variation and evolution

• What is variation?

  Differences in characteristics between individuals
• Name two types of variation.

  Genetic variation and environmental variation
• What causes genetic variation?

  Inherited genes, mutations, and sexual reproduction
• What causes environmental variation?

  Differences in the environment, such as diet
• Give an example of a characteristic determined solely by genetic variation.

  Eye color, blood group, or ability to roll the tongue
• What is a mutation?

  A change in the DNA sequence of a gene
• Are all mutations harmful?

  No, most are neutral, some are beneficial
• How can a mutation benefit an organism?

  It may provide an advantage, such as resistance
• How can a mutation cause disease?

  It can disrupt normal protein function
• How does sexual reproduction lead to genetic variation?

  Offspring inherit a mix of alleles from both parents
• What is evolution?

  The gradual change in characteristics of a species
• What is the mechanism behind evolution?

  Natural selection
• Who proposed the theory of evolution by natural selection?

  Charles Darwin
• What book did Darwin publish on evolution?

  "On the Origin of Species" (1859)
• What is an adaptation?

  A characteristic that increases survival and reproduction
• What are the key steps in natural selection?

  • Variation exists in a population
  • Competition for resources occurs
  • Better-adapted individuals survive and reproduce
  • Beneficial traits are passed on to the next generation
• Why is genetic variation important in natural selection?

  It provides a pool of traits for survival
• What is survival of the fittest?

  The best-adapted organisms are more likely to survive
• What role does overproduction of offspring play in natural selection?

  It ensures competition, so only the fittest survive
• Give an example of natural selection in action.

  The development of antibiotic resistance in bacteria
• What is speciation?

  The formation of a new species
• What causes speciation?

  Isolation and genetic variation leading to reproductive barriers
• What is geographical isolation?

  When populations are separated by physical barriers
• How does geographical isolation lead to speciation?

  Isolated groups evolve separately due to different pressures
• Give an example of speciation caused by geographical isolation.

  The finches on the Galápagos Islands
• Name three types of evidence for evolution.

  Fossil records, comparative anatomy, and genetic analysis
• What are fossils?

  Preserved remains or traces of ancient organisms
• What does the fossil record show?

  It shows how organisms have changed over millions of years
• What is comparative anatomy?

  Studying similarities in structures of different species
• How does genetic evidence support evolution?

  Similar DNA sequences show relationships between species
• What is selective breeding?

  Choosing individuals with desired traits to breed
• Name two desirable traits in selective breeding of animals.

  Disease resistance and increased milk yield
• Name a downside of selective breeding.

  Reduced genetic diversity, leading to inbreeding
• What is a genetically uniform population?

  A population with little genetic variation
• Give an example of selective breeding in plants.

  Developing drought-resistant crop varieties
• What is genetic engineering?

  Modifying the DNA of an organism
• Name an application of genetic engineering.

  Producing insulin from genetically engineered bacteria
• What are genetically modified (GM) crops?

  Crops with altered genes to improve yield
• What are the concerns about GM organisms?

  Ethical issues, potential environmental harm
• What is the role of enzymes in genetic engineering?

  They cut DNA and insert new genes