The Foundations of Biology

This lesson introduces the basics of biology, including the process researchers use to study science. It also examines the classes of biomolecules and how substances are broken down for energy.

Biology and Taxonomy


The study or science of living things is called biology. Some characteristics, or traits, are common to all living things. These enable researchers to differentiate living things from nonliving things. Traits include reproduction, growth and development, homeostasis, and energy processing. Homeostasis is the body’s ability to maintain a constant internal environment despite changes that occur in the external environment. With so many living things in the world, researchers developed a taxonomy system, which is used for classification, description, and naming. As shown below, there are seven classification levels in the classical Linnaean system.

Specificity increases as the levels move from kingdom to species. For example, in the image the genus level contains two types of bears, but the species level shows one type. Additionally, organisms in each level are found in the level above it. For example, organisms in the order level are part of the class level. This classification system is based on physical similarities across living things. It does not account for molecular or genetic similarities.


Did You Know?
Carl Linnaeus only used physical similarities across organisms when he created the Linnaean system because technology was not advanced enough to observe similarities at the molecular level.


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