Flower Power

What would a world without flowers be like?

The dinosaurs knew the answer to that question, as they lived in an age before the evolution of angiosperms, the flowering plants.

Angiosperms are the most diverse group of land plants on Earth today, and include not only all the plants whose blooms we appreciate, like roses, but all our deciduous trees and grasses, and grains--corn, rice, and wheat.

Paleontologists have modeled the flower-less Earth scenario, and found that an Earth without flowers would not only be less colorful, but it would be hotter and drier, as the leaves from angiosperms add a significant amount of water vapor to the atmosphere through the process of transpiration.

Moisture impacts biodiversity as well, and a flower-less Earth would have fewer species of plants and animals. Angiosperms add more than just color to our lives

More information on a world without angiosperms, and a link to the original research here.

Darwin & Plants

After publishing the Origin of Species, Darwin moved into what might be called his botany phase, and he published 7 books on various aspects of variation in plants. In his autobiography Darwin explained his interest in climbing plants:

“I was led to take up this subject by reading a short paper by Asa Gray…. He sent me seeds, and on raising some plants I was so much fascinated and perplexed by the revolving movements of the tendrils and stems, which movements are really very simple, though appearing at first very complex, that I procured various other kinds of Climbing Plants, and studied the whole subject.

Darwin could make sense of this behavior in terms of natural selection. He wrote, “some of the adaptations displayed by climbing plants are as beautiful as those by Orchids for ensuring cross-fertilisation.”

Photo credit: http://darwinsflowers.files.wordpress.com/2009/07/10-4-1_darwin_movements.jpg

Darwin and Insectivorous plants

Odd plants fascinated Darwin. In his spare time he took up the subject of carnivorous—or more properly, insectivorous, plants.

It was sixteen years from his first observations to publication of his book on Insectivorous Plants, and in his autobiography Darwin put a positive spin on the length of time it took him to publish. He wrote.

"The delay in this case, as with all my other books, has been a great advantage to me; for a man after a long interval can criticise his own work, almost as well as if it were that of another person. The fact that a plant should secrete, when properly excited, a fluid containing an acid and ferment, closely analogous to the digestive fluid of an animal, was certainly a remarkable discovery."

Photo credit: http://darwinsflowers.files.wordpress.com/2009/09/5-3-4_insectivorous_plants_drosera1.jpg

Ancient accidental pollinators

Back in the days before plants developed flowers to attract insects to help disperse their pollen, wind was the main agent of pollenation.

However, paleontologists recently argued that some pre-flowering plants had pollen receptors located deep within the plant so that wind-borne pollen would be unlikely to reach them. These scientists suggest that a little-known group of fossil insects called scorpionflies might have served in pollinating these pre-flowering plants.

These fossil scorpionflies (descendants of which are still around today) have narrow, elongate mouthparts suited for reaching far into plants and feeding on fluids, so it is unlikely they could have ingested the large pollen grains. Instead, pollen grains may have stuck to the insect’s head or mouthparts as they fed, and scorpionflies became accidental pollinators—the first known pollinators of pre-flowering plants.

Reference: Ren, D., Labandeira, C., Santiago-Blay, J., Rasnitsyn, A., Shih, C., Bashkuev, A., Logan, M., Hotton, C., & Dilcher, D. (2009). A Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies Science, 326 (5954), 840-847 DOI: 10.1126/science.1178338)

Photo credit: http://z.about.com/d/animals/1/0/n/g/18149_web.jpg