. • b. Chemoautotrophs
• They use chemical agents like hydrogen, iron, and sulfur as
the source of energy.
• They are usually found in places where the plants cannot
grow.
• They are found at bottom of the ocean or in acidic hot
springs.
• They are also involved in nitrogen fixation.
• Example of Chemoautotrophs: Methanogens. They are the
microorganism which are capable of making the methane
gas.

8. • 2. Consumers
• They are also known as heterotrophs.
• They don’t prepare their own food by themselves as the
producers. It includes all the heterotrophs.
• Herbivores: Animals like a cow, buffalo, the goat which depend
directly on plants for food. They are primary consumers.
• Carnivores: Animals like lions, tigers, which are flesh-eating
animals. They depend on the herbivores for food. They are
secondary consumers.
• Omnivores: Animals like dog, cat which eat depend on both the
plants and animals

9. • 3. Decomposers
• They are also known as detritivores.
• They use organic compounds as the source of energy from the producers and consumers.
• In an ecosystem, decomposers play a vital role, as the complex substances are broken down
into simpler forms.
• Such a simpler form can be further utilized again by the other organisms. It includes different
soil bacteria, fungi, worms, and flies.
• When the animals die they get decomposed because of decomposers. Even plants, fruits start
rotting, it’s because of decomposers.
• Decomposers play the important role in metabolizing waste products.
• Example of decomposer: Mushroom
• For example, Composting
• In our daily life, different wastes are obtained from the kitchen.
• The leftover foods, fruits, vegetables, etc.
• They are collected separately and put in a pile.
• After some time, it yields the fertilizer which is organic and of high quality which can be used
in the field.

10. • Example of biotic factors
• 1. Human
• Human plays the vital role either in conservation or the destruction of nature.
Human has got both the positive and negative side. The positive side is humans
can utilize natural resources and conserve the existence of other animals too.
Drastic changes can be made regarding the conservation. But due to rapid
urbanization and industrialization, the emission of excessive carbon dioxide and
carbon monoxide gas, there is depletion in the quality of air.
• 2. Cyanobacteria
• They are the single-celled autotrophic organism which was considered to be the
first living organisms on earth. Using solar energy they convert the organic
compounds into inorganic compounds. They are capable of making oxygen by
using the carbondioxide.

11. • Factors Affecting
• There are different factors of the ecosystem. Directly or
indirectly they depend on each other for their existence.
• Availability of Food
• It is considered to be the limiting factor. When there is a
shortage of food, animals will die due to starvation. For eg:
when the herbivores die, carnivores will also die due to
starvation. The whole ecosystem will be disturbed.

12. • Presence of Predator
• In an ecosystem, to maintain balance, there must be a
balance between prey and predator. When there is an
increased number of predators but prey is few, in such
condition, the prey will disappear. Suppose in a grassland, if
the number of the cattle are more but grassland is few or
supposes if deer is few but tigers are more in number, then
in such condition, grassland and deer will get disappear.

13. • Presence of Parasites
• Parasites are those organisms that harbor or live in other
living organisms like plants and animals for their existence.
We can take an example of the ectoparasites like lice which
are normally present in the untidy hair of children.
Endoparasites like roundworms, hookworms live in the
intestine. Parasites obtain nutrition from the host. For eg,
hookworm results in anemia as it causes the loss of blood.
When parasites lodges inside the host, use the nutrition of
the host, it will result in illness.

14. • Competition between the species
• It’s the law of nature, for their survival and existence, animals need to compete with each
other. Only those species which has the capacity to obtain food will survive, they will
adapt in nature whereas others will eventually die. Back to the theories of evolution, it
suggested short neck giraffes got disappeared whereas only the long-necked giraffes
existed, it’s because of access to food.
• Similarly, in our human body too, there is the presence of normal flora. Not all bacteria
are harmful. Some good bacteria are also present in our body whose presence prevent
the colonization of the pathogens. Such harmful organisms won’t get access to our
bodies.
• There is always competition between the organism either it’s about the microorganisms
or the other animals.
• All the biotic factor they can’t function solely. Directly or indirectly they are dependent
upon one another. All the biotic factors are influenced or affected by the abiotic factor. As
a result, their coordination, shape the ecosystem.

15. • Abiotic Factors-
• What are the Abiotic Factors?
• It is the non-living part of an environment. It includes all the physical
and chemical aspects of an ecosystem.
• These factors may be present in the atmosphere, hydrosphere, and
lithosphere. It contributes to the continuity of life on earth by
supporting the survival and reproduction process.
• The component also depends upon the type of ecosystem.
• For example, Rainfall contributes to tropical rainforest ecosystems,
sand in desert ecosystems and water, salinity, ocean currents,
pressure in the marine ecosystem.

16. • All the factors are interrelated to each other.
• All the biotic components i.e living components are directly or indirectly dependent upon the
abiotic factors. The biotic and abiotic systems work together for maintaining the ecosystem.
• Abiotic factors include:
• Water
• Sunlight
• Temperature
• Soil
• Atmosphere
• pH
• Air Humidity
• Wind
• Elevation

17. • Water
• Water is an essential abiotic factor. Not only plants but animals even tiny micro-
organisms also need water for their survival. In the absence of water, plants will die,
i.e producers will die. Even the plants in the desert require some amount of water.
• Due to dehydration, animals will die. i.e consumers
• In the case of micro-organism, they need water for proper functioning which we call
water activity. We can take a simple example by giving insight into our kitchen. Dry
fruits can be stored for a long time as compared to juicy fruits.
• Among the various factors, the water activity of an organism also plays a vital role in
the spoilage of the different foods.
• If there is no water, life on earth is not possible. So, researchers assume that if water
can be found on other planets, there might be some evidence of life too. Thus, it is
often said, water is life.

18. • Sunlight
• Sunlight is the major source of energy.
• Plants require sunlight for the photosynthesis process. It is
the process by which plants make oxygen and food using
carbondioxide and water and make it available for the
animals.
• The presence of sunlight also affects the breeding cycle in
animals.
• Some animals are nocturnal, that they are active only at
night time. It is due to the sunlight.
• Light also determines the reproductive and migratory

19. • Temperature
• Temperature is an important abiotic factor in an ecosystem.
• With the variations in the temperature, variations occur in the type of plants and animals. For
eg: Yak lives in cold regions where there is low temperature.
• Nature has adjusted the body like the presence of long furs which make it possible to survive.
• Similarly, in the case of microorganisms, depending on the temperature they are classified as
psychrophiles, mesophiles, thermophiles, thermotolerant, extremophiles.
• The presence of microbes in the Yellow stone hot spring to the Antarctic regions suggests that
variations of temperature have evolved various mechanisms, making it suitable for survival.
• The temperature determines the rate of the metabolic reactions. It affects various enzyme-
catalyzed reactions.
• At the higher temperature, enzymes denature but some enzymes are thermostable.
• Example: Taq polymerase isolated from the bacterium Thermus aquaticus can withstand the
higher temperature.
• It is used in the Polymerase chain reaction (PCR). Most of the other enzymes will be denatured
and cannot be functioned well at this temperature.

20. • Soil
• Soil is an important abiotic factor. It is made up of rocks
along with the decomposed plants and animals.
• With the help of the roots, plants acquire the water and
minerals from the soil. Soil are also of various types, whose
nature and composition vary and have different functions.
• The water holding capacity is also determined by its
composition.
• In the aquatic environment, depending upon the
characteristics of the sediment, it determines the type of
the benthic animals

21. • Atmosphere
• Due to the atmosphere, life is sustained on the earth.
• Plants use the carbondioxide when animals use oxygen gas.
• The atmosphere also protects the animals from the harmful UV
radiation from the sun.
• Humans and other animals are susceptible to the damage by harmful
UV radiation.
• On exposure, it may cause some genetic change as well as has the
capacity to trigger skin cancer.
• It looks like a shield that provides protection to the creatures on earth.

22. • pH
• The increase or decrease in pH also affects the living creatures.
• In some parts of the world, there is an increase in acidity due to the increase in
carbon dioxide. It has created an acidic condition.
• Urbanization along with industrial revolutionization is the major factor. Due to the
increase in acidity, it is also found that the shell of the snail has also dissolved.
• Similarly, coral are also unable to survive in an acidic environment.
• In the human body, gastric acid helps in killing the harmful microorganism in the
stomach.
• But, the bacteria Helicobacter pylori has a urease enzyme. It increases the pH so that
it can survive in it. It is the causative agent of peptic ulcer.
• The vagina is slightly acidic in nature. It is maintained by the lactobacilli so that
pathogens may not colonize in it.

23. • Air Humidity
• Humidity means the presence of water vapor in the air.
• Too much of the humid environment can be dangerous to
the organisms.
• Excessive water may disrupt the internal balance in the
organisms in various ways. Changes in pH may also occur.
• In order to counteract this, plants, animals, and
microorganism have got their own strategies. For eg: In
animals, lungs and kidney helps in excess of the water.

24. • Wind
• At the place where wind occurs regularly, plants are a bit different.
They grow closer to the ground to escape from the harsh wind
• Similarly, some plants may use it for their own benefits like
pollination. Dispersal of seed can be done.
• Elevation
• There is a decrease in the temperature as we go up to the higher
altitude. It is also due to the low partial pressure with the increase
in the elevation. At 2 km there is a decrease in the ambient partial
pressure by 20 % and over 50 % at the 6km.

25. • Responses to the Abiotic Factors
• In the case of an unfavorable environment, the living organism uses different
strategies to cope with the stressful condition.
• For eg: Spore forming bacteria like the Bacillus and Clostridium make spores and
protect themselves. Due to the spore, such bacteria can withstand the high
temperature which makes it difficult to kill. So, sterilization of the equipment is
essential during the lab work.
• The normal body temperature of humans is 37 °C. It is maintained by various
activities like sweating in summer and shivering in winter.
• Birds migrate from Siberia to places of Nepal and India. This migratory activity is
done in order to cope with the extreme cold.
• If animals are unable to travel to long-distance as the birds, they undergo
hibernation ( winter sleep by a bear) and aestivation (summer sleep by a snail).