objects? Is there a simple way to present complex evolutionary processes and the geological timescale without perplexing students
further? Is there a way to express evolution’s key concepts that is
relevant and appealing to students?
It has been suggested that experience with real scientific data
and professional research will help students master computational
reasoning and tree-thinking (Kong et al., 2017). While that is certainly true, we present a complementary perspective here, using
“right-brain” storytelling and images to engage students in evolutionary thinking, phylogenies, and computational biology concepts.
We combine these elements with smaller molecular ideas, leading
to phylogenies and simplified but organism-based tree-thinking.
Tree-thinking, which is a large part of current biological research,
is also (understandably) a difficult concept for students to visualize
and grasp (Meir et al., 2007). To ease into the molecular-evolutionary
diagrams of sequence comparisons and phylogenetic trees, this
article will focus on establishing, through storytelling, a narrative
on the evolution of a particular phylum. Storytelling is a process
of context and connecting the dots; it provides both a wide lens
and ordered, detailed focus (Agosto, 1999). These two perspectives
rework and parallel macroevolutionary and microevolutionary
processes within a narrative form that utilizes real species as protagonists. The organisms of choice for this work are tardigrades,
members of the phylum Tardigrada (known colloquially as “water
bears”). Their story is told in the style of an illustrated children’s
book, similar to Maurice Sendak’s Where the Wild Things Are, Kenneth
Grahame’s The Wind in the Willows, and A. A. Milne’s Winnie the Pooh.
The illustrations translate the abstract concepts of genomes, niches,
microevolution, macroevolution, and phylogenetic trees within a
narrative workbook (see Figure 1 and Table 1; the workbook is
available for download at http://www.timetree.org/public/data/
pdf/JoeTardigrada.pdf). This workbook was produced by the
authors in a computational evolutionary science lab to explore
the potential of storytelling, artistic process, and evolutionary and
In exploring tardigrades’ unique, evolving destinies in geological
time, we create an equality between the reader, the organism, and
the concept of evolutionary process that circumvents inferior/superior
roles. Stories cross cultural boundaries and tell universal tales of creation, metamorphosis, and change (McKeough et al., 2008). Like many
children’s stories, this work relies on anthropomorphic views that are
typically frowned upon in science (Davies, 2010), but it is through
these views that we become conceptually aligned with other forms
of life at an early age. Through the use of narrative, drawing-to-learn
exercises, contemplative coloring activities, and database searches,
students may become reacquainted with, innately drawn to, and connected to other life forms and their evolutionary journeys.
Much has been written about tardigrades. They have – like sloths,
panda bears, and a host of other animals – become embedded in
pop culture, with little regard to their humble beginnings (Kinchin,
2000). Tardigrades are the “organism of the moment,” their Pokémon-like features having seized the attention of non-biologists – a difficult
task indeed for any protostome, but human moments of fame don’t
mean much in geological time, as students may soon find out. Tardigrades were “discovered” under the observant eye of microscope aficionados like the clergyman Joseph Goeze (Wełnicz et al., 2011).
Another clergyman, Lazzaro Spallanzani, experimented with the
little invertebrates to reveal some of their desiccating properties
and their bear-like gait, which earned them the name “slow steppers”
(Withers & Cooper, 2010).
Throughout the 1700s and scattered through time, observations of microscopic organisms becoming reanimated from desiccated states were recorded (Jönsson & Bertolani, 2001). The
ability to desiccate or enter cryptobiotic states was documented
in a number of aquatic organisms, including rotifers, nematodes,
crustaceans, and protozoans. But it was the tardigrades’ “cuteness”
factor that reanimated them in the minds of the general public.
Tardigrades are bilateral micro-metazoans with four pairs of lobo-pod legs that terminate into claws or sucking disks (Nelson,
2002). Their mouthparts are also variable; most siphon sap, but
there is one known parasitic species (Pohlad & Bernard, 1978).
Tardigrades have been trundling through time since their segmentation, more than 550 million years ago in the Cambrian era, and
will likely be moss mingling long after we’re gone. What makes
these organisms so attractive to humans is their staying power
and their extremophile physiology. They occupy a diverse set of
niches, are often only 1 mm long, exhibit a variety of colors as
well as being transparent, and are global travelers, existing even
in Antarctica. While they prefer wet environments, their unique
ability to desiccate and to reproduce parthenogenetically has contributed to their worldwide ubiquity. Tardigrades typically exhibit
low population density but immense diversity, with 1000–12,000 Figure 1. Tardigrada workbook cover.