Introduction to Biology

 What is Biology?

    In simple terms, biology is the study of living organisms and their interactions with one another and their environments. Actually, this is a very broad definition because the scope of biology is vast. In fact, biologists may study anything from the microscopic or submicroscopic view of a cell to ecosystems and the whole living planet.

Biology and Life Sciences

Biology is the study of life. When you study biology you will learn about all of the different kinds of living things. You will learn where they live, what they are like, how they depend on each other, and how they behave.

One of the main ideas in biology is that living things depend on each other. They are part of what is called the balance of nature. All living things interact with other living things and with the world they live in. Without these relationships, nothing would survive.

Humans need plants and animals to supply us with food and raw materials, such as wood, oil, and cotton. Plants provide the oxygen in our air.

We have just tried to define biology, which is a life science. While biology remains the centerpiece of the life sciences, technological advances in molecular biology and biotechnology have led to many specializations and interdisciplinary fields. 

Living systems exhibit levels of organisation from molecules to biomes. In addition, all life on earth is dynamic, with various processes maintaining equilibrium at every level of organisation. The life forms we observe today are a result of billions of years of change.

While studying life sciences, you will learn how scientists gather evidence about life using the scientific method in order to form theories to explain what they observe. The scientific method requires scientists to constantly re-examine their understanding, by testing new evidence with current theories and making changes to those theories if the evidence does not meet the test. The scientific method therefore is the powerful tool you will use throughout the sciences.

What is Life Sciences?

Life Sciences is the scientific study of living things from molecular level to the ecosystem level, and involves a study of the interactions of organic molecules to the interactions of animals and plants with their environment. The list below contains some of the various branches of Life Sciences.

• Anatomy (plant and animal)
• Biochemistry
• Biotechnology
• Botany
• Ecology
• Entomology
• Environmental Studies
• Genetics
• Medicine
• Microbiology
• Morphology
• Physiology (plant and animal)
• Sociobiology (animal behaviour)
• Taxonomy

• Zoology

Characteristics of Living Things

Sometimes it is difficult to tell the difference between living and nonliving things. At times, nonliving things have one or more of the characteristics of life, but it is necessary to have all of the characteristics of life to be considered living. Things that have all of the characteristics of life are known as organisms.

All organisms are made of one or more cells. Each cell contains the genetic material DNA that has the information needed to control the life processes of the organism.

What are the characteristics of life?

One of the first things biologists look for when they are searching for characteristics of life is structure, or organization. Whether an organism is made of a single cell or billions of cells, all of its parts work together in an orderly living system.

Another important characteristic of life is reproduction. Reproduction is the ability of an organism to make more of the same type of organism. The new organisms that are made are called offspring. Although reproduction is not needed for the survival of an individual organism, it must occur for the continuation of the organism’s species.

A species (SPEE sheez) consists of a group of organisms that can mate with each other and produce offspring that are able to reproduce. For example, there are many species of crocodiles including the American crocodile, the Australian freshwater crocodile, and the saltwater crocodile. American crocodiles reproduce only American crocodiles. Without reproduction, the species would die out.

Another characteristic of life is that growth and development must take place. An organism begins life as a single cell. As time passes, it grows and develops. As growth and development take place, the organism takes on the characteristics of its species. Growth results in the formation of new structures and an increase in the amount of living material. Development refers to the changes that occur in each organism’s life.

One more characteristic of life is the ability to adjust to surroundings, or the environment. Anything in the environment— air, water, temperature, weather, other organisms—that causes the organism to react is called a stimulus (plural, stimuli). The organism’s reaction to the stimulus is called a response.

An organism also has the ability to control its internal environment in order to maintain conditions suitable for survival. For example, an organism must make constant adjustments to maintain the right amount of water and minerals in its cells. This ability is called homeostasis (hoh mee oh STAY sus). Without the ability to adjust to internal changes, an organism would die.

How do organisms respond to change?

Organisms use energy to grow, develop, respond to stimuli, and maintain homeostasis. Energy is the ability to cause change. Organisms get their energy from food.

Any behavior, structure, or internal process that allows an organism to make changes in response to environmental factors and live long enough to reproduce is called an adaptation (a dap TAY shun).

For example, the leaves of many desert plants have a thick, waxy coating. This is an adaptation that helps these plants conserve water. Having large eyes is an adaptation that lets owls see well at night. The gradual change in a species over time due to adaptations is called evolution (e vuh LEW shun).