Rosy (synonyms or nicknames: Rosalind, Roseballs, Lady Rose, Roseface, or Rosepot) has some of the sweetest paws you’ll ever squeeze. So when I see her suddenly limping on our walks, it always causes me momentary distress. As we’ve found out, my neighborhood is populated with those little burs that get stuck on your socks and shoes, or in this case, paws. They’re the seeds of Soliva sessilis, a leafy green weed that commonly invades people’s lawns. Though Rosy and I try to avoid them on our walks, she still manages to catch a few each time. To her credit, she’s a champ and patiently holds still as I locate them and pluck them from her feet.
|Fig. A. Thanks Disney.|
We take for granted our two legs and locomotive powers as human animals. They help significantly in our reproductive challenge of genetic diversity. Proven time and time again, diverse genes, when sexually combined, produce more fit offspring. Should genetic diversity be lacking in a reproductive pool, you get inbreeding and decreased fitness (Figure A).
This model is so important that almost any sexually reproductive species you consider has evolved adaptations to accommodate it. Be it the wings of male drone ants that carry them to unrelated queens in different nests or the roaming behaviors observed in male primates (playas, I’m looking at you), Animalia likes lots of genes to choose from when it comes to swapping DNA.
Plants are no different, though they do have the immobility issue to overcome. When it’s likely that a plant’s nearest neighbors are its siblings, it needs a way to get its DNA package over to a plant that is not as closely related. Basically, plants must depend on their environment to do the traveling for them. That environment includes gravity, wind, water, precipitation, bugs, and animals like you and your adorable dog.
For them, it’s a matter of life vs. evolutionary death. They depend on us to get their DNA over to a plant other than their immediate family (who can blame them!?) I prefer they not involve Rosy’s paws in their sexy quests, but I also wish I didn’t have to pluck that weird hair from my forehead every few weeks. Nature deals the cards and we make the best of it.
Actually, the Soliva sessilis burs, though annoyances, are in a way a nice addition to our walks. In a neighborhood where people cut their lawns and trim their bushes so no animals can find refuge, plant non-native flowers, immediately reach for a shovel upon the discovery of a harmless snake and allow their outdoor cats to stalk and kill birds, I secretly root for the little weed. In a humanized, unnatural setting, the little guys are doing what it takes to further the fitness of their species.
You go, little burs.