What is Life Science?

The life sciences is the branches of science that involve the scientific study of organisms – such as microorganisms, plants, and animals including human beings – as well as related considerations like bioethics.
Introduction
• All the plants and animals are alive or living things.
• The most important criterion to decide whether something is alive or not is the movement.
• The movements in animals are fast and can be observed easily but the movements in plants are
slow and observed with difficulty.
• Animals can move from one place to another or they can move their body parts.
• The plants can only move parts of their body such as leaves, flowers, roots and shoots.

Some life sciences focus on a specific type of life. For example, zoology is the study of animals, while botany is the study of plants. Other life sciences focus on aspects common to all or many life forms, such as anatomy and genetics. Yet other fields are interested in technological advances involving living things, such as bio-engineering. Another major, though more specific, branch of life sciences involves understanding the mind – neuroscience.

The life sciences are helpful in improving the quality and standard of life. They have applications in health, agriculture, medicine, and the pharmaceutical and food science industries.

Life Processes

The basic functions performed by living organisms to maintain their life on this earth are called life processes.

Basic life processes common to all living organisms are:

Basic life processes Function

Nutrition Taking of food inside the body and converting it into smaller molecules which can be
absorbed by the body.

Respiration The process which releases energy from the food absorbed by the body.

Transport The process in which a substance absorbed or made in one part of the body is moved to
other parts of the body.

Excretion The process in which the waste materials produced in the cells of the body are removed
from the body.

Control and coordination A process which helps the living organisms to survive in the changing
environment around them.

Growth The process involves the changes from a smaller organism to a big organism.

Movement The organism either moves from one place to another or moves its body parts.

Reproduction The process involves the making of more organisms form the existing once.

All the living organisms need energy to perform various life processes. They get this
energy from food. Food is a kind of fuel which provides energy to all the living organisms.

Nitrogen Cycle

Nitrogen makes up 78 percent of Earth’s atmosphere. It’s also an important part of living things. Nitrogen is found in proteins, nucleic acids, and chlorophyll. The nitrogen cycle moves nitrogen through the abiotic and biotic parts of ecosystems. Figure below shows how nitrogen cycles through a terrestrial ecosystem. Nitrogen passes through a similar cycle in aquatic ecosystems.

Even though nitrogen gas makes up most of Earth’s atmosphere, plants cannot use this nitrogen gas to make organic compounds for themselves and other organisms. The two nitrogen atoms in a molecule of nitrogen gas are held together by a very stable triple bond. This bond must be broken for the nitrogen to be used. The nitrogen gas must be changed to a form called nitrates, which plants can absorb through their roots. The process of changing nitrogen gas to nitrates is called. It is carried out by nitrogen-fixing bacteria. The bacteria live in soil and roots of legumes, such as peas.

When plants and other organisms die, decomposers break down their remains. In the process, they release nitrogen in the form of ammonium ions. This process is called  Nitrifying bacteria change the ammonium ions into nitrites and nitrates. Some of the nitrates are used by plants. The process of converting ammonium ions to nitrites or nitrates is called nitrification. Still other bacteria, called denitrifying bacteria, convert some of the nitrates in soil back into nitrogen gas in a process called  The process is the opposite of nitrogen fixation. Denitrification returns nitrogen gas back to the atmosphere, where it can continue the nitrogen cycle.