Unit 6 Natural Selection Study Guide 

True or False: 

• A phenotype is the genetic code found in an organism’s DNA. __________False it's genotype 

• Genetic variation within a species leads to natural selection occurring. __________ True

• A mutation is a harmful change to an organism’s DNA. ______False; mutations are just changes____ 

• A Goldendoodle was bred for its hypoallergenic qualities. This is an example of natural selection. ______False, it's artificial____ 

•  Fitness refers to an organism’s ability to survive and reproduce offspring. ______True 

• There are 2 types of worms: worms that eat at night (nocturnal) and worms that eat during the day (diurnal).  The birds eat during the day and seem to be eating ONLY the diurnal worms.  The nocturnal worms are in their burrows during this time. Each spring when the worms reproduce, they have about 500 babies but only 100 of these 500 ever become old enough to reproduce.  

• How will this population change over time? ______Nocturnal numbers will go up________ 

•  What worm has better “fitness”? ________nocturnal___ Worse fitness? _____diurnal 

• There are 3 types of polar bears: ones with thick coats, ones with thin coats and ones with medium coats.  It is fall, soon to be winter.  The temperatures are dropping rapidly, and the bears must be kept warm, or they will freeze to death.  Many of the bears have had 2 cubs each but due to the extreme temperatures, many mothers only have one cub left.  

• How will this population change over time? ____more bears will have thick coats___________ 

• What bear has better “fitness”? ____thick coats____ Worse fitness? __thin coats____ 

• Define Natural selection: Process that causes organisms to adapt to their environment due to some with certain traits/phenotypes better surviving to have offspring and pass on their genes

• There are many different dog breeds. Sometimes humans create the type of dog breed that they desire by having a specific breed of dog's mate. Would this be an example of natural or Artificial selection?  Artificial

• What is a mutation? A change in DNA.

• Why are advantageous(good/helpful) traits more likely to be passed onto offspring? Because they allow the organism to survive/reproduce
• What word describes a trait that helps an organism survive in its environment? Adaptation