Mendel Monsters

Sometimes Trevor comes home from school with creative assignments that sound really fun, like the museum design project for history a few months ago. This week, he came home with science homework about genetics. Working in pairs, the students flipped coins to determine the genotype of two monster offspring. The coin flips represented dominant and recessive traits, including: 

  • Face shape (round is dominant, square is recessive)
  • Neck length (medium is dominant, long is recessive)
  • Body shape (round is dominant, square is recessive)
  • Covering (scales are dominant, hair is recessive)
  • Number of limbs (four is dominant, six is recessive)
  • Digits (fingers are dominant, claws are recessive)
  • Mouth (teeth are dominant, beak is recessive)
  • Tail (no tail is dominant, tail is recessive)
  • Horns (no horns is dominant, horns are recessive)
  • Antenna (no antenna is dominant, antenna are recessive)
  • Eye position (center of face is dominant, top of head is recessive)

Once they'd determined their offsprings' genotypes, they each drew one of the siblings. The drawing showed each monster's phenotype. While Trevor illustrated his monster offspring, Steve and I did our own coin flips to see what we’d each look like as monsters. Here are the results. Steve’s coin flips led to the hairy, square monster on the left, while mine inspired the scaly, round monster on the right.  


As you can see, our phenotypes differ for all but three traits (horns, neck length, and number of limbs). So what would our firstborn look like? In real life, Trevor is a blend of both of us, and the same is true of the monster version of our offspring. Monster Trevor has his dad’s arms, fingers, and mouth, and his mom’s round shape, eye placement, scales, and lack of antenna and tail.

I didn’t get to see Trevor’s partner’s offspring to see any resemblance between the two siblings, but I did grab Trevor’s and scan it before he turned it in. I love it. And I love that his science teacher incorporated art into science for this lesson.

I had great fun illustrating our family as monsters. What an excellent way to introduce kids to inherited traits, dominant and recessive alleles, and genotype vs. phenotype.


  1. What a fun way to learn about this!

  2. What a great idea! I could see flipping coins, drawing monsters, repeat, repeat to fill a rainy day.

    1. Add snacks and that's pretty much my perfect day.

  3. These are sooooooooo fun! I love them!!! And HAPPY BIRTHDAY!!!!!!!!!!!!!!!!!!!

  4. I would roll a 4-sided die to more accurately simulate gene inheritance, but this is cute!


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