Read through the cards below. They tell the story of how MRSA, a methicillin-resistant strain of Staphylococcus aureus, developed. The story won't make sense, though, until you arrange the cards in the appropriate sequence from bottom to top on the timeline.
Is Staphylococcus aureus diverging into a new species? How can you tell when evolution is taking place? What evidence should you look for? Click the image below for additional information about antibiotic-resistant bacteria and what you can do to help out. The link opens in a new window. When you have finished reading both pages, simply close the window to return to the resource.
This image is in the public domain courtesy of the CDC and Matthew J. Arduino, DRPH. Photo credit: Janice Haney Carr. Image # 11157 downloaded from //phil.cdc.gov/phil/details.asp.
Other populations of organisms, like bacteria, are also affected by environmental pressures. The organisms that survive or thrive under those pressures reproduce to pass their successful traits to the next generation. Scientists study fossils, compare genomes, and analyze relationship patterns of organisms to their environment and to one another to see if there is additional evidence for evolution. In the next section, you get to be a paleobotonist examining fossils for evidence of environmental pressures on plants.
Weblink source http://evolution.berkeley.edu/evosite/relevance/IA1antibiotics.shtml