Evolution and Genetics Basis of Behavior Psychology PDF

**KOLEHIYO NG LUNGSOD NG DASMARIÑAS Psychology Department** *Brgy. Burol Main Dasmariñas, City, Cavite* **LESSON 2** **EVOLUTION AND GENETICS BASIS OF BEHAVIOR** Week 3 Handout +-----------------------------------------------------------------------+ | **Learning Outcomes**...

**KOLEHIYO NG LUNGSOD NG DASMARIÑAS Psychology Department** *Brgy. Burol Main Dasmariñas, City, Cavite* **LESSON 2** **EVOLUTION AND GENETICS BASIS OF BEHAVIOR** Week 3 Handout +-----------------------------------------------------------------------+ | **Learning Outcomes** | +=======================================================================+ | 1\. Apply the concepts of heredity in psychology. | | | | 2\. Identify and explain different mechanisms of heredity. | | | | 3\. List down and explain different genetic abnormalities. | +-----------------------------------------------------------------------+ **APPLICATION OF HEREDITARY IN PSYCHOLOGY** ❖ Heredity is a fundamental concept in psychology that examines how genetic factors influence behavior, personality, intelligence, and susceptibility to psychological disorders. **Francis Galton**, a 19th-century English polymath who is often considered the ***father of eugenics***. ▪ **Eugenics** -- coined the term \"eugenics\" in 1883, defining it as the science of improving human populations by controlled breeding to increase the occurrence of desirable heritable characteristics. o **Positive Eugenics:** Encouraged the reproduction of people with perceived desirable traits, such as intelligence, physical health, and moral character. o **Negative Eugenics:** Discouraged or prevented the reproduction of people with perceived undesirable traits, such as mental illness, physical disabilities, and criminal tendencies. ***Physiological/Biological Psychology*** **Genetic Inheritance:** Genes are passed from parents to offspring, determining a wide range of characteristics, from physical traits to behavioral tendencies. Genetic predispositions can increase the  likelihood of developing mental health disorders such as depression, schizophrenia, and anxiety disorders. However, environmental factors often trigger the onset of these conditions. **MECHANISMS OF HEREDITY** ❖ Heredity is the process through which genetic information is transmitted from parents to their offspring, ensuring that offspring inherit traits from both parents. This process is governed by the principles of genetics. **DNA Structure and Function** **DNA (Deoxyribonucleic Acid):** The molecule that carries genetic information in all living organisms. It is composed of nucleotides arranged in a double helix structure. **Genes:** Segments of DNA that code for proteins, which carry out most of the functions in a cell. Genes are the basic units of heredity. **Alleles:** Different versions of a gene that can lead to variations in a trait (e.g., blue eyes vs. brown eyes). An individual inherits two alleles for each gene, one from each parent. Reference: Freberg, L. (2010). *Discovering Biological Psychology* (2nd ed.). Wadsworth, Cengage Learning. **Prepared by: Dianne E. Agana, MAPsy, RPm** **KOLEHIYO NG LUNGSOD NG DASMARIÑAS Psychology Department** *Brgy. Burol Main Dasmariñas, City, Cavite* **Polygenic Inheritance** **Complex Traits:** Many traits, such as height, skin color, and intelligence, are influenced by multiple genes (polygenic inheritance) rather than a single gene. These traits exhibit a range of phenotypes, creating a continuous distribution (e.g., a bell curve for height). **Gene-Environment**  **Interactions:** The expression of polygenic traits can be influenced by environmental factors, such as nutrition, stress, and education. **THE PROCESS OF REPRODUCTION** Reproduction is the biological process by which new individuals are produced, involving the transmission of genetic material from parents to offspring. The process is key to the continuity of species and the inheritance of traits. **Meiosis** is a type of cell division that reduces the chromosome number by half, resulting in the formation of haploid gametes (sperm and eggs). Meiosis consists of two rounds of division: Meiosis I and Meiosis II. o **Genetic Variation:** Meiosis introduces genetic variation through two key processes: crossing over (exchange of genetic material between homologous chromosomes) and independent assortment (random distribution of chromosomes to gametes). o **Stages of Meiosis** ▪ **Prophase I:** Chromosomes condense, homologous chromosomes pair up, and crossing over occurs. ***Physiological/Biological Psychology*** ▪ **Metaphase I:** Paired homologous chromosomes align at the cell\'s equator. ▪ **Anaphase I:** Homologous chromosomes are pulled to opposite poles. ▪ **Telophase I:** Two haploid cells are formed, each with half the number of chromosomes. ▪ **Meiosis II:** Similar to mitosis, where sister chromatids are separated, resulting in four genetically unique haploid cells. **Fertilization** is the union of a sperm cell and an egg cell to form a zygote, which contains the full diploid number of chromosomes (46 in humans). o **Zygote Formation:** The zygote undergoes multiple rounds of cell division (mitosis) to develop into an embryo. The genetic material from both parents combines to create a unique genetic profile in the offspring.  Reference: Freberg, L. (2010). *Discovering Biological Psychology* (2nd ed.). Wadsworth, Cengage Learning. **Prepared by: Dianne E. Agana, MAPsy, RPm** **KOLEHIYO NG LUNGSOD NG DASMARIÑAS Psychology Department** *Brgy. Burol Main Dasmariñas, City, Cavite* **Examples of Reproductive Processes** **Human Reproduction:** In humans, the process of reproduction involves the production of sperm in males (spermatogenesis) and eggs in females (oogenesis), followed by fertilization, implantation, and development of the fetus. **Genetic Disorders:** Errors in meiosis or fertilization can lead to genetic disorders, such as Down syndrome (trisomy 21), where an individual has an extra chromosome. **CHROMOSOMAL ABERRATIONS** ❖ Chromosomal aberrations refer to changes in the structure or number of chromosomes, which can result in genetic disorders or developmental abnormalities. These aberrations can occur due to errors during cell division or damage to chromosomes. **Types of Chromosomal Aberrations** **1. Deletion** is a segment of a chromosome that is missing or deleted, leading to the loss of genetic material. **2. Duplication** is a segment of a chromosome that is duplicated, resulting in extra genetic material. **3. Inversion** is a chromosome segment that breaks off, flips around, and reattaches, reversing the order of genes. Inversions can be **paracentric** (involving one arm) or **pericentric** (involving both arms, including the centromere). **4. Translocation** is a segment from one chromosome is transferred to another chromosome. This can be **reciprocal** (exchange of segments between two chromosomes) or **Robertsonian** (fusion of two acrocentric chromosomes). **5. Aneuploidy** is an abnormal number of chromosomes due to nondisjunction during meiosis, resulting in cells with extra or missing chromosomes. **Detection and Diagnosis** **1. Karyotyping:** A laboratory technique that produces an image of an individual\'s chromosomes, allowing for the detection of large chromosomal abnormalities, such as aneuploidies and large deletions or duplications. ***Physiological/Biological Psychology*** **2. FISH (Fluorescence in Situ Hybridization):** A technique that uses fluorescent probes to bind to specific DNA sequences on chromosomes, allowing for the detection of small deletions, duplications, and translocations. **3. Comparative Genomic Hybridization (CGH):** A molecular technique that compares the DNA of a patient with a reference sample to identify gains and losses of DNA segments across the genome. **Examples of Chromosomal Disorders** **[Down Syndrome (Trisomy 21])** **Cause**: An extra copy of chromosome 21. **Symptoms**: Intellectual disability, characteristic facial features (such as a flat facial profile, upward slanting eyes, and a small nose), heart defects, and an increased risk of certain medical conditions like leukemia and Alzheimer's disease. **[Turner Syndrome (Monosomy X)]**  **Cause**: Females have only one X chromosome (45, X). **Symptoms**: Short stature, webbed neck, broad chest, underdeveloped secondary sexual characteristics, and infertility. Some individuals may have heart defects or learning difficulties, particularly with spatial reasoning**.** Reference: Freberg, L. (2010). *Discovering Biological Psychology* (2nd ed.). Wadsworth, Cengage Learning. **Prepared by: Dianne E. Agana, MAPsy, RPm** **KOLEHIYO NG LUNGSOD NG DASMARIÑAS Psychology Department** *Brgy. Burol Main Dasmariñas, City, Cavite* ***Physiological/Biological Psychology*** **[Klinefelter Syndrome (XXY) ]** **[Edwards Syndrome (Trisomy 18) ]** **Cause**: Males have an extra X chromosome (47, XXY). **Symptoms**: Tall stature, reduced muscle mass, body hair, and testosterone levels, infertility, and learning disabilities, particularly with language and reading. Individuals may also have a higher risk of developing certain health issues, such as osteoporosis and breast cancer. **[Patau Syndrome (Trisomy 13)]**  **Cause:** An extra copy of chromosome 13. **Symptoms:** Severe intellectual disability, congenital heart defects, brain abnormalities, cleft lip/palate, polydactyly (extra fingers or toes), and severe developmental delays. Most affected infants do not survive past the first year of life. **Cause:** An extra copy of chromosome 18.  **Symptoms:** Severe intellectual disability, low birth weight, small head (microcephaly), clenched fists with overlapping fingers, heart defects, and severe developmental delays. Like Patau syndrome, many affected individuals do not survive beyond infancy. **\*\*\*\*\*\*\* Nothing Follows \*\*\*\*\*\*\*** Reference: Freberg, L. (2010). *Discovering Biological Psychology* (2nd ed.). Wadsworth, Cengage Learning. **Prepared by: Dianne E. Agana, MAPsy, RPm**