Arboretum Director William ‘Ned’ Friedman visited San Sebastian, Spain in October for the Passion for Knowledge festival, where he shared his thoughts on evolutionary biology, and his passion for plants.
El País published an article about Ned’s visit, shared here in English. The original, written by Adeline Marcos of the Sinc Agency, was published in Spanish.
“If you don’t care about plants, you may not know how to take care of another human being.”
Every year, 2,100 species of plants fascinate the 250,000 people who visit the botanical garden of Harvard University in Boston. Its director confesses that the plant world will never cease to surprise him.
Adeline Marcos Sinc Agency
Hundreds of children visit the Arnold Arboretum, the botanical garden of Harvard University in Boston (USA) every year, where there is a rule: everyone is able to teach, from university students, to staff and scientists.
One of them is the biologist William Friedman, who visited Spain during the Passion for Knowledge (P4K) festival held in San Sebastian. Passionate about plants, Friedman is a professor of Organismic and Evolutionary Biology at Harvard University and has dedicated his entire career to the study of the evolutionary diversification of plants.
Question. It has been shown that plants have special relationships and help each other. In that sense, are they better than us?
Reply. From the point of view of an evolutionary biologist, a large number of premature deaths occur between plants. For every bird you see through the window, 199 have died. For each plant you see, how many seeds have fallen or grown a little and have not succeeded? Plants do wonderful things by cooperating with each other, but sometimes they have a dark side.
Q. What aspect of plants has surprised you most throughout your career?
R. I have had incredible surprises throughout my life, especially with the study of the evolutionary origin of flower plants, which are a very recent group, the youngest. How is it possible then that they are everywhere? I studied the inner tissue of the seeds in which the mothers put their food and then goes to the embryo. It is something we have tamed to eat, the so-called endosperm. We eat a grain of rice or corn because it is full of nutrients. I have discovered many things about this process.
Q. How what?
R. That mothers and fathers disagree about the nutritional contribution of that tissue, and we can see it with genetic analysis. When I look at a seed, I can see the genes of the mother and the father, how they discuss how much food they should have. I’ve been wondering for twenty years if fathers and mothers discuss how to feed their offspring and in the last five years we have discovered it…
Q. And who wins?
R. Ah [laughs], because the truth is that it depends. That is the question. In general, fathers are sperm donors and ovum mothers, but they also have to feed. One is more involved than the other, which only gives its genes. This happens with animals, but also with plants.
Q. So what does a father want when he gives his genes to a mother’s seed?
R. That seed has all the possible food. Mothers have many seeds, but they select and reject those that they think are not good because they have limited resources and must decide where they invest their food.
Q. And when analyzing those seeds, what else can you see?
R. In molecular genetics studies you can even see how all this happens. Because they make different investments, fathers are selfish and mothers try to make universal decisions. If a mother with one hundred seeds only has food for fifty, which ones will she invest in? You will wonder which ones are the best. The females recognize the seeds that may be genetically related and close the arrival of the pollen in a biochemical way. They are continuously filtering parents. It is one of the great stories of plants and I don’t think many people know her.
Q. When you reject a parent, can you choose another?
A. In the case of the pines, which pollinate by means of the wind, the mother receives the sperm of many parents and thus can choose. If insects come into play, parents of different backgrounds come to each flower and mothers make them compete with each other.
Q. But how do they know if they are good parents?
R. They know the father’s genetic attributes, it’s amazing. In some cases, they will know if the father is a direct relative; in others they will know if it is not a good match, and then the mothers will stop fertilization. And even when fertilization has started they can abort the seeds. For many years I have enjoyed understanding that plants, such as humans and other animals, have conversations between parents and make decisions.
Q. When did you start to be interested in plants?
R. I grew up in the field, but it was in the Biology classes of the institute that I became more interested. It wasn’t good, but I liked it so much … One morning we were in the lab and we had a hairy pig dead in formalin that we had to dissect. I did not like anything. I had no idea how the animals worked. So I thought I probably shouldn’t be a biologist [laughs]. But suddenly the plants appeared and I felt an instinctive and deep connection with them. I was very lucky to experience that feeling with the plants and move on.
Q. So the plants actually chose you…
R. The truth is yes, and I feel very fortunate to have discovered their world [Laughs].
Q. Of all the characteristics of the plants, which one of them was unimaginable for you when you started studying them?
R. Plants do many strange things. Do you know ginkgo? It is a very old tree present in cities. It has two sexes (those who make pollen, males, and those who make seeds, females), but you will not see them together in Madrid. You will not see any seeds in the city and the reason is that they smell very strong, so people only plant males. In the Harvard botanical garden we have females and they smell like vomit because of the butyric acid inside. The seeds are scattered on the ground and it smells like everyone in the city has vomited there. It is very powerful.
Q. And what sense does it make for females to do this?
R. Some extinct animal thought they smelled very good and began to eat the seeds to disperse them. The plant was left with that code, which smells fatal to us, but you can see all kinds of flies, which disperse seeds, flying around.
Q. It has been his way of adapting and surviving, but in general the plants face many threats …
R. Yes, as the invading pathogens that move on wooden pallets transported on ships. As we move things throughout the world and sometimes we are not careful, we continue to introduce threats that could annihilate an entire species. They can be insects, fungi or bacteria in the most unexpected places, like the soles of my shoes.
Q. All this will worsen due to the climate crisis.
R. Of course. Climate change aggravates the situation. I can give you an example. In the botanical garden we have magnificent beech trees that suffer from a disease caused by an invasive fungus. Trees can fight the epidemic, as you and I do if we are healthy, but what happens if we are stressed, we are older or we eat badly? In this sense, plants are exactly the same as humans. Three years ago we had the worst drought in the area. During two months we suffered aridity conditions and in the two following years, the sick trees ended up perishing. The disease won. The beech trees were so stressed by the drought that they couldn’t fight. We had to bring down trees three meters wide that had died. And this is being seen with insects and birds all over the world. The question is whether this worries us or not.
Q. Why worry about plants, many will ask?
R. Sure, it’s not us. Birds are not us, insects are not us. If you can’t worry about a plant, you may not be able to take care of another human being. It is said that we must be concerned with nature because if we do not do so, we will lose the ability to feed the world, but I do not think it is the primary reason.
Q. And what would it be?
R. To think that all these organisms are our food and depend on our exploitation is to be short-sighted. There is a deeper value. We must worry because we share the Earth with them.
Q. The plants have been adapting for millions of years, but do they still maintain that capacity now?
R. Plants can adapt, yes. Can you do it quickly? Yes. Can they adapt to the speed at which we are changing the planet? We will find out. 20,000 years ago in Boston there were neither plants nor trees, there was a glacier, and now the city is full of vegetation. Plants move, change, grow and adapt. However, the changes we are introducing now are so rapid that certain ecosystems will collapse.
Q. What will happen? Can’t we go back to the starting point?
R. If it finally goes wrong, it will certainly be our fault. We will not be able to return. It will be a new future.
Q. And what will that future be like?
R. I don’t know … Maybe it will be one without humans. But I am sure of one thing, and that future will be very rich thanks to evolution. The most incredible thing in life is that it is resilient. The balance can return. Maybe we are not resilient enough, but in millions of years it is possible that the planet remains green and still has animals. If we want to remain part of it, we have to be more careful.
Q. We may now be beginning to change. Have you not noticed?
R. Yes, there is increasing environmental awareness. 40 years ago, when I started my studies, scientists did not speak to the public, they thought it was not part of their work. In the last 20 years, scientific journalism has become a very powerful way to help scientists – who were not good at explaining things – to connect with people. Being a scientist is not just doing science. We are citizens responsible for raising awareness.
Q. Will we ever know everything about plants?
R. I don’t think so… There is a poem by Alfred Tennyson called Flower in the Crannied Wall of 1863 that is the answer to your question. If I could fully know each of the plants, I would know the entire universe. But we can not. Each plant is so complicated that it is impossible. That makes nature so wonderful.