Abiotic Factors- Definition, Types, Examples and Responses

Our environment, the place where we human beings, as well as many creatures, live, is actually made up of or influenced by various factors. These factors have made the earth a home for all of us. This ecosystem is maintained and balanced by the two main factors. i.e. abiotic factor and biotic factor.

Abiotic: non-living factor
Biotic: Living factor

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. 

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

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.

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 activities.

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. 

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 

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.

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. 

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.

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.

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).

References and Sources

1. https://byjus.com/biology/biotic-and-abiotic/
2. https://microbenotes.com/biotic-vs-abiotic-factors/
3. https://www.toppr.com/guides/chemistry/environmental-chemistry/abiotic-factors/
4. https://www.nationalgeographic.org/encyclopedia/abiotic-factors/ 
5. https://www.examfear.com/notes/Class-12/Biology/Organisms-and-Populations/2544/Major-abiotic-factors-of-the-ecosystem.htm
6. https://www.examfear.com/notes/Class-12/Biology/Organisms-and-Populations/2545/Responses-to-Abiotic-Factors.htm 
7. https://alevelbiology.co.uk/gcse/ecosystem-abiotic-biotic-factors/