What must be necessary for it to happen

What must be necessary for it to happen? Differential reproduction What has happened? Source: http: //evolution. berkeley. edu/

• You are given an antibiotic after a long period of fighting a respiratory infection. The instructions say to take the medication for 10 days but the symptoms clear up after 6 days. Since you don’t like taking medicine unnecessarily and it seems to have some unpleasant gastrointestinal sideeffects you stop taking it. • Is this a good idea?

Examples of Natural Selection and Drug Resistance • Video clips (from PBSLearning. Media): – Frontline: The Decreasing Effectiveness of Antibiotics (2: 27) – Nova science. Now: Killer Microbe (5: 13) – Evolution: Evolving Ideas: Why does Evolution Matter Now?

What do these terms have in common? How do they differ? • • Biocide Antibiotic Antibacterial Disinfectant Antimicrobial Antiseptic Antifungal Antiviral What root words do you recognize?

When and why do we use them? • Drugs to fight infections in humans (antibiotics) • Feed to livestock to prevent disease and to help them grow faster (antibiotics) – Union of Concerned Scientists estimates 70% of antibiotics in US are feed to animals) • In consumer products, including personal care products, to prevent or slow the growth of bacteria (We will call these antibacterials)

• At least 2 million Americans fall ill from antibiotic resistant bacteria every year and at least 23, 000 die from those infections. – Center for Disease Control (CDC) Threat Report 2013

• Antibiotic resistance is never going to go away. No matter how many drugs we throw at it, no matter how much money and resources are sacrificed to wage a war on resistance, it will always prevail. • - American Academy of Microbiology (2008)

What types of consumer products containing antibacterials do you use?

• Triclosan (TCS) and Triclocarban (TCC) were present in 75% of liquid soaps and 29% of bar soaps in 1999/2000 and their use has grown. • They are among the top 10 water contaminants in the US.

(Image source: Halden RU. 2014. On the Need and Speed of Regulating Triclosan and Triclocarban in the United States. Environ Sci Technol 48: 3603 -3611. )

Lab: • Do water samples collected from a local water shed contain microorganisms resistant to antibiotics and antibacterial products? • Can the presence/extent of antibiotic resistance be related to geographic location esp. human impact? • How can we find out?

Lab Procedure 1. Label Petri dish 4. Add soap or triclosan to blank disk 2. Add water sample (and spread on plate) 5. A finished plate 3. Add antibiotic disks Incubate plates upside down

http: //www. lab-initio. com/screen_res/nz 302. jpg

Natural Selection and Climate Change What does “success” mean in terms of evolution? What do these species have in common? Canadian squirrels with genes for breeding earlier In the spring are more successful than those with genes for breeding later. Wyeomayi smithii, a mosquito that breeds in NA Pitcher plants , Mosquitos with genes that cause them to go dormant later in the fall are more successful than those that go dormant earlier The blackcap is a British bird that used to migrate in the winter. Now some populations winter in the UK. These populations are genetically distinct. They benefit from having earlier access to breeding sites and are more successful Source: UCB Museum of Paleontology

Natural Selection in Response to Pollution Some New Bedford killifish and Atlantic tomcods have a changes in DNA that gives them resistance to PCBs (polychlorinated biphenyls). Industrial melanism with the peppered moth – Darker forms were favored during the Industrial Revolution until coal burning was regulated. (Image: BBC GCSE Bitesize)

Where do triclosan and tricarban go after we finish with them? • Video clips from PBSLearning. Media: – Outdoors Maryland: What’s in the Water (5: 30) – Frontline: Poisoned Waters: New Contaminants in the Water Supply (3: 24) – Frontline: Poisoned Waters: What’s in Your Drinking Water (5: 54) (endocrine disruptors)

Are antibacterial soaps effective? • The FDA has not found any evidence that using triclosan is any more effective than washing with soap and water. • The FDA proposed a rule in December 2013 that manufacturers needed to show that use of triclosan was more effective than the use of soap and water.

What Should We Do about the Problems Posed by Triclosan and Tricarban? • brainstorm

Many Environmental Engineers work to Improve Water Supply and Quality Some solutions come from mimicking and enhancing natural systems. • Using wetlands to further clean effluent from WWTP • Using natural materials (geomedia) iron oxides and biochars to remove contaminants from runoff as water percolates • Promoting the growth of bivalves to remove trace organic compounds and pathogens. Source: Re. NUWit