CHAPTER 5 - CHAPTER 5 ECOSYSTEMS AND EVOLUTIONARY CHANGE I....

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CHAPTER 5 ECOSYSTEMS AND EVOLUTIONARY CHANGE I. What is Evolution? Evolution is the change in the gene pool over time. A. What is the Gene Pool. 1. It is all the various genes in a species B. What is a gene? 1. A gene is the sequence of bases on DNA that code for a protein 2. What is DNA? a. Deoxyribonucleic acid consists of: · deoxyribose (a sugar with one oxygen) · phosphate · base - purines: adenine and guanine - pyrimidines: thymine and cytosine b. The three molecules that constitute DNA are called nucleotides and because nucleotides repeat themselves throughout the DNA molecule, DNA is called a polymer. c. The DNA molecule consists of two strands of the repeating deoxyribose, phosphate, and base sequence. The bases in one strand match with predicatable bases on the opposite strand of the repeating nucleotides (adenine, thymine and guanine, cytosine). d. Two double-stranded DNA molecules combine to form a chromosome.
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C. What is a Chromosome? 1. Chromosomes comprise two DNA molecules (two double-stranded helixes). 2. Each chromosome contains many genes. 3. Different species have different number of chromosomes. The human female has 23 homologous pairs of chromosomes, whereas the human male has 22 homologous chromosomes and 1 nonhomologous chromosome. D. What is a Gene? 1. A gene is a sequence of bases on DNA that code for a specific protein. Genes specify proteins and proteins determine everything else. 2. Genes determine a. Physical traits, e.g., height, body build, and hair color b. Metabolic traits, e.g., allergies and ability to process alcohol c. Growth and Development, e.g., onset of puberty and menopause E. If genes are found on the DNA, and humans all have the same kind of genes, then why don't we all look identical? 1. Alleles:
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CHAPTER 5 - CHAPTER 5 ECOSYSTEMS AND EVOLUTIONARY CHANGE I....

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