4. Evolution

• What is natural selection?

  Mechanism by which species change over time
• What does evolution refer to in genetics?

  Change in allele frequency over time
• What is required for natural selection to lead to evolution?

  Genetic variation in the population
• When can an allele become selectively advantageous?

  When the environment changes
• What is the relationship between allele frequency and time in evolution?

  Allele frequency changes over generations
• What is the advantage of heterozygous individuals in sickle cell anaemia?

  They are resistant to malaria
• What are selective pressures?

  Factors changing allele transmission probability
• Why is the S allele still common despite being lethal?

  It provides a survival advantage in malaria areas
• What happens to allele frequencies if sickle cell disease is effectively treated?

  The S allele would become more frequent
• What are the selective pressures affecting allele frequency in sickle cell anaemia?

  • High incidence of malaria favors AS genotype
  • Conflicting pressures in malaria-free areas
  • Carriers may experience symptoms under stress
• What is the trend for allele A and S over three generations?

  A allele decreases, S allele increases
• What is the physiological adaptation of the waxy leaf frog?

  Glands produce waxy lipids to reduce water loss
• What is a behavioral adaptation of the waxy leaf frog?

  Active only at night to hunt insects
• How does the behavioral adaptation help the waxy leaf frog survive?

  It reduces water loss and avoids predators
• What does the term niche refer to in ecology?

  The role and position of a species in its environment
• What are the two variations of peppered moths?

  Pale and black peppered moths
• Which peppered moth variation was more common before the 1800s?

  Pale peppered moths were more common
• Which peppered moth variation became more common after the 1800s?

  Black peppered moths became more common
• How does the story of the peppered moths relate to natural selection?

  Changes in environment favored black moths
• What are the key concepts related to natural selection?

  • Mutation
  • Alleles
  • Variation
  • Selection pressures
  • Survival and competition
  • Advantageous traits
  • Reproduction and gene passing
  • Increased allele frequency
• What is the significance of the industrial revolution for peppered moths?

  It changed the environment favoring darker moths
• How do mutations relate to natural selection?

  Mutations create variation for selection pressures
• How does competition influence natural selection?

  It determines which traits are advantageous
• What is the role of advantageous alleles in natural selection?

  They increase survival and reproduction rates
• What happens to advantageous alleles over generations?

  They increase in frequency in the population
• What is the relationship between phenotypes and natural selection?

  Phenotypes determine survival and reproduction success
• How do selection pressures affect allele transmission?

  They influence which alleles are passed on
• What is the outcome of natural selection on a population?

  Increased frequency of advantageous alleles
• How does natural selection lead to adaptation?

  It favors traits that enhance survival and reproduction
• What is the significance of genetic variation in evolution?

  It provides the raw material for natural selection
• What is the primary focus of the study of evolution?

  Understanding changes in allele frequencies
• What is the role of offspring in natural selection?

  They inherit advantageous traits from parents
• How does the concept of competition relate to natural selection?

  It drives the survival of the fittest individuals
• What is the significance of the term "allele" in genetics?

  It refers to different forms of a gene
• How does mutation contribute to genetic diversity?

  It introduces new alleles into a population
• What is the impact of environmental changes on allele frequency?

  They can make certain alleles more advantageous
• What is the relationship between survival and reproduction in natural selection?

  Survival leads to greater reproductive success
• What is the significance of the term "phenotype"?

  It describes the observable traits of an organism
• How do advantageous traits affect competition among species?

  They enhance survival chances in competitive environments
• What is the role of offspring in the process of natural selection?

  Offspring inherit traits from their parents