Chapter 2 notes - 9/10/2009 GENETIC BASES OF DEVELOPMENT...

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9/10/2009 1 GENETIC BASES OF DEVELOPMENT Evolution and Heredity We inherit genes from our parents Evolution: nature of genes has evolved Genes determine behaviors and physical traits Traits that are adaptive Aid in survival and reproduction Evolution Basic concept: Individuals that possess traits that aid in survival are more likely to live to pass on those traits to their offspring Individuals w/out those traits are less likely to reproduce The population gradually changes so that nearly all individuals possess these adaptive traits Natural Selection
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9/10/2009 2 Outline of evolution/speciation Evolve through single celled organism, through primitive forms, underwater vertebrates, forms with limbs, forms with developed neural systems Phylogeny: the evolutionary history of a given organism (or species the organism belongs to) What does this have to do with individual development? Ontogeny: the developmental history of an individual Human Embryo: single cell, then simple multi-cellular form, then simple form with gills, then development of skeletal structure, and musculoskeletal system, and nervous system/brain structures A classic philosophical question among developmental theorists. .. Does Ontogeny recapitulate phylogeny? Does the development of an individual organism follow the same path/stages as the development of the species? Why might it do so? Do genes have anything to do with it?
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9/10/2009 3 Heredity and Chromosomes Each egg and each sperm contain 23 chromosomes Fertilization: sperm and egg combine Embryo has 46 chromosomes Defines the child’s heredity Including sex and other physical traits
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9/10/2009 4 Chromosomal abnormalities Down Syndrome Trisomy 21: An extra copy of chromosome 21 (have 3 instead of 2) Facial deformities, delayed motor and mental abilities Increased risk with age of mother Klinefelter syndrome Males have extra x chromosome (XXY instead of XY) Undeveloped testes and some feminine features (including breasts) Fragile X syndrome Damaged X chromosome Delayed or reduced mental abilities Chromosomal abnormalities Turner syndrome Females missing one of the X chromosomes Some physical deformity, infertility and some mental retardation XYY syndrome Males with an extra Y chromosome Slight increases in physical growth rate Slight delays in language development Chromosomes Each chromosome is a DNA molecule Each chromosome consists of 30,000-50,000 genes Genes regulate development of physical and psychological traits and abilities How?
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9/10/2009 5 Effects of genes Individuals not the sole product of their genes Environmental factors influence development as well Genotype: a person’s genetic makeup Phenotype: a person’s actual features The genotype and phenotype are not identical Development Genes determine genotype Genes + Environment determine phenotype
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This note was uploaded on 05/16/2011 for the course DEP 2004 taught by Professor Staff during the Spring '08 term at University of Central Florida.

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Chapter 2 notes - 9/10/2009 GENETIC BASES OF DEVELOPMENT...

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