Little Water Bears
“Strange is this little creature, because the whole organisation of his body is extraordinary and strange and because his external appearance, at the first sight, has the closest similarity to a little bear. This also led me to give him the name little water bear” (cited in Greven 2015).
That’s what German pastor Johann August Ephraim Goeze said in his description of the tardigrade in 1773—what he called “kleinen Wasserbär” (little water bears) because of the way they walk. His description was included as a note in a translation he did of Charles Bonnet’s two-volume work Traite d’Insectologie from French to German. This translation work, done in agreement with Bonnet and at his suggestion, included many footnotes and some new literature. Goeze encouraged others to study their own local ecology as well in this work, saying, “each place has its physical advantages, and in each place, nature has something special in any of its realms. Location, climate, wood, mountains, waters, and the like, require this diversity.” He clearly appreciated God’s creation and the complexity of His design in ecosystems (Greven).
Goeze’s was the first scientific description of these tiny creatures. Within three years after publishing Herrn Karl Bonnets Abhandlungen aus der Insektologie (his translation of Bonnet’s books), three other tardigrade descriptions were published. This was at a time when tardigrades were considered worms and worms were still considered insects. Since then, they have proven to be a source of fascination for scientists and non-scientists alike (Greven).
In 250 years since Goeze’s original description, we’ve learned a lot more about their amazing characteristics and capabilities. Tardigrades are tiny—usually less than 0.5mm long—and mostly live in water films in or on mosses, lichens, and leaf litter. They are distributed globally in both aquatic and terrestrial environments. Tardigrades are multicellular organisms, but because they are so small, adults only have about 1000 cells. They feed on algae, the branching filaments that make up the root-like mycelium of a fungus, or even small metazoans like rotifers and other tardigrades using mouthparts composed of a pair of stylets, a mouth tube, and a muscular pharynx. The stylets are used to poke a hole in the membrane of a food organism and then suck the cellular fluids out.
Experiments have shown that tardigrades can survive extremely dry conditions, temperatures ranging from near absolute zero to above the boiling point of water (-272°C to 151°C), radiation doses that are orders of magnitude higher than humans can withstand, incubation in organic solvents (alcohols), and exposure to the vacuum of space.
These amazing abilities are due to the way God engineered these tiny creatures to operate. As Goeze says, “Creator of elephants and atoms, of whales and the living water dots! I am amazed by the infinite diversity of designs your wisdom used to shape every body of the animal, the bird, the fish, the insect, and the worm in a different way!” (Greven). God has provided genes that enable them to continuously track their environment and respond or adapt to changes and stressful conditions. These include the following:
- Catalases: these are antioxidant enzymes that help to neutralize oxidative stress. Cells enduring stressful conditions often experience such oxidative stress. This is a major source of cell damage.
- DNA repair proteins: when tardigrades are dried out for long periods or exposed to high radiation doses, double-stranded breaks accumulate in their DNA. To recover from this, tardigrades have genes for DNA repair proteins, including one for translesion synthesis, which allows DNA to be replicated even when it is broken—a problem that would normally stall DNA copying.
- Polyamine synthesizing enzymes: Polyamines are small molecules that help protect membranes. One of these polyamines is spermidine, which is produced by an enzyme called spermidine synthase. One tardigrade genome (Hypsibius dujardini ) was found to have 15 genes coding for this enzyme.
- Heat shock proteins: Heat shock proteins are molecular chaperones (a kind of molecule that helps other proteins fold properly). Tardigrades have numerous genes for these proteins, which respond to stresses such as desiccation, radiation exposure, and heat stress (Boothby, et al. 2015).
Some scientists believe tardigrades may have gained many of the genes that help them survive through horizontal gene transfer (HGT) (Boothby, et al.). This is when genes from one organism are passed to another unrelated organism. Prokaryotes (cells without organized nuclei) may do this through a process called conjugation, where two single-celled organisms link together with a tiny tube through which they pass genetic material. HGT has been used by evolutionists to explain how similar gene sequences can exist in very different species. There is no known way that this HGT process could happen in eukaryotes (which contain an organized nucleus in every cell). Nevertheless, Darwinians use this proposed process to explain gene patterns which do not fit the expectations of common descent. When similar genes are observed in very different organisms, that situation is a big problem for evolutionary theory (Creation Science Association of Alberta 2023).
For example, the genome of H. dujardini contains many genes that are very similar to corresponding genes in fungi, plants, Archaea, and viruses. Some scientists think that tardigrades may be unusually susceptible to acquiring foreign DNA from their environment. Boothby, et al. speculate, “When desiccated membranes are rehydrated, they become transiently leaky, making the uptake of large macromolecules possible” though this does not explain how the DNA can be integrated into the tardigrade genome in a functional way (Boothby, et al. 2015), and that is the whole point: the HGT proposal is an attempt to rescue evolution.
Other scientists believe there may be contamination from other microbes that may have been mixed in with the tardigrades during preparation for the experiment. This is because the genome was found to be substantially longer and contained more “foreign” genes than expected. Due to the small size of tardigrades, isolating them and concentrating their DNA for analysis is a time-consuming and complicated process. The majority of HGTs are non-functional. For a foreign gene to become functional in a new organism, it must be integrated into its existing genome (Koutsovoulos, et al. 2016). Instead God probably designed tardigrades with these genes.
As the Almighty said: Let there be; when the earth, this drop in the bucket, ran out of his hand; then he also considered this little worm [the tardigrade], million times smaller than a grain of sand, worthy of being created, and maintained for six thousand years. With what intentions, as my eye has seen it this year perhaps for the first time? Lord! Who has been your advisor? From Him, and through Him, and to Him are all things—to Him be glory—in the suns, in the clouds, in the seas, in the depths, in the visible and invisible world, in the behemoths, and in the little worm, that no eye has seen—to Him be the glory forever—to Him be glory also in my heart.
–Pastor Johann August Ephraim Goeze, 1773 (emphasis his) (Greven )
Boothby, Thomas C. et al. 2015. “Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade.” Edited by W. Ford Doolittle. PNAS 112 (52): 15976-15981. doi:https://doi.org/10.1073/pnas.1510461112.
Creation Science Association of Alberta. 2023. Impact of Worldviews: Horizontal Gene Transfer (HGT). https://headstart.create.ab.ca/term/horizontal-gene-transfer-hgt.
Greven, Hartmut. 2015. “About the little water bear* A commented translation of GOEZE’S note „Ueber den kleinen Wasserbär” from 1773.” Acta Biologica Benrodis 17 (November 2015): 1-27. https://www.researchgate.net/publication/283615362_About_the_little_water_bear_A_commented_translation_of_GOEZE’S_note_Ueber_den_kleinen_Wasserbar_from_1773.
Koutsovoulos, Georgios et al. 2016. “No evidence for extensive horizontal gene transfer in the genome of the tardigrade Hypsibius dujardini.” Edited by W. Ford Dolittle. PNAS 113 (18): 5053-5058. doi:https://doi.org/10.1073/pnas.1600338113.
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