Behavior plays a central role in biology. While understanding it seems intuitive, defining it scientifically is challenging.
Defining Behavior
A barking dog, a singing bird, and a fluttering butterfly are good examples of behavior. However, observing activities throughout the vast range of organisms in the biosphere is one of biology’s grand challenges.
There is more. Geckos’ body coloration perfectly fuses with a tree’s bark pattern to avoid the risk of discovery. While motionless female moths emit scents to attract males, octopuses exhibit complex behaviors, including problem-solving, using tools, and signaling.
Developing standards to quantify and qualify behaviors remains beyond biology’s reach. For this reason, a scientific consensus definition does not exist. However, a recent meta-analysis supports the following vague definition –
“Behavior is the internally coordinated responses (actions or inactions) of whole living organisms (individuals or groups) to internal or external stimuli.”
Behavior, then, can be viewed as any activity of an organism in its biosphere.
Evolution
Behavior may act as an evolutionary cause or effect. While its origins are unknown, an organism’s innate characteristics can change its behavior, morphology, and physiology in response to environmental changes, an ability known as phenotypic plasticity.
Plasticity is the degree the phenotype can change in response to environmental stresses. When the degree of plasticity shifts the function of a trait to serve a different function, the process is called exaptation.
The role of plasticity in evolution, however, is controversial. As Ralf J Sommer of the Max Planck Institute in Germany notes –
“While for more than a century, biologists have proposed this organismal feature to play an important role in evolution and the origin of novelty, the idea has remained contentious.”
Studies
Behavior is complex. Studies on it draw on a range of disciples, including anatomy, morphology, physiology, molecular biology, reproduction, developmental biology, neurology, and ecology.
As in other fields of biology, behavioral studies require objectively testable evidence to be scientific. However, objectively measuring it is more challenging than measuring the speed of light. The physical parameters of light are definable – behaviors are not.
Behavioral evidence to support the theory of evolution is challenging. Like other fields of biology, there must be a scientific demonstration of common ancestry giving rise to “innumerable” transitional links.
Behavior is a subcategory of Evolution and Science that scientifically explores evolution’s validity.
Testing Behavior
To understand how evidence from behavior challenges the theory of evolution, click to read the following posted articles –
- Behavioral Evolution in the Red Fire Ant
- Sharks, No Evolution Forerunner
- The European Eel, Darwin Wrong
- Evolution at an Impasse
- Ant Instincts
Each article describes what evidence was found and why scientifically it undermines the theory of evolution, including Darwin’s.
Darwin Then and Now is an educational resource on the intersection of evolution and science and the challenges facing the theory of evolution.
Refer to the Glossary for the definition of terms.
