What is life in biology?


Article by: Camilla Fezzi, on 21 July 2023, at 06:21 pm PDT

Life, as we understand it, represents an intriguing concept that has attracted the curiosity of biologists, philosophers, and physicists for centuries. From a biological perspective, life is a complex, self-sustaining system that exhibits a set of fundamental characteristics, enabling the distinction between living organisms and inanimate matter. This article will delve into the understanding of life within the context of biology.

Defining Life: The Biological Perspective

While there's no universally agreed-upon definition of life, biologists generally agree that living organisms exhibit certain key traits. These include:

1. Cellular Organization: All living things are composed of one or more cells, which are the basic units of life. Cells are self-contained, bounded by a membrane that separates the inner environment from the external one.

2. Metabolism: Living organisms engage in metabolism – the biochemical reactions that convert nutrients into energy and the building blocks of proteins, nucleic acids, and other complex molecules.

3. Growth and Development: Living organisms grow and develop according to specific instructions coded in their genes. These genes carry information for traits from parents to offspring.

4. Reproduction: Life forms reproduce, creating new individuals either asexually (one parent and usually identical offspring) or sexually (two parents and typically varied offspring).

Reproduction of bacteria by scission
Reproduction of bacteria by scission

5. Response to Stimuli: Living beings react to changes in their environment (stimuli), enabling survival and adaptation.

6. Evolution: Populations of organisms evolve, i.e., change genetically over time. This process allows species to adapt to their environment and leads to biological diversity.

These traits are not exhaustive, and not all are always exhibited by all life forms. Despite this, they provide a solid foundation for understanding what constitutes life.

The Complexity of Life

Life is characterized by a high degree of structural complexity and organization. Each living organism, from the simplest single-celled organism to the most complex multi-cellular one, maintains a precise and constant pattern of organization.

For instance, within each cell, thousands of different types of molecules, including DNA, proteins, lipids, and carbohydrates, interact to carry out the processes necessary for the cell's survival. These processes include energy production, waste disposal, sensing and responding to the environment, and, for some species, self-replication.

In multi-cellular organisms, cells are often specialized to perform specific functions, and different types of cells work together to form tissues and organs, which carry out the organism's functions.

 Life, Energy, and Entropy

One of the distinctive features of life is its relationship with energy. Living organisms extract energy from their environment and use it to maintain their complex, organized state. This process is in apparent defiance of the second law of thermodynamics, which states that systems tend to move towards a state of maximum entropy or disorder.

However, life does not violate this law because it is an open system that constantly exchanges energy and matter with its environment. While life maintains order within its system boundaries, it increases the overall entropy of its surroundings.

 Life and Evolution

Another remarkable aspect of life is its capacity for evolution. Over successive generations, life forms can change in response to environmental pressures, leading to the emergence of new species. This fundamental biological process is responsible for the vast array of life forms and ecological interactions that we see on Earth today.

The theory of evolution by natural selection, first proposed by Charles Darwin, offers the most widely accepted explanation for this phenomenon. It suggests that individuals with traits that increase their survival and reproductive success are more likely to pass these advantageous traits to their offspring.

Understanding life's intricacies remains an immense scientific frontier. 

Here some examples of new reserach in the world of evolution and life

1. Synthetic Biology

Synthetic biology combines biology and engineering to design and construct new biological parts, devices, and systems, or to redesign systems that have been taken from nature. The goal is to create improved biological functions to meet current challenges in health, agriculture, and manufacturing.

2. Astrobiology

Astrobiology is the study of the origin, evolution, and distribution of life in the universe. It seeks answers to whether life exists beyond Earth, how humans can detect it if it does, and what the future holds for life on Earth and other planets.

3. Genomics and Personalized Medicine

Genomics research focuses on the structure, function, evolution, and mapping of genomes, or the entire set of genes within an organism. With the decreasing cost of genome sequencing, researchers can study diseases at a level of detail never before possible, leading to advancements in personalized medicine.

 4. Neurobiology

Neurobiology involves the study of the nervous system, with a particular focus on neuron interactions. Our understanding of the brain and its impact on behavior and cognitive functions still has much room for exploration.

5. Biotechnology

Biotechnology uses biological processes, organisms, or systems to manufacture products intended to improve the quality of human life. With the advent of CRISPR and other gene-editing tools, biotechnology is a rapidly advancing field.

6. Climate Change Biology

Climate change biology examines the impact of human-induced climate change on living organisms and ecosystems. It explores ways to mitigate these effects and help ecosystems adapt to changing conditions.

 7. Aging and Longevity Research

Scientists are studying the biological processes of aging and seeking ways to extend healthy human lifespan. This involves a better understanding of genetics, cell biology, metabolism, and other aspects of life science.

8. Microbiome Research

The human microbiome (all the microorganisms, mainly bacteria, that live in and on human bodies) has been linked to health conditions from obesity to mental health. Understanding these complex communities of microorganisms can shed light on our health and lead to new treatments.

It's important to note that these areas are not isolated; instead, they often overlap and intersect in various ways. For instance, synthetic biology can contribute to aging research by creating new biological parts. Similarly, advancements in genomics can support personalized medicine and microbiome research. The study of life, therefore, is a multi-faceted endeavor. Life in biology is a complex, self-sustaining system that exhibits a unique set of characteristics, including cellular organization, metabolism, growth and development, response to stimuli, reproduction, and evolution. It is a fascinating and intricate phenomenon that continues to captivate scientists. Understanding the concept of life is fundamental to biology, helping us decipher the myriad forms and processes that constitute the living world around us.

Be the first to read what's new in science!