#AP Biology: Evolution - The Night Before 🌠

Hey! Let's get you feeling confident about evolution. This is a big topic, but we'll break it down so it's super clear. Remember, you've got this! 💪

Evolution is a core concept in AP Biology, appearing in multiple units. Understanding natural selection and its consequences is crucial.

#Genomic Changes and Evidence for Evolution

Evolution isn't just a theory; it's backed by tons of evidence! One of the biggest clues is that every species shows genomic changes over time. This points to a shared common ancestor.

#Natural Selection in Action

• Antibiotic Resistance: Bacteria adapting to resist antibiotics is a prime example of natural selection. 🦠

  • Random mutations can make some bacteria resistant.
  • These resistant bacteria survive and reproduce, passing on their resistance.
  • This makes the antibiotic less effective.
  • This process is also seen with pesticides, herbicides, and even chemotherapy drugs.
  • Pathogens evolve, leading to new diseases or the re-emergence of old ones.

  

#Populations and Evolution

Evolution happens at the population level, not within individuals.

#How Populations Evolve

Here are some key ways populations change over time:

1. Genomic Changes Over Time:

   • Mutations, recombination, and genetic drift alter the genetic makeup of a population.
   • This can lead to new traits or the loss of old ones.
   • Ultimately, this can result in new species.

   

2. Continuous Change in the Fossil Record:

   • Fossils show how life has changed over millions of years.
   • They reveal that many species that once existed are now extinct.
   • The fossil record provides a timeline of evolutionary changes.

   

3. Evolution of Resistance:

   • Exposure to antibiotics, pesticides, etc., can lead to resistance.
   • Individuals with resistance survive and pass on their traits.
   • This is a major concern in medicine and agriculture.

   

4. Pathogen Evolution:

   • Pathogens like viruses and bacteria evolve rapidly.
   • This can lead to new diseases or the re-emergence of old ones.
   • The COVID-19 pandemic is a perfect example of this.

#Final Exam Focus

Okay, here's what to really focus on for the exam:

• Natural Selection: Understand how it works and its effects on populations.
• Evidence for Evolution: Genomic changes, fossil records, and resistance are key.
• Antibiotic Resistance: A classic example of natural selection and evolution in real-time.
• Pathogen Evolution: Be aware of how quickly pathogens can evolve and cause new diseases.

#Last-Minute Tips

• Time Management: Don't spend too long on one question. Move on and come back if needed.
• Read Carefully: Pay close attention to what the question is asking.
• FRQs: Always provide a clear, concise answer that addresses all parts of the question.
• Multiple Choice: Process of elimination is your friend.

#Practice Questions

Practice Question

#Multiple Choice Questions:

1. A population of bacteria is treated with an antibiotic. Initially, most of the bacteria die, but a few survive. Which statement best explains why some bacteria survived? a) The antibiotic caused mutations in the bacteria, making them resistant. b) The bacteria that survived were already resistant due to pre-existing genetic variation. c) The bacteria learned to adapt to the antibiotic. d) The bacteria that survived were stronger than the others.

2. The fossil record provides evidence for which of the following? a) The spontaneous generation of life. b) The constant rate of evolution across all species. c) The change in the forms and structures of living things over time. d) The perfection of species through natural selection.

#Free Response Question:

A population of insects is exposed to a new pesticide. Initially, the pesticide kills most of the insects, but over time, the population rebounds and becomes resistant to the pesticide.

a) Explain how natural selection leads to the evolution of pesticide resistance in this insect population. (4 points) b) Describe two other ways that populations can evolve over time besides natural selection. (4 points) c) Discuss the implications of pesticide resistance for agriculture and human health. (2 points)

#Scoring Breakdown:

a) (4 points) - 1 point: Mention of genetic variation within the insect population - 1 point: Explanation that some insects have a genetic mutation that makes them resistant to the pesticide - 1 point: Explanation that these resistant insects survive and reproduce - 1 point: Explanation that over time, the population shifts to become predominantly resistant

b) (4 points) - 2 points: Description of genomic changes: mutations, recombination, or genetic drift - 2 points: Description of pathogen evolution or changes in the fossil record (1 point for each correct description)

c) (2 points) - 1 point: Mention of reduced effectiveness of pesticides, leading to crop damage - 1 point: Mention of potential health risks from increased pesticide use or resistant pests

You've got this! Go rock that exam! 🎉