atom
a basic unit of matter that cannot be broken down by normal chemical reactions
The atom is the smallest and most fundamental unit of matter.
biology
the study of living organisms and their interactions with one another and their environments
For example, a branch of biology called virology studies viruses, which exhibit some of the characteristics of living entities but lack others.
biosphere
a collection of all ecosystems on Earth
Communities exist within ecosystems which exist in the biosphere.
cell
the smallest fundamental unit of structure and function in living things
Organisms are highly organized structures that consist of one or more cells.
community
a set of populations inhabiting a particular area
A community is the set of populations inhabiting a particular area.
ecosystem
all living things in a particular area together with the abiotic, nonliving parts of that environment
Communities exist within populations which exist within ecosystems.
eukaryote
an organism with cells that have nuclei and membrane-bound organelles
Single-celled prokaryotes and single-celled eukaryotes are also considered organisms and are typically referred to as microorganisms.
evolution
the process of gradual change in a population that can also lead to new species arising from older species
Biologists refer to this fit as adaptation and it is a consequence of evolution by natural selection, which operates in every lineage of reproducing organisms.
homeostasis
the ability of an organism to maintain constant internal conditions
All living organisms share several key properties such as order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing.
macromolecule
a large molecule typically formed by the joining of smaller molecules
Many molecules that are biologically important are macromolecules, large molecules that are typically formed by combining smaller units called monomers.
molecule
a chemical structure consisting of at least two atoms held together by a chemical bond
Some organisms capture energy from the sun and convert it into chemical energy in food; others use chemical energy from molecules they take in.
organ
a structure formed of tissues operating together to perform a common function
How these specialized cells come together to form organs such as the heart, lung, or skin in organisms like the toad shown in Figure 1. 2 will be discussed later.
organ system
the higher level of organization that consists of functionally related organs
An organ system is a higher level of organization that consists of functionally related organs.
organelle
a membrane-bound compartment or sac within a cell
These in turn make up cell components or organelles.
organism
an individual living entity
It turns out that although viruses can attack living organisms, cause diseases, and even reproduce, they do not meet the criteria that biologists use to define life.
phylogenetic tree
a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both
The evolutionary relationships of various life forms on Earth can be summarized in a phylogenetic tree.
population
all individuals within a species living within a specific area
As an environment changes, natural selection causes the characteristics of the individuals in a population to track those changes.
prokaryote
a unicellular organism that lacks a nucleus or any other membrane-bound organelle
Single-celled prokaryotes and single-celled eukaryotes are also considered organisms and are typically referred to as microorganisms.
tissue
a group of similar cells carrying out the same function
In most multicellular organisms, cells combine to make tissues, which are groups of similar cells carrying out the same function.
applied science
a form of science that solves real-world problems
This question focuses on the differences between two types of science: basic science and applied science.
basic science
science that seeks to expand knowledge regardless of the short-term application of that knowledge
This question focuses on the differences between two types of science: basic science and applied science.
deductive reasoning
a form of logical thinking that uses a general statement to forecast specific results
Deductive reasoning or deduction is the type of logic used in hypothesis-based science.
science
knowledge that covers general truths or the operation of general laws, especially when acquired and tested by the scientific method
The science of biology is very broad in scope because there is a tremendous diversity of life on Earth.
scientific law
a description, often in the form of a mathematical formula, for the behavior of some aspect of nature under certain specific conditions
A scientific law is a description, often in the form of a mathematical formula, of the behavior of an aspect of nature under certain circumstances.
scientific method
a method of research with defined steps that include experiments and careful observation
The scientific method is a method of research with defined steps that include experiments and careful observation.
scientific theory
a thoroughly tested and confirmed explanation for observations or phenomena
Hypotheses, or tentative explanations, are generally produced within the context of a scientific theory.
variable
a part of an experiment that can vary or change
Each experiment will have one or more variables and one or more controls.
These terms were extracted from Concepts of Biology – 1st Canadian Edition by Charles Molnar and Jane Gair, eCampusOntario (originally published by BCcampus) which is licensed under a Creative Commons Attribution 4.0 International License. Chapter content adapted from Concepts of Biology by OpenStax (© Rice University), licensed under CC BY 4.0.