Final answer:
Mate selection and response to environmental stressors are two behaviors with major genetic consequences, affecting evolution and potentially leading to heritable phenotypic changes due to natural selection and epigenetic shifts.
Step-by-step explanation:
Genetic Influences on Behavior: Two behaviors that have major genetic consequences are mate selection and response to environmental stressors. Mate selection is heavily influenced by genetics, as individuals often look for traits that enhance the survival and reproduction success of their offspring. This behavior can lead to sexual selection, a form of natural selection. On the other hand, an individual's genetic makeup can significantly dictate their response to environmental stressors, like famine or trauma, potentially leading to inherited changes in gene expression known as epigenetics. These behaviors, therefore, not only affect the individuals themselves but can lead to changes in the gene pool over time, impacting evolution. Genetic diversity is also vital in shaping these behaviors. Through sexual reproduction and genetic mutations, unique combinations of alleles arise, leading to varied behaviors and characteristics across a population. Additionally, behaviors that positively affect an organism's fitness can be favored by natural selection, promoting the proliferation of beneficial genetic traits. Behavioral geneticists use twin and adoption studies to understand how genes and environment contribute to behavioral traits. Epigenetic shifts, due to environmental influences, can lead to heritable phenotypic changes. This intricate interaction between genes and environment demonstrates the complex nature of behaviors and their evolutionary consequences.