Human Evolution Study Guide 1 Scientific Method 1 Observation 2 Question 3 Hypothesis 4 Gather Data 5 Analyze Data 6 More Hypothesis Theory in Science Model for understanding natural phenomenon Collection of concepts Conforms to all available data Formal logic Theory in Evolution 150 years of observations Natural Selection Theory o Individuals unique o Traits passed to offspring o Desirable traits more prevalent over time Fitness ability to reproduce as measured by surviving offspring Adaptation result of natural selection neither permanent nor permanent Four Forces of Evolution 1 Mutation a Only source of variation in individuals b Many aren t useful 2 Migration Gene Flow a New traits to different areas 3 Genetic Drift Surviving Population 4 Natural Selection DNA Nucleotide base a Original Population Bottlenecking Event Catastrophic o Sugar Phosphate Base o Adenine Thymine Cytosine Guanine sequence Genes Double helix structure 23 pairs of chromosomes in nucleus humans Locus location of genes on DNA Cell Division Begin with DNA replication Prophase nuclear membrane breaks down chromosomes condense mitotic Interphase DNA replicating in nucleus centrioles separate spindle begins to form Metaphase chromosomes align mitotic spindle develops Anaphase chromosomes separate Telophase new nuclear membrane cells pinch cytokinesis new daughter cells formed mitosis identical meiosis have half of genes Mitosis o Somatic body cells over lifespan starts at fertilization o One parent cell produces two identical daughter cells o Rate of division depends on where cell is located o Diploid cells produced double copies of chromosomes one from each parent 23 pairs Meiosis o Sex cells o Females begins in utero with chromosomes lining up freeze until puberty continues if egg is fertilized stops with menopause o Males begins at puberty with no stopping point o 4 Haploid cells produced one copy of chromosome 23 chromatids singles o 2 phases of division Prophase I crossing over Metaphase I homologous chromosomes side by side genetic recombination chiasma cross formed centromeres do no divide Anaphase I sister chromosomes stay together Metaphase II chromosomes end to end Anaphase II centromeres divide Telophase II 4 haploid daughter cells Gametogenesis Oogenesis egg cells o 3 polar bodies 1 egg o 1 has enough cytoplasm to support life o 2 million eggs Spermatogenesis o 4 sperm cells o 74 days to produce Central Dogma DNA transcription RNA translation Protein carries genetic code from nucleus to ribosome in cytoplasm mRNA messenger smaller than DNA Uracil replaces Thymine Codons group of three bases codes for amino acids o Start codon is AUG methionine o 20 amino acids 64 possible RNA Genetics Genes made up of two alleles one from each parent codes for a trait Law of Segregation pairs of alleles separate during meiosis so that each gamete receives only one copy of a gene Law of Independent Assortment segregation of the alleles of one pair is independent of the segregation of the alleles of another pair Punnett squares Pedigrees o Diagram showing relationships to trace hereditary pattern of a particular trait o Squares male circle female o Autosomal traits equal Dominant RR Rr recessive rr co dominant RS o Sex linked have gender bias Males are hemizygous one X Most likely to be expressed in males Females often carriers
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