A food-safe space is needed; we have used a physics laboratory and
an outdoor classroom, but numerous other campus options are
First, students are divided into two large groups: “Pancake Producers” (with each pancake produced representing an offspring)
and “Pancake Judges” (representing the environment in which offspring are born and, therefore, the selective pressure shaping population traits).
Pancake Producers are divided into groups of two or three
students. Identical pancake batter is provided for all groups, rep-
resenting similar genetic composition, and each group is then
given a unique ingredient (for examples, see Table 2). Clear
instructions are given to each Pancake Producer group and each
Judge (see Tables 3 and 4). Once a single large pancake with
the novel ingredient is made, the pancake is sliced into small
pieces and distributed to the Judges for a “blind” rating on a scale
from 1 (completely inedible) to 10 (delicious); instructors can cre-
ate their own taste scale. A high score represents successful repro-
ductions of the recipe (or the offspring, following the analogy; for
an example, see Table 5, generation 1).
After tabulating the results of generation 1, the previous Judges
become the new Pancake Producers, and the two top-ranking pancake
ingredients are used in the next batch. Half of the newly assigned
Pancake Producers will use winning ingredient 1 from generation 1,
and the other half winning ingredient 2. Each producer group is also
assigned a new ingredient at random (via coin flip or use of a random
number generator; see Table 5, generation 2). Thus, during the
second generation, each pancake will have two ingredients, and the
Table 1. Representation of major components of natural selection, corresponding components in the
laboratory exercise, and potential for misconceptions from the analogy.
Component of Selection &
Evolution Lab Component Potential for Misconceptions
Shared genotypic background Pancake batter The origin of variation appears to be in the
addition of elements (genes) to the organism,
rather than in mutation and genetic
recombination of existing genes.
Trait variation, de novo genetic
Selective environmental pressure Taste preferences, scoring In nature, genotypes and phenotypes that are
more likely to be eaten are less likely to increase
in frequency in the population. The opposite is
true in this activity.
Traits positively affecting survival are
reproduced and thus are more
common in the population
Ingredient perpetuation after
One common misconception is that individuals,
rather than populations, evolve. With only two or
three pancake generations, this misconception
may be reinforced.
Distribution of traits in a population
Table 2. Example ingredients used to illustrate
can change when conditions change
Generation 2 results from
Species and trait extinction/
Low scoring results in not using
the ingredient in subsequent
how alleles can create different phenotypes.
“Gene”“Allele 1” “Allele 2”
Spice Cumin Paprika
Dairy Cheddar cheese Blue cheese
Vegetable Kale Pickles
Candy Chocolate chip Caramel
Condiment Hot sauce Mustard
Candy bar Reese’s Cup Milky Way
Meat Bacon bits Vienna sausage
Table 3. Instructions for “Pancake Producers” ( i.e.,
Step 1 Prepare your batter with the assigned ingredient.
Step 2 Cook a single, large pancake (your offspring) in the
provided pan on the burner with a setting of
Step 3 Cut your pancake into enough pieces for each
Judge and distribute.
Step 4 Clean your pan and cooking area.
Step 5 You will now become a “Pancake Judge” for the
next generation of pancakes.