1. Chapter 2: Biological Beginnings ©2009 The McGraw-Hill Companies, Inc. All rights reserved. Life-Span Development Twelfth Edition

2.  Natural Selection: an evolutionary process by which those individuals of a species that are best adapted are the ones that survive and reproduce Based on Darwin’s theory Survival characteristics are passed on in genes  Can produce a gradual modification of the population over many generations Survival characteristics may change based on environmental conditions  Adaptive Behavior: behavior that promotes an organism’s survival in the natural habitat ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

3.  Evolutionary Psychology: emphasizes the importance of adaptation, reproduction, and “survival of the fittest” in shaping behavior Fit: the ability to bear offspring that survive long enough to bear offspring of their own  Natural selection favors behaviors that increase reproductive success David Buss is a very influential evolutionary psychologist ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

4.  Extended childhood period allows time to develop a large brain and learn complexity of human society  Many evolved psychological mechanisms are domain-specific Information processing  Evolved mechanisms are not always adaptive in contemporary society ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

6.  Why do humans live so long after reproduction? Perhaps older people improve the survival rate of babies  Paul Baltes: benefits of evolutionary selection decrease with age Natural selection is tied to reproductive fitness Does not weed out harmful conditions that appear among older adults  Increases our need for culture ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

7.  Evolutionary psychology approach is just one theory of many It has its limitations and weaknesses, and its critics  Bidirectional view: environmental and biological conditions influence each other Evolution gives us bodily structures and biological potentialities, but it does not dictate behavior People create behavior in the context of culture ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

8.  Human life begins as a single cell  Nucleus of each cell contains chromosomes Chromosomes: thread-like structures made up of DNA DNA: a complex double-helix molecule that contains genetic information  Genes: units of hereditary information in each chromosome Genes direct cells to reproduce themselves and to assemble proteins  Proteins: building blocks of cells and regulators that direct the body’s processes ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

9.  Every individual carries DNA variations, but most do not display a disorder  Today, many genetic diseases can be detected prior to and immediately after birth However, knowledge of genetic flaws leads to difficult choices about how to manage such information  Genetic counselors help people make reproductive decisions ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

10.  Ultrasound Sonography: high-frequency sound waves used to create a visual representation of fetus’s inner structures  Fetal MRI: magnetic resonance imaging designed to diagnose fetal malformations  Chorionic Villus Sampling: small sample of placenta is removed to detect genetic and chromosomal abnormalities  Amniocentesis: samples amniotic fluid to test for chromosomal or metabolic disorders  Maternal Blood Screening: identifies pregnancies with elevated risk for certain birth defects ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

11.  Infertility: the inability to conceive a child after 12 months of attempting  In Vitro Fertilization (IVF): egg and sperm are combined in a laboratory dish; fertilized egg is transferred to woman’s uterus Success depends on woman’s age Increases risk of multiple births  Higher risk of life-threatening problems  Health risks to mother  Possible psychological effects on children ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

14.  Adoption: an alternative to infertility treatment Children adopted early in life fare better than children adopted later Somewhat more likely to experience psychological and school-related problems than non-adopted children No differences in antisocial behavior or self-esteem Vast majority of adopted children adjust effectively, and most parents are satisfied with their decision to adopt ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

15.  Behavior Genetics: seeks to discover the influence of heredity and environment on individual differences in human traits and development Twin studies: compare identical (monozygotic) twins with fraternal (dizygotic) twins Adoption studies: compare the characteristics of adopted children with their adoptive parents and their biological parents  May also compare adopted and biological siblings ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

16.  Heredity – Environment Correlations: individuals’ genes may influence the types of environments to which they are exposed ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

17.  Shared environmental experiences: siblings’ common experiences  Non-shared environmental experiences: a child’s unique experiences, both within and outside the family Shared environment accounts for little of the variation in children’s personality or interest Heredity influences the non-shared environments through heredity–environment correlations ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

18.  Epigenetic view: development is an ongoing, bi-directional interchange between heredity and environment Heredity and environment operate together ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

19.  The relative contributions of heredity and environment are not additive  Complex behaviors have some genetic loading that gives people a propensity for a particular developmental path  Our environment is complex, and the interaction of heredity and environment is extensive  Much needs to be learned about specific ways in which environment and genetics interact to influence development ©2009 The McGraw-Hill Companies, Inc. All rights reserved.