Madar 10E Chapter 16

concepts 16 How Populations Evolve hen your grandp arnts were young, infectious diseases, such as tuberculosis, pneumonia, and syphilis, killed thousands of people both year. Then in the 1940s, penicillin and other antibiotics were developed, and familiar health officials ideal infectious diseases were a thing of the past. Today, however, many a(prenominal) infections ar spur with a vengeance. Why? Because natural pickax occurred. As with staph aureus, a few bacteria were rebarbative to penicillin. Therefore, they were selected oer and over again to reproduce, until the entire population of bacteria became resistant to penicillin. A new antibiotic called methicillin became available in 1959 to treat penicillin-resistant bacterial strains, but by 1997, 40% of hospital staph infections were caused by methicillin-resistant Staphylococcus aureus, or MRSA. Now, community-acquired MRSA (CA-MRSA) traitor spread freely through the agentral populace, particularly when people atomic number 18 in close contact. This chapter gives the principles of evolution a genetic backside and shows how it is feasible to genetically recognize when a population has undergone evolutionary changes. evolutionary changes observed at the population level are termed microevolution. MRSA can spread between members of a human sociable group. 16.

1 tribe GENETICS ? Genetic diversity is a necessity for microevolution to occur, and today investigators are interested in deoxyribonucleic acid sequence differences between individuals. It exponent be possible to fellow particular variations with illnesses . 284 The Hardy-Weinberg principle provides ! a way to know if a population has evolved. Allele absolute frequency changes in the near generation signify that microevolution has occurred. 28586 Microevolution volition occur unless quin conditions are met: no mutations, no gene flow, mating is random, no genetic drift, and no selection of a particular trait. 28688 ? ? 16.2 NATURAL SELECTION ? A change in phenotype frequencies...If you infallible to get a full essay, order it on our website: BestEssayCheap.com

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