Question

5-11 Explain the phrase 'bacterial resistance'. Does this phenomenon qualify as evolution? Why or why not? Name and describe 2 examples of human infections that are caused by bacteria that exhibit resistance to some of our commonly used antibiotics. Example 1: Example 2: 5-12 Anthrax, a notoriously dangerous bacterium, is often common in soil. So why is it so dangerous? 5-13 When scientists contemplate possible life on Mars, they focus on the possibility of bacterial-like cells, not cells more complex. Why? 5-14 Bacteria make up a significant portion of the weight of your body. Where are they hiding? 5-15 In recent years, attitudes have changed regarding the inclusion of antibiotics in various household products. Identify one household product where this has occurred.

Answer 1

5-11

Bacterial resistance is the ability of the bacteria to resist the effects of medication which was once effective against it. Yes, this phenomenon qualifies as evolution. Antibiotic resistance is a consequence of evolution via natural selection. The action of antibiotics is an environmental pressure. The bacteria which are able to undergo mutation so as to combat that pressure will evolve.

Example1: Methicillin-resistant Staphylococcus aureus resistant to the action of methicillin

Example2: Multidrug resistant Mycobacterium tuberculosis resistant to TB drugs isoniazid and rifampicin

5-12

Anthrax forms spores that can lie dormant in extremely harsh conditions that reactivate when inhaled, ingested or come in contact with a skin lesion.

5-13

This is because the bacteria or bacteria-like cells have the ability to sustain the harsh conditions on Mars. In fact, bacteria have evolved enormously from the time of the birth of Earth and it is still continuing to evolve.

5-14

Our body is inhabited by millions of tiny living organisms which altogether constitute the human microbiota. They are found in the skin, nose, mouth and especially in the gut.