UNIT 14BIO

• What is variation in organisms?

  Differences among individuals in a species
• Why do organisms of different species look different?

  Different species have distinct characteristics
• What is an example of variation within a species?

  Different hair colors in a group of people
• What is the term for differences within a species?

  Variation
• What causes genetic variation?

  Differences in genotype among organisms
• How does genotype affect phenotype?

  Genotype determines the characteristics displayed
• How are genes inherited?

  Passed down from parents
• What environmental factor can influence phenotype?

  Conditions in which an organism lives
• How might a plant's growth differ in sunlight versus darkness?

  Sunlight promotes lush growth, darkness stunts it
• What is the relationship between genetic and environmental factors in phenotype?

  Both influence phenotype together
• What is a mutation?

  A rare change in an organism's DNA
• What can a mutation produce?

  A genetic variant of a gene
• How can gene mutations affect proteins?

  They can change the protein's structure
• What is the effect of most genetic variants on phenotype?

  They have little or no effect
• How can a mutation slightly influence characteristics?

  By altering traits like eye color
• What is an example of a mutation with a dramatic effect on phenotype?

  Cystic fibrosis caused by a gene mutation
• How does natural selection relate to phenotype changes?

  New phenotypes can become common through selection
• What is the theory of evolution?

  Species evolved from simple life forms
• Who proposed the theory of evolution by natural selection?

  Charles Darwin
• What is meant by "survival of the fittest"?

  Better adapted organisms survive and reproduce
• What happens to successful organisms in natural selection?

  They reproduce and pass on beneficial genes
• How does natural selection lead to evolution?

  Beneficial traits become more common over time
• What limitation did Darwin's theory have?

  He lacked knowledge of genetics
• How did genetics support Darwin's theory?

  It explained how traits are inherited
• What does the fossil record show?

  Changes in organisms over time
• What is speciation?

  Formation of a new species over time
• What leads to reproductive isolation in speciation?

  Populations change enough to not interbreed
• What does extinction mean?

  No individuals of a species remain
• What are some reasons species become extinct?

  Rapid environmental changes, new predators
• How did humans contribute to the extinction of dodos?

  Hunting and habitat destruction
• What is selective breeding?

  Humans breed plants or animals for traits
• What is the goal of selective breeding?

  To enhance desirable traits in offspring
• What are some examples of traits selected in breeding?

  Meat production, disease resistance, temperament
• What is the process of selective breeding?

  1. Select organisms with desired traits
  2. Breed them together
  3. Select the best offspring
  4. Repeat over generations
• How can selective breeding improve agricultural yields?

  By breeding the best livestock for production
• What is a drawback of selective breeding?

  Reduction in the gene pool
• What is inbreeding?

  Breeding closely related organisms
• What health problems can arise from inbreeding?

  Increased chance of genetic defects
• What is a risk of low genetic variation in a population?

  Higher susceptibility to diseases
• What is genetic engineering?

  Transferring genes between organisms