Why It Matters: Theory of Evolution

Why explain the theory of evolution, which documents the change in the genetic makeup of a biological population over time?

Have you ever wondered why doctors say you should get a new flu shot every year? It’s just the same old flu virus right? How much could it change from year to year?

Unfortunately, it’s not just the same old flu virus—and it often changes a lot from year to year. When the flu vaccine does its work, killing the current iteration of the flu, it typically does a good job and saves its host from illness. However, as it wipes out the majority of flu viruses, the only ones that are left are those that are resistant to the current virus, which means the overall make up of the population of flu viruses has changed: the population has evolved to become resistant to one anti-viral treatment, so another must be found.

Of course, while the theory of evolution can be applied to viruses, it is more often discussed in the context of living things: bacteria, plants, animals, and even humans. The theory of evolution began as a revolutionary idea, but it remains central to the study of biology. Evolution is the unifying concept in biology. This theory documents the change in the genetic makeup of a biological population over time. Evolution helps us understand the development of antibiotic resistance in bacteria and other parasitic organisms. The following are just a few of the antibiotic resistant “bugs” plaguing humans.

  • Antibiotic-Resistant Mycobacterium tuberculosis (TB)
  • Methicillin-Resistant Staphylococcus aureus (MRSA)
  • Vancomycin-Resistant Enterococci (VRE)
  • Multidrug-Resistant Neisseria gonorrhoeae (Gonorrhea)

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You can also check out the NIH’s website about antimicrobial resistance for more information.

While evolution is easiest to see in bacteria due to their short life cycles, every living population experiences evolution of one kind or another. Let’s see just how the world we live in has guided the evolutionary process.

Learning Outcomes

  • Describe the work of Charles Darwin in the Galapagos Islands, especially his discovery of natural selection in finch populations
  • Describe how the theory of evolution by natural selection is supported by evidence
  • Recognize that mutations are the basis of microevolution; and that adaptations enhance the survival and reproduction of individuals in a population
  • Read and analyze a phylogenetic tree that documents evolutionary relationships


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