"A tree is a wonderful living organism which gives shelter, food, warmth and protection to all living things. It even gives shade to those who wield an axe to cut it down."   ― Buddha

“The evolution of plants is an important chapter in the history of life. However, it’s a pretty dull chapter, so we’ll skip it”   ― Tom WellerScience Made Stupid

 “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff....If you wish to make an apple pie from scratch, you must first invent the universe.”   ― Carl Sagan, Cosmos

There is no doubt about it...I love bees! They are beautiful animals and so diverse in terms of the number of species, and their various life histories, that one can never get tired of studying them (okay, admittedly I’m biased). I consider myself very fortunate to be able to pursue scientific research on bees from many perspectives, although it’s their importance as crop pollinators and the great concern of losing this “economic” service that has really brought them into the limelight in recent years. But it’s really the vital ecological service that bees provide that I wish to discuss here, though perhaps in not so direct a manner.

Pollination is required for the successful reproduction of flowering plants, and for the vast majority of them, insects (especially bees) are the main pollinators. We should not take this ecological service for granted as it is responsible for much more than we typically appreciate, although Buddha certainly did, through his observations on a tree, as noted above. In fact, this ignorance of plants is why I choose to include the second, rather humorous quote; as a society we typically do not notice the complex, vital processes taking place around us, nor do we fully appreciate all that we, as living things, obtain from our photosynthetic co-inhabitants of this planet. So, let’s consider plants, and specifically why we all need them.

First, the most obvious thing from our perspective is food – plants directly provide us with a cornucopia of goodness. I truly think that one could eat a different fruit and/or vegetable every week of their life! When we eat apples, mangoes, cherries, strawberries, blueberries....we have pollinators to thank. However, there is also the indirect pathway to consider, as much of our forage crops (i.e., used to feed livestock) come from the seeds of plants which resulted from insect pollination (although one also has to thank the wind for pollinating many of our cereal crops as well). But plants form the base of food pyramids in terrestrial ecosystems, and without them, the millions of other living things also dependent on them would not exist. This is evidenced by the huge losses of biodiversity and ecosystem collapse associated with rapid loss of plant communities (e.g., deforestation), and even with changes from natural, complex ecosystems to more simplified ones (e.g., monoculture). This is about more than just food though...plants also provide structure to our lives, materials that we and other organisms can turn into homes, and for us, furniture, paper etc. As a species, we also get medicinal, cultural, and recreational benefits from plants. Thus, it’s true that we, and almost all other terrestrial species, cannot live without plants. And here, I’m just touching the tip of the iceberg.

However, all these things, especially from the human perspective, are the more recent (geologically speaking) benefits of plants. It is through photosynthesis that the real importance is realized. Some 30% of the oxygen in the atmosphere is produced by terrestrial plants. Lucky for us, the remaining 70% of oxygen is produced by single-celled marine algae, as we routinely destroy plant community diversity on land. Think about it, photosynthetic organisms use energy from sunlight to bond the carbon atoms from carbon dioxide molecules created in stellar explosions throughout the universe millions of years ago (and at distances almost too great to comprehend) to hydrogen atoms, ultimately creating carbohydrates (i.e., sugars). It is through the chemical bonds between these hydrogen and carbon atoms that solar energy is converted into a form than can be used to build all that is alive; the byproduct of this solar-charged chemical process is oxygen, which ultimately made life on Earth as we know it, possible in the first place.  Although one could argue that single-celled photosynthetic organisms were largely responsible for this over the long term, it is really the rapidly evolving, fantastically diverse terrestrial plants that make the lands of the Earth so teaming with life. Ensuring that these plant communities continue to thrive requires that they can reproduce successfully.