Introduction to Psychology

Introduction to Psychology

Chapter Two: Biological Influences n Behavior Learning Objectives After completing Unit Two, you will be able to: 1. Describe the biological bases of behavior, by discussing the impact of genetic influences on behavior 2. Describe the impact of evolution on behavior, utilizing five evolution theories and their impact on behavior 3. Discuss environmental influences on behavior 4. Describe the influence of hormones on behavior 5. Describe the hierarchical brain structures and behavioral functions 2.1 Genes, Evolution, and Environment Humans have wondered how physical characteristics are transmitted from parents to their offspring. Many have wondered how genetics influence behavior and how people adapt to their environment. Genetic Influences Early in the 20th century, geneticists made the important distinction between genotype (the specific genetic makeup of the individual), and phenotype (the individual’s observable characteristics). Genes and Heritability 1. Individual Differences- At a biological level, genes direct the process of development by programming the formation of proteinmolecules, which can vary in infinite ways. Heredity potential is carried in the genes and genotype is present from conception. 2. Group Differences- Phenotype can be affected by both genes and the environment. Genetic structure and phenotype are not identical, in part because some genes are dominate while others are recessive and many characteristics are influenced by the interactions of multiple genes.

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