STUDYQUERIES provides a depth of knowledge about characteristics Of Life. I am alive, as are you. The dog outside my window is barking, and the tree outside my window is also alive. Clouds that are falling snow, however, are not alive. The computer you’re using to read this article is not alive, and neither is the table or chair you’re sitting at. The parts of a chair that are made of wood were once alive, but they are not now.

Burning wood in a fire would also result in the fire not being alive. We defined biology as the branch of science concerned with the study of living organisms in the introduction to biology. That’s a pretty straightforward definition. However, it opens up the possibility of more difficult and more interesting questions: What is life? What is it to be alive?

Life is defined by what? How can we tell what is alive and what isn’t? Almost everyone intuitively understands what it means to be alive. It is surprising, however, how difficult it is to define life precisely. Since this is the case, many definitions of life are operational definitions – they allow us to separate living things from nonliving ones, but they don’t really pin down what life really is. This separation can be achieved by developing a list of properties that are, as a group, unique to living organisms.

The Characteristics of Life

The study of biology examines the structure, function, growth, origin, evolution, and distribution of living things. It is a science that describes organisms, their functions, how species come into existence, and their interactions with each other and with the natural environment. Modern biology is based on four unifying principles: cellular theory, evolution, genetics, and homeostasis.

Characteristics Of Life
Characteristics Of Life

Biological sciences are largely specialized fields of study. Biological sciences include biochemistry, cell biology, microbiology, immunology, genetics, physiology, zoology, ecology, evolutionary biology, and botany. Biochemistry is the study of the molecules that make up life. Cell biology is the study of life on the cellular level. Microscopic organisms are studied in microbiology. Immunology is the study of disease resistance in an organism.

It is the study of how traits are passed from one generation to the next. Physiology is the study of how the human body works. The study of animals is zoology. Ecology is the study of organisms’ interactions with their environment and with each other.

The study of evolution is concerned with how populations and species change over time. Botany is concerned with plants. For each and every field of biology, the four unifying principles are important. Many specialized areas of study are required in applied fields of biology, such as medicine and genetics.

What Is Life?

There is no unanimous agreement among scientists about what makes up life. Many characteristics describe most living things. However, with most of the characteristics listed, We can imagine one or more examples below that seem to break the rule, with something non-living being classified as living or something living being classified as non-living.

The difference between a living thing and a non-living thing goes beyond just one distinguishing feature. A cat moves but so does a car. A tree grows, but so does a cloud. Crystals have structure, but so do cells. Researchers define life by listing characteristics shared by living things. An entity with all of these characteristics is considered to be alive.

An organism is an individual living thing. All living organisms share a number of characteristics. Living organisms include:

  • Respond to their surroundings
  • Growing And Changing
  • Produce offspring and reproduce
  • Complicated chemistry
  • Homeostasis must be maintained
  • They Are Made Up Of Structures Called Cells
  •  Pass Their Traits Onto Their Offspring

A Quick Review Of Characteristics of Life Defined

We began our list of characteristics of life with the cellular organization. This simply means that living things are composed of cells. Essentially, cells are the basis of life. It doesn’t matter if they are plants, animals, fungi, or bacteria. To be alive, something must have cells.

Reproduction is the second factor. To be alive, something must be capable of reproducing itself. Life forms such as humans reproduce sexually, while unicellular life forms like bacteria reproduce asexually. Living things reproduce in either case.

Our third characteristic is metabolism. It may be difficult for some students to grasp this concept. The process of metabolism consists of a series of chemical reactions within the body (or cell). In addition to protein synthesis, chemical digestion, cell division, and energy transformation, these reactions vary in form and function. Because metabolism includes reactions relating to other characteristics, it is sometimes grouped with those other characteristics. We will separate metabolism for our purposes.

The fourth characteristic is homeostasis. Stabilizing the internal environment is known as homeostasis. Consider how our bodies maintain a constant body temperature or how blood sugar levels are maintained. When homeostasis is disrupted and we spike a fever, it’s an indication that something is threatening our life. The same is true for blood sugar. In extreme situations, homeostasis is disrupted, and this is unfortunately fatal. Thus, maintaining homeostasis is an essential characteristic of life.

Heredity is the next topic. Heterogeneity refers to the ability to pass genetic information from one generation to another. When either of your parents has dark eyes and you also have dark eyes, it’s a result of heredity.

In our countdown, the next characteristic is responsiveness to stimuli. An internal or external stimulus triggers this response. You are probably familiar with this already. Sunflowers tilt toward the sun, dogs pant when hot, or trees lose their leaves in the fall when the sun’s intensity decreases. Living things respond to stimuli in some way; to see this, we just need to look.

What Are The 8 Characteristics Of Life And Importance: In Brief With Examples

Life is the subject of biology, but what is it exactly? Although it may sound like a silly question with an obvious answer, it is not always easy to define life. A branch of biology called virology studies viruses, which exhibit some characteristics of living entities, but lack others.

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Though viruses can attack living organisms, cause diseases, and even reproduce, they don’t meet the criteria that biologists use to define life. As a result, virologists aren’t strictly biologists. Similarly, some biologists study the molecular evolution that preceded life; since these events are not biological events, these scientists are also not considered biologists.

Biology has always wondered: What are the shared characteristics that make something “alive”? If we know that something is alive, how do we find meaningful levels of organization within its structure?


The photo shows a light-colored toad covered with green spots. The toad is a highly-organized structure made up of cells, tissues, organs, and organ systems.

Introduction To Biology- Order
Introduction To Biology- Order

Biological organisms are highly organized, coordinated structures composed of one or more cells. Single-celled organisms are surprisingly complex: inside each cell, atoms make up molecules, which in turn make up cellular organelles.

Similar cells form tissues in multicellular organisms. Organs (body structures that have distinct functions) are created by the combination of tissues. Organ systems are formed when organs work together.

Sensitivity or Response to Stimuli

Organisms respond to a wide range of stimuli. For instance, plants can bend toward a source of light, climb on fences and walls, or respond to touch.

In a photograph of the Mimosa pudica, many tiny leaves are connected to a central stem. Four of these stems are connected.

The Leaves Of This Sensitive Plant (Mimosa Pudica) Will Instantly Droop And Fold When Touched. After A Few Minutes, The Plant Returns To Normal.
The Leaves Of This Sensitive Plant (Mimosa Pudica) Will Instantly Droop And Fold When Touched. After A Few Minutes, The Plant Returns To Normal.

When touched, the leaves of this sensitive plant (Mimosa pudica) droop and fold. The plant returns to normal after a few minutes.

Bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). The movement toward a stimulus is considered a positive response, whereas movement away from a stimulus is considered a negative response.

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Single-celled organisms reproduce by first duplicating their DNA, and then dividing it equally as they prepare to divide into two new cells. Multicellular organisms produce specialized reproductive germline cells that initiate new individuals. When an organism reproduces, genes containing DNA are passed along to its offspring. By using these genes, the offspring will be of the same species and will have similar characteristics, such as size and shape.

Growth and Development

About five puppies are being nursed by a mother dog. Three of them are black, one is brown, and one is pale yellow. Their mother is light brown.

Although No Two Look Alike, These Puppies Have Inherited Genes From Both Parents And Share Many Of The Same Characteristics.
Although No Two Look-Alike, These Puppies Have Inherited Genes From Both Parents And Share Many Of The Same Characteristics.

Genes encode specific instructions for how organisms grow and develop. An organism’s genes are responsible for directing cellular growth and development, which ensures that its young will exhibit many of the same characteristics as its parents.


A complex organism requires multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and adapt to environmental stresses. Nutrient transport and blood flow are two examples of internal functions regulated in an organism. The organs (groups of tissues working together) are responsible for carrying oxygen throughout the body, removing waste, delivering nutrients to every cell, and cooling the body.


Polar bears (Ursus maritimus) and other mammals living in ice-covered regions keep their body temperature by generating heat and reducing heat loss through their fur and a layer of fat under their skin.

A Photo Shows A White, Furry Polar Bear
A Photo Shows A White, Furry Polar Bear

To function properly, cells need the right temperature, pH, and concentration of diverse chemicals. These conditions can, however, vary from moment to moment. Through homeostasis (literally, “steady-state”), organisms are able to maintain internal conditions within a narrow range despite environmental changes.

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As an example, an organism must regulate its body temperature through a process called thermoregulation. Polar bears and other organisms that live in cold climates have body structures that allow them to withstand low temperatures and conserve body heat. Fur, feathers, blubber, and fat are among the structures that aid in this type of insulation. In hot climates, organisms have methods (such as sweating in humans or panting in dogs) for shedding extra heat.

Energy Processing

For their metabolic activities, all organisms rely on some form of energy. Energy from the sun is captured by some organisms and converted into chemical energy in food (photosynthesis); others utilize chemical energy in molecules consumed as food (cellular respiration).

A California Condor Perched On A Cliff's Edge. Its Wings Are Extended In Preparation For Flight.
A California Condor Perched On A Cliff’s Edge. Its Wings Are Extended In Preparation For Flight.

On a cliff’s edge, a California condor perches. It extends its wings in preparation for flight.

In order to fly, the California condor (Gymnogyps californianus) uses chemical energy derived from food. Condors are an endangered species in California; this bird has a wing tag that helps biologists identify it.

Levels of Organization of Living Things

Living things follow hierarchical structures that can be examined at all scales, from the smallest to the largest. Atoms are the smallest and most fundamental units of matter. They consist of a nucleus surrounded by electrons. Atoms make up molecules. A molecule is a chemical structure consisting of at least two atoms held together by at least one chemical bond.

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The majority of molecules that are biologically important are macromolecules, which are large molecules that are made by polymerization (a polymer is a large molecule made by polymerizing smaller units called monomers, which are simpler than macromolecules). Macromolecules include deoxyribonucleic acid (DNA), which contains instructions for the structure and functionality of all living organisms.

All Molecules, Including This Dna Molecule, Are Composed Of Atoms.
All Molecules, Including This Dna Molecule, Are Composed Of Atoms.

The molecular model represents a DNA molecule, showing its double helix structure.

The organelles of some cells are aggregates of macromolecules surrounded by membranes. Organelles are small structures found within cells. mitochondria and chloroplasts are examples of organelles, which carry out essential functions: mitochondria produce energy to power the cell, while chloroplasts utilize sunlight to make sugars. Living things are made up of cells; the cell is the smallest fundamental unit of structure and function.

As a result of this requirement, viruses are not considered living: They do not have cells. To make new viruses, they have to invade and hijack a living cell; only then can they obtain the materials they need to reproduce.) Some organisms consist of a single cell and others are multicellular. Prokaryotic and eukaryotic cells are classified according to their structure. Prokaryotes are single-celled or colonial organisms without membrane-bound nuclei or organelles; in contrast, eukaryotes have membrane-bound organelles and a membrane-bound nucleus.

Cells combine to form tissues, which are groups of similar cells performing similar or related functions in larger organisms. Tissues are organized into organs that perform a similar function. Organisms can be found in both animals and plants. The organ system is the higher level of organization in which functionally related organs are grouped. There are many organ systems in mammals.

The circulatory system, for example, transports blood throughout the body and from the lungs; it includes organs such as the heart and blood vessels. All living things are organisms. For instance, each tree in a forest is an organism. In addition to single-celled prokaryotes and single-celled eukaryotes, microorganisms are also considered organisms.

Individuals of a species living within a particular area are collectively known as a population. For instance, a forest may contain many pine trees. They are all representative of the pine tree population in that forest. The areas may be occupied by different populations. In a forest with pine trees, there are flowering plants as well as insects and microbial populations.

A community consists of a collection of populations inhabiting a particular area. Trees, flowers, insects, and other species in a forest form the forest’s community. It is an ecosystem. Ecosystems consist of all the living things present in an area, as well as abiotic, non-living elements, such as nitrogen in the soil and rainwater. In its highest level of organization, the biosphere consists of all ecosystems, representing all zones of life on earth. The term encompasses both land and water, as well as some of the atmosphere.

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What are the 7 characteristics of life?

All living organisms share several key characteristics or functions: order, sensitivity or response to the environment, reproduction, growth and development, regulation, homeostasis, and energy processing. When viewed together, these characteristics serve to define life.

What are the 10 major characteristics of life?

  • Cells and DNA.
  • Metabolic Action.
  • Internal Environment Changes.
  • Living Organisms Grow.
  • The Art of Reproduction.
  • Ability to Adapt.
  • Ability to Interact.
  • The Process of Respiration.
  • Living Creatures Move

What are the 5 main characteristics of life?

  • Cells = Living things have one or more cells.
  • Homeostasis = The maintenance of a relatively stable internal environment.
  • Reproduction = The ability to form a new offspring.
  • Metabolism = The ability to obtain and use. energy for growth and movement.
  • DNA/Heredity = Genetic material that is passed on during reproduction.

What are the 6 main characteristics of life?

To be classified as a living thing, an object must have all six of the following characteristics:

  • It responds to the environment.
  • It grows and develops.
  • It produces offspring.
  • It maintains homeostasis.
  • It has complex chemistry.
  • It consists of cells.

How do you remember the 8 characteristics of living things?

How do you remember the 8 characteristics of living things? Remember the phrase: Remember My Red Hat And Happy Green Coat (R- reproduction, M – metabolism, R – response to stimuli, H – heredity, A – adaptation through evolution, H – homeostasis, G – growth and development, C – cellular organization).