Navigation
Applying evolutionary theory to current issues like medicine and climate change.
What if the very medicines we use to stay healthy are accidentally creating 'superbugs' that are harder to kill than ever before?
1. A patient has a lung infection with bacteria. 2. are killed by an antibiotic. 3. (100 bacteria) have a mutation that allows them to survive. 4. These 100 bacteria divide every 20 minutes. 5. Within hours, the infection returns, but now of the bacteria are resistant to that specific drug.
Quick Check
In the context of antibiotic resistance, what serves as the 'selection pressure'?
Answer
The antibiotic medication itself is the selection pressure that determines which bacteria live or die.
Quick Check
Why does rapid environmental change lead to extinction rather than evolution?
Answer
Evolution is a slow process relying on random mutations; if the environment changes too fast, species cannot accumulate enough helpful mutations to survive.
While natural selection is driven by survival, artificial selection (or selective breeding) is driven by human preference. For thousands of years, humans have chosen individuals with desirable traits—like the largest corn kernels or the friendliest dogs—to breed. This process mimics natural selection but happens much faster because humans control the mating process. While this has allowed us to create high-yield crops, it often leads to a decrease in genetic diversity. This 'monoculture' makes our food supply vulnerable; if a new disease evolves, it could wipe out an entire crop because every plant is genetically identical.
1. Ancient farmers in Mexico started with Teosinte, a wild grass with tiny, hard kernels. 2. They selected only the plants with the softest and largest seeds. 3. Over years, the genetic makeup shifted entirely. 4. Today, modern corn ( ) cannot even reproduce without human help because its seeds are trapped inside a thick husk, a trait humans selected for ease of harvest.
Which of the following is the primary cause of antibiotic resistance in a bacterial population?
Artificial selection typically increases the genetic diversity of a species.
If the background extinction rate is species per million per year, and the current rate is times higher, what is the current rate?
Review Tomorrow
In 24 hours, try to explain to a friend how a single bottle of hand sanitizer could actually lead to 'stronger' bacteria over time.
Practice Activity
Research one 'heirloom' vegetable and compare its traits to the standard version found in a grocery store. Why did humans select for the grocery store traits?