Revision

• How does gene flow occur in a population?

  Through migration of alleles into or out of a population
• What are the terms used for alleles coming into and leaving a population?


  Immigration for alleles coming in and emigration for alleles going out
• What are the two types of genetic drift discussed?

  • Bottleneck effect
  • Founder effect
• How does genetic drift differ from natural selection?

  Genetic drift does not favor one allele over another
• Why does a smaller population experience a greater impact from genetic drift?

  Because there is less genetic variability to buffer against changes
• What is the bottleneck effect?

  It occurs when a population's size is drastically reduced, affecting allele frequencies
• What can cause a bottleneck effect?

  A natural disaster, such as a bushfire or flood
• What is the founder effect?

  It occurs when a new colony is established by a small group from a larger population
• How does the founder effect impact genetic variation?

  It typically results in reduced genetic variation in the new population
• How do bottleneck and founder effects affect genetic diversity?

  • Both decrease genetic diversity
  • Bottleneck effect reduces diversity through random removal of alleles
  • Founder effect reduces diversity due to a non-random sample of the original population
• How does gene flow affect genetic diversity?

  It can introduce or remove alleles, increasing or decreasing variation
• What is a gene mutation?

  A change in the genetic material making up a gene
• What are the three categories of mutations?

  • Point mutations
  • Frameshift mutations
  • Block mutations
• What is a point mutation?


  A mutation that affects a single base in the DNA sequence
• What are the three impacts of point mutations?

  Silent, nonsense, and missense mutations
• What is a silent mutation?


  A mutation that does not change the amino acid encoded
• What is a nonsense mutation?

  A mutation that results in a stop codon instead of an amino acid
• What is a missense mutation?

  A mutation that results in a different amino acid being formed
• What is a frameshift mutation?

  A mutation that alters the reading frame of the genetic code
• What is a block mutation?

  A mutation that affects segments of whole chromosomes
• What is selective breeding?

  • A form of artificial selection
  • Involves human intervention to manipulate gene pools
  • Examples include dog breeding and dairy production
• What is the impact of selective breeding on survival and reproduction?

  It can risk survival and reproduction by selecting for traits that may not be advantageous
• What is bacterial resistance?

  • A consequence of genetic changes in bacteria
  • Involves variation in bacterial populations
  • Selection pressure from antibiotics leads to resistant strains
• How does antibiotic resistance develop in bacteria?

  Through variation and selection pressure from exposure to antibiotics
• What happens to non-resistant bacteria when exposed to antibiotics?

  They are killed off, allowing resistant bacteria to survive and reproduce
• What is binary fission in bacteria?

  A method of asexual reproduction where bacteria replicate
• What is the result of increased allele frequency in antibiotic-resistant bacteria?

  It necessitates finding new antibiotics and treatments
• What is a fossil?

  A fossil is a remain or impression that has been preserved.
• How are fossils typically formed?

  Fossils are usually formed underwater when they are quickly buried under sediment.
• What are some examples of fossils?

  Bones, teeth, shells, eggs, and footprints
• What is a mineralized fossil?

  A mineralized fossil is one that has turned into rock.
• What is a mold in terms of fossils?

  A mold is an impression left by a decomposed bone.
• What is a cast in terms of fossils?

  A cast is formed when volcanic rock fills up a mold.
• What conditions are necessary for fossilization to occur?

  Rapid burial, accumulation of sediment, and an alkaline or oxygen-depleted environment.
• Why is rapid burial important for fossilization?

  It prevents decomposition and allows sediment to accumulate quickly.
• What is relative age in terms of fossils?

  Relative age is determined by comparing the unknown fossil to known fossils based on sediment layers.
• What is an index fossil?

  An index fossil is a known fossil used to compare the age of an unknown fossil.
• What is absolute dating?

  Absolute dating uses radioactive isotopes to determine the exact age of a fossil.
• What is the significance of half-life in radiometric dating?

  Half-life helps determine the age of a fossil by measuring the decay of radioactive isotopes.
• What is speciation?

  Speciation is the process in which populations diverge to become distinct species.