BIOLOGY AND ENVIRONMENT
BIOLOGY AND ENVIRONMENT #3377 Human Development 101
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This 8 page Class Notes was uploaded by Caroline Smith on Monday September 19, 2016. The Class Notes belongs to #3377 Human Development 101 at University of Alabama - Tuscaloosa taught by Dr. Scofield in Fall 2016. Since its upload, it has received 61 views.
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Date Created: 09/19/16
BIOLOGY AND ENVIRONMENT (CHAPTER 2) Biology o Cells: basic unit of life e.g., skin cells, blood cells, brain cells o Nucleus > Chromosomes > DNA > Genes DNA, Genes o Genes: segment of DNA Codes for specific traits 30,000 genes for traits such as: Intelligence Personality Sexuality Athleticism Polygenic: when multiple genes code for an overall trait [i.e., skin color, height, etc.] o DNA: deoxyribonucleic acid Carries entire genetic code Chromosomes o 23 pairs of chromosomes ½ from mom, ½ from dad o 22 pairs of autosomes Code for most genetic traits o 1 pair of sex chromosomes Code for biological sex XX (girl) or XY (boy) Y carries less genetic material Cell Division o Mitosis: is nuclear division plus cytokinesis, and produces two identical daughter cells during prophase, prometaphase, metaphase, anaphase, and telophase. [Here is a short clip to review the process. It will not be a major part of this course. https://www.youtube.com/watch?v=ofjyw7ARP1c ] Cell division for most cells o Meiosis: is the process whereby chromosomes are copied, paired up and separated to create eggs or sperm. [Here is a short clip to review the process. It will not be a major part of this course. https://www.youtube.com/watch?v=nMEyeKQClqI ] Cell division for sex cells Sperm (male sex cell); Egg (female sex cell) o Crossing Over (genetic recombination) Ensures genetic variability Unique cell with 23 chromosomes Fertilization [Here is a video to show the process of fertilizationhttps://www.youtube.com/watch?v=_5OvgQW6FG4] o Zygote: fertilized egg Sperm (23 chromosomes) Egg (ovum) (23 chromosomes) o Twins Monozygotic (Identical) 1 egg fertilized, divides 3/1000 = twins Dizygotic (Fraternal) 2 eggs released and fertilized These types of twins are becoming more common due to modern fertilization methods. Heredity o Dominant/ recessive heredity [Here is a quick review video for this section. https://www.youtube.com/watch?v=Mehz7tCxjSE] Traits coded by 2 alleles 1 from mom, 1 from dad Dominant (Y); Recessive (y) Homozygous Alike alleles [YY, yy] Heterozygous Unalike alleles [Yy] Carrier: carries, not expresses, recessive allele o Genotype: underlying genetic code [YY, Yy, yy] o Phenotype: expressed trait [In this example, Y stands for the dominant trait of yellow peas. "y" stands for the recessive trait of green peas. So the phenotype would be either yellow or green.] o Xlinked (sexlinked) traits https://www.youtube.com/watch? v=h2xufrHWG3E (Here is a short video with a review)] X chromosome contains more genetic material than Y chromosome Recessive traits on X are passed to male offspring Colorblindness, albinism, hemophilia, baldness More common in males than females (10:1) Chromosomal Abnormalities o Example: Trisomy 21 (Down's Syndrome) Mental Retardation Speech and problems Vision and breathing problems Shortened Lifespan 25 to 49 years old Decreased fertility o Sex chromosomes Klinefelter's (XXY) XYY Syndrome Triple X (XXX) Turner's (XO) [Only one X chromosome] Decreased fertility Misdeveloped sex features Genitals Fat/muscle distribution Body hair Environment o Prenatal (e.g., hormones, drugs, alcohol, disease) o Postnatal Physical (e.g., air, water, nutrition) Social Family (e.g., birth order, parenting, SES) (nonshared environmental influences) Peers (e.g., number, kind) (Harris 'parents don't matter') Community (e.g., size, location, schools) Culture (e.g., norms, values, religion, practices) Reaction Range o How do genes and environment interact? For example, if I have a genetic range that in height in my family from 5' 7" to 6' 2", then my environment can determine where I fall on this range. If I grew up in poverty, then I have the possibility of falling toward the 5' 7" side of the reaction range. If I have better access to nutrition, then I have a higher possibility of falling towards the 6' 2" side of the reaction range. Behavioral Genetics o Genes and environment not independent. Passive effects: parents pass genes to child e.g., webbed feet, etc. Evocative effects: child genes bring out responses from environment e.g., peers call child "frogboy" Active effects: child finds environment that fits genes (i.e., nichepicking) e.g., becomes swimmer Concordance Rates o The chance that 2 individuals have the same trait Identical Twins Criminality: 50% Alcoholism: 55% Sexuality: 50% Depression: 45% Autism: 60% Intelligence: 85% Schizophrenia: 45% Cancer: 16% Diabetes: 50% Fraternal Twins Criminality: 20% Alcoholism: 30% Sexuality: 20% Depression: 25% Autism: 510% Intelligence: 55% Schizophrenia: 15% Cancer: 13% Diabetes: 10%