How do environmental changes affect inherited behavioral responses in a species?

In biology, the idea that behavioral responses are strictly "innate" or "blind instincts" is considered an oversimplification. Modern research demonstrates that all behaviors result from a continuous, complex interaction between an organism's inherited genetic material and the environment in which those genes are expressed.12

Environmental changes affect these inherited responses in several ways:

• Modulation of Gene Expression: Environmental conditions—both prenatal and postnatal—can influence how genes are activated. For example, the hormonal environment in the uterus can modulate the development of aggression-promoting brain regions in mice, even when the underlying genetic predisposition is present.1
• Developmental Plasticity: An animal's environment during growth significantly shapes its adult behavior. Factors such as food deprivation, social isolation, or the quality of maternal care can alter behavioral outcomes, sometimes overriding or intensifying inherited tendencies.1
• Learning and Conditioning: Experiences, such as the outcomes of social interactions (victory or defeat), trigger neuroendocrine changes or learning processes that modify future behavior. This demonstrates that even species with strong genetic predispositions rely on environmental input to refine their behavioral repertoire.12

Ultimately, genes steer the development of behavior, but the environment determines how those traits are realized in the individual.23