variation and evolution

• What should you be able to describe by the end of the video?

  What is meant by evolution
• How does evolution take place according to the video?

  Through natural selection
• How many different species of animals and plants are there on Earth?

  Nearly 9 million
• What percentage of species that have ever lived on Earth are currently alive?

  Only one percent
• How long ago did life first develop on Earth?

  More than 3 billion years ago
• What were the first life-forms on Earth described in the video?

  Very simple single cells
• What is the process called where all species of living things have evolved from simple life forms?

  Evolution by natural selection
• What is an example of genetic variation mentioned in the video?

  Different combinations of alleles in rabbits
• What advantage do rabbits with thicker fur have in a colder environment?

  They are more likely to survive
• What happens to the alleles for thicker fur over many generations?

  They become more common in the population
• How does the introduction of a predator affect rabbit populations?

  Rabbits with better eyesight or hearing survive
• What is the definition of evolution provided in the video?

  Change in inherited characteristics over time
• What is meant by variation in biology?

  Differences in characteristics of individuals
• What occurs when two populations of one species can no longer interbreed?

  They become two separate species
• What are the three main causes of variation in a population?

  Genetic causes, environmental causes, and combinations
• What is an example of genetic variation in humans?

  Hair color and eye color
• What is an example of two different species mentioned in the video?

  Normal-sized rabbits and pygmy rabbits
• How does the environment cause variation in flowers?

  The color depends on the pH of the soil
• What is an example of variation caused by a combination of genes and the environment?

  Height in humans
• Why can't pygmy rabbits breed successfully with normal-sized rabbits?

  They are too different in phenotype
• What will be covered in more detail in a later video?

  Speciation
• Where can you find questions on evolution by natural selection?

  In the vision world book
• What is the role of alleles in the survival of rabbits?

  They determine traits that affect survival
• How does natural selection lead to evolution in a population?

  Survival of individuals with advantageous traits
• How do alleles influence height in humans?

  They determine the likelihood of growing taller
• What is the effect of most mutations on phenotype?

  Most have no effect at all
• What are mutations in the context of genetic variation?

  Random changes to DNA
• How can some mutations influence phenotype?

  By affecting traits like tallness
• What is the significance of environmental changes in natural selection?

  They create new survival challenges for species
• What is a key idea about mutations and phenotypes?

  Very rarely can lead to a new phenotype
• How can a beneficial mutation affect a species?

  It can lead to rapid change in the species
• What happened to the rabbit population in the UK in the 1950s?

  A mutation made rabbits resistant to a virus
• What is the significance of the mutation in the rabbit population?

  It gave rabbits a new beneficial phenotype
• Where can students find questions on variation for revision?

  In the revision workbook
• What is genetic engineering?

  Modification of an organism's genome
• How is genetic engineering used in medicine?

  To produce human insulin for diabetes
• How is genetic engineering used in agriculture?

  To create genetically modified (GM) crops
• What do genetically modified (GM) crops generally produce?

  A greater yield than normal crops
• What is a good example of genetic engineering in medicine?

  Production of human insulin
• Why do people with type 1 diabetes need insulin?

  They cannot produce their own insulin