Evolution: natural selection’

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

  You should be able to describe what is meant by evolution.
• What is the second concept you should be able to explain by the end of the video?

  You should be able to explain how evolution takes place through natural selection.
• What does the earth contain in terms of living organisms?

  The earth is teeming with living organisms, including large animals like mammals and fish, and smaller animals like insects.
• How many different species of animals and plants are estimated to exist on earth?

  There are nearly 9 million different species of animals and plants on earth.
• What percentage of species that have ever lived on earth are currently alive?

  It is thought that only one percent of the total species that have ever lived on earth are currently alive.
• When do scientists believe life first developed on earth?

  Scientists believe life first developed on earth more than 3 billion years ago.
• What were the first life-forms on earth described as?

  The first life-forms were very simple, such as single cells.
• What do scientists call the process by which all species of living things have evolved from simple life forms?

  Scientists call this process evolution by natural selection.
• What is necessary to describe the process of evolution by natural selection?


  You need to be able to describe the process of natural selection.
• What is a good example of genetic variation within a population?

  A good example is with rabbits, where each rabbit has a slightly different combination of alleles inherited from its parents.
• What can some rabbits inherit that gives them advantages in survival?

  Some rabbits can inherit alleles for thicker fur, better eyesight, or better hearing.
• What happens to rabbits with alleles for thicker fur when the environment gets colder?

  Rabbits with alleles for thicker fur are more likely to survive the colder temperatures.
• What is the result of rabbits with thicker fur surviving and reproducing?

  Their offspring could inherit the alleles for thicker fur and are also more likely to survive and reproduce.
• What do scientists call the process where certain traits become more common in a population over generations?

  Scientists call this process natural selection.
• How does the introduction of a predator affect the rabbit population?

  Rabbits with alleles for better eyesight or better hearing have an advantage in detecting the predator.
• What happens to rabbits with better eyesight or hearing in the presence of a predator?

  These rabbits are more likely to survive and reproduce.
• What occurs to the beneficial alleles over many generations in the rabbit population?

  The beneficial alleles for better eyesight or hearing will become widespread in the rabbit population.
• What is the definition of evolution?

  Evolution is the change in the inherited characteristics of a population over time through a process of natural selection.
• What can happen when two populations of one species become so different in phenotype?

  They can no longer interbreed to produce fertile offspring and become two separate species.
• What is an example of two different species of rabbits mentioned in the video?

  The normal-sized rabbit and the pygmy rabbit.
• Why are pygmy rabbits considered a different species from normal-sized rabbits?

  Pygmy rabbits are so small that they cannot breed successfully with normal-sized rabbits.
• What will be covered in more detail in a later video for those who don't study biology?

  Speciation will be covered in more detail in a later video.
• Where can you find plenty of questions on evolution by natural selection?

  You can find plenty of questions on evolution by natural selection in the vision world book.