Lately I’ve been noticing pollinators on wildflowers as I’ve passed by. The butterfly on the arnica, the beetle on the rose, and the flies on the parsley. There is a curious connection between flowers, insects, and the evolution of plants.
Some of Earth’s 4.5 billion years of history is preserved in the rock record, with some life forms having been preserved as fossils. Fossils and sedimentary rock are laid down in layers with the newest layers deposited on the top, and the oldest layers buried at the bottom. This gives us a pretty good idea of older vs. newer.
The rock record tells us that among the first green plants on land were primitive mosses and liverworts, later followed by horsetails and ferns. All of these plants reproduced through windborne spores. The horsetails and ferns were the first plants to develop into “vascular plants”. Evaporation through the leaf surfaces of these plants produced a sucking action through the roots that in turn brought in fresh water and nutrients to nourish the plant.
The horsetails and ferns thrived for hundreds of millions of years in an earth-climate that was much warmer than today, and with ample water because of melted polar ice caps. Horsetails grew to the size of tall trees, and ferns and mosses flourished. Our present day coal beds are the result of the decayed remnants of this “carboniferous period”.
The next major types of plants to evolve were the gymnosperms; better known as the pines, spruces and firs. These successful plants not only were vascular plants, but were the first plants to reproduce by the means of the all-powerful seed. The male and female components of the seed were often from two different individuals of the same species. The strongest traits of the male and female components of the seed were passed onto the offspring. This seed had an advantage over the spores in that upon hitting the ground, it was encapsulated with a little power-pack which provided nutrients while the plant established itself among competitors.
In the case of the pines, spruces, and firs, the wind did the pollinating as locally evidenced by the early summer coating of pollen on our cars, decks, and outdoor furniture. Thank goodness for the arrival of insects otherwise we may have had to spend the entire summer coated in pollen.
As the history in the fossil record next indicates, the newly evolved flowering-plants arrived on the scene. Interestingly, preserved simultaneously within the record were the fossilized remains of insects. The evidence strongly suggests that diverse flowering plants developed showy, colorful parts and scents to attract pollen-carrying insects. The insects benefited the flowers by spreading the male component of the seed to precisely the right places, while the flower benefited the insects by providing steady food. This win-win could be considered an example of co-evolution, and how life as different as plants and insects develop simultaneously seemingly out of thin air is a great mystery.
It is a great summer for wildflowers and it is perfect timing to get in a hike, bike, or a drive up into the high country. And as the hummingbird zips around overhead, as the butterflies flutter in spiraling circles, and as that emerald green iridescence catches your eye from the back of the tiny beetle camped out in the rose blossom you were about to smell, remember, the world never stops changing.