Biology paper 2

• What is the theory of evolution?

  Gradual change in inherited characteristics
• How does evolution occur?

  Through the process of natural selection
• What does natural selection state about organisms?

  They show a wide range of variation
• What happens to individuals with favorable characteristics?

  They are more likely to survive and breed
• How are characteristics passed on to offspring?

  Through genes
• Why is the theory of evolution by natural selection widely accepted?

  There is substantial supporting data
• What is one piece of evidence for evolution?

  Fossil record
• What do fossils represent?

  Remains of organisms from millions of years ago
• How can fossils be formed?

  From parts that do not decay
• What are hard parts of organisms that can form fossils?

  Bones replaced by minerals
• What can fossils tell scientists?

  How early organisms changed over time
• What are the benefits and problems with the fossil record?

  Benefits:

  • Shows early organisms were soft-bodied
  • Tracks changes in individual species
  • Helps understand life's development

  
  

  Problems:

  • Gaps in the fossil record
  • Some fossils destroyed by geological activity
  • Uncertainty about life's beginnings
• What is extinction?

  No remaining individuals of a species
• What factors can contribute to a species' extinction?

  New predators and diseases
• What catastrophic events can lead to extinction?

  Asteroid impacts and volcanic eruptions
• How do bacteria evolve rapidly?

  They reproduce very quickly
• Why is the development of antibiotic resistance significant?

  It supports the theory of evolution
• Why is the development of new antibiotics slow?

  It is expensive and time-consuming
• How can doctors reduce antibiotic-resistant strains?

  Prescribe antibiotics only for serious infections
• Why should patients complete their antibiotic courses?

  To kill all bacteria and prevent resistance
• How should antibiotics be used in farming?

  Use should be restricted
• What is the term for differences in characteristics among individuals in a population?

  Variation
• What are the three causes of variation in populations?

  Genetic, environmental, and combination causes
• What is a mutation?

  A change in a DNA sequence
• How often do mutations occur?

  Continuously
• What is the effect of most mutations?

  They have no or little effect
• What can happen if a new phenotype is suited to an environmental change?

  It can lead to rapid species change
• What is selective breeding?

  Humans breed plants and animals for traits
• How long have humans been using selective breeding?

  For thousands of years
• What are the disadvantages of selective breeding?

  • Can lead to inbreeding
  • Increases susceptibility to diseases
  • Reduces genetic variation
• What are the steps in the process of selective breeding?

  1. Choose parents with desired traits
  2. Breed them together
  3. Select offspring with desired traits
  4. Repeat over generations
• What characteristics can be targeted in selective breeding?

  Usefulness or appearance
• What is genetic engineering?

  Changing an organism's genome by gene transfer
• What are genetically modified (GM) crops?

  Crops engineered for specific traits
• What are the benefits of genetic engineering?

  • Overcome inherited diseases
  • Higher crop yields
  • Resistance to pests and diseases
• What are the risks associated with genetic engineering?

  • Gene spread to wildlife
  • Negative impacts on ecosystems
  • Ethical concerns about gene manipulation
• How can GM crops be engineered for better adaptation?

  To be resistant to herbicides and pests
• What ethical concerns are raised by genetic engineering?

  Manipulating genes of fetuses for traits
• What are the two main types of reproduction?

  Sexual and asexual reproduction
• What are the characteristics of sexual reproduction?

  • Involves two parents
  • Cell division through meiosis
  • Fusion of male and female gametes
  • Produces genetically different offspring
  • Results in wide variation among offspring