Discover More: Symbiosis

Let's look at some of the fabulous ways that different organisms have evolved to cooperate, sometimes to the extent that one or both (or all) partners would not survive without the other. Discover more with Linnean Learning.

Published on 17th January 2022

The Discover More series is a collection of animations, blogs and interviews exploring a wide variety of topics to enrich your appreciation of the wonderful natural world that we are a part of. There are seven topics which will be released over several months and the animations are best viewed via Instagram @LinneanLearning.

Symbiosis, a bobtail squid

Screenshot from our animations on Instagram.

We often think of evolution as harsh. "Survival of the fittest." A competition where each species is out for themselves. But nature is much more complex and dynamic than that idea might make us think.

Nature is brimming with relationships, an erratic web of interactions which tie one species to another in both delicate and brutal ways. For example, how bees pollinate flowers in the process of getting food; both organisms benefitting from this relationship; they co-operate in each other’s life cycles, and their evolution is tightly bound; and thus they’ve co-evolved to rely deeply on each other. We call this cooperation between mutualism.

This month we are highlighting some of these fascinating relationships. We’ll be talking with Professor Kleber Del-Claro from Universidade Federal de Uberlândia about the work that he does on beneficial symbiosis in the tropical savanna.

Read on for a couple of symbiotic examples below, watch our short animations on Instagram, Twitter or TikTok and enjoy our interview with Kleber on those platforms or as a transcript (see below).

Holy smokes! In 1977 a submarine went to investigate the sea depths near the Galapagos Islands to try and prove a theory about undersea volcanic activity. Deep below, where light couldn't reach, they found the volcanic activity that they were looking for in the form of hydrothermal vents called black smokers - but they also found many other surprises. Our understanding of biology at the time meant they didn’t expect to find any life where there was no sunlight. However, they found a teeming ecosystem, fuelled by the chemicals pouring out of the vents rather than by sunlight. One incredible organism they found is called Riftia pachyptila, commonly known as the giant tube worm. These animals have no mouth and no digestive tract but manage to thrive in these hot and deep conditions because of the host of bacteria they keep in a special organ, which convert the sulfur released by the vents into nutrients for the worm in a process called chemosynthesis.

The Wood Wide Web! Many trees and other plants are connected to each other through a special network, linking their root systems through the thread-like “hyphae” of fungi. These connections between plant roots and fungal hyphae are called mycorrhizae.. If you’ve ever pulled up a plant from the soil and seen a tangle of pale, yellowish, hair-like threads attached to the roots, these are the fungus. Over 90 % of all land plants rely to some degree on this relationship to fungal partners in order to extract minerals, water, and nutrients from the ground. In return the fungus gets sugars and other resources. The fungal partners are key in breaking down soils and in helping the individual plants form associations with other plants in the environment; via these fungal root systems plants are able to send signals to each other about different kinds of threat, such as nutritional needs or various pests or diseases, so that other plants can send food via the network or chemically try to defend themselves from any on-coming threats. The mass associations between trees via their fungal partners sometimes gets called the Wood Wide Web, drawing a comparison to how this behaviour is reminiscent of interconnectedness of the internet (the world wide web).

Lighting up the dark!
The Hawaiian bobtail squid has a special light organ that glows to match the luminosity of the moon, so that when it hunts at night, it casts no shadow, evading detection from its prey. However, it doesn’t generate this light by itself. Its light organ houses a symbiotic, bacterial partner, Aliivibrio fischeri. This bacteria collects sugars and amino acids from the squid, whilst providing the squid its light. This relationship has become a popular model for scientists to look at the co-evolution of animal-bacterial relationships.

How a powerhouse settled down in a cell!
All Eukaryotes, that’s all animals, plants, and fungi (and some other mixed-bag organisms sometimes grouped as Protists), are the result of an epic (and minuscule) form of symbiosis. We all have the organelle mitochondria in our cells, sometimes called “the powerhouse of the cell,” which uses oxygen to fuel a lot of activity within the cells. But the ancestor of these mitochondria used to be a free-living bacterium that somehow (probably through being ineffectively eaten) wound up stuck in another free-living primitive cell. These two organisms fusing into one organism is the ancestor of all organisms with a nucleus, from you, to that tree through the pavement, to your friend’s cat, to the mushrooms in a full english. Some scientists speculated this might be the case from the late-1800s onwards, because of the visual similarity between mitochondra (Mt) and certain bacteria under the microscope, and the fact they seemed to replicate separately to the cells’ divisions, but it wasn’t til it was empirically confirmed that Mt have their own genome, separate from the genome in the nucleus of the cell, that those scientists were vindicated in their hypotheses. This process, where two or more organisms fuse to become an entirely new kind of organism, is called symbiogenesis.

What do you think about these strange partnerships between different organisms? You can let us know through our Instagram, Twitter or TikTok, or even send us an email at

Discover More!

An interview to an expert in symbiosis

Kleber Del-Claro
Kleber Del-Claro

We spoke with Professor Kleber Del Claro from the University Federal de Uberlândia on the subject of symbiosis.

The following text is an edited interview between Kleber and our Research Officer, Zia. You can view this interview on Instagram or TikTok
Could you introduce yourself to our audience?

My name is Kleber Del Claro. I am a professor at the University Federal de Uberlândia, a type of public university in central Brazil, we are hosted exactly in the centre of Brazil. I am a biologist and I have worked in ecology since 1992, in the tropical savanna. I work in biodiversity, and mainly look at the interactions among plants and animals that sustain the biodiversity in the tropical savanna.

Could you tell us what symbiosis is?

Yes, symbiosis is a type of relationship in nature. And there are several types of symbiosis. For example, parasitism is a symbiosis that is a relation among two organisms in which one organism is gaining advantage against another, drawing resources from that organisms, whilst the other organism is losing out. And for example, mutualism is another type of symbiosis, in which both organisms benefit from the relationship. So, symbiosis is generalised in nature, and one important thing that we have to perceive is that we are living organisms because we do symbiosis. Okay, symbiosis is life, and mutualism is life. for example, in each cell of our organisms, we have a mitochondrion living inside, and the mitochondria is a symbiont, is an organism that was phagocyted by another organism, and then living together in a community. So for example, if we remember Lynn Margulis, in The Symbiotic Planet, a book from the 70s, Lynn Margulis said to us, we are a community of microorganisms, living together with a common mind and a common thinking. So symbiosis is life, it is everywhere in nature in different forms, it is structuring biodiversity, it is structuring the environment as a whole.

Could you describe for us what it is specifically that you research?

I study plant-animal interactions in the tropical savannah and I also study animal behaviour; two lines in the same laboratory. Okay, so we study for example, plants that that have extra floral nectars. extra floral nectaries are the glands of nectar that are not produced to attract pollinators. They are in other parts of the plants that are not flowers, for example, the leaves and stems and nearby buds. And it attracts predators, like spiders, like ants, that goes to the nectar to feed on nectar because nectar has water, amino acids and a lot of substances that are very useful to animals in nature. So receiving this food from the plants, these predators offer to the plants indirectly protection, protection against predators and parasitoids and elsewhere. And so this builds a very complex network of interactions. And it's one plant with this system, another plant, lot of plants, other plant other plants and all these plants are connected, they are connected by these mutualists that are interacting with the plants. So I study together with my students and colleagues obviously, the network of interactions between these organisms, that structures and maintains biodiversity. And the other side of the research, I study behaviour, the behaviour of these organisms, how behaviour is important to stabilise to maintain the interactions and how behaviour so indirectly is responsible for the maintenance of biodiversity in several ways.

What made you first get into ecology or or biology?

When I was young, when I was a kid and a teenager, my father left Our family and my grandmother brings me and my brother to another city to study another city and to do the live things in another city. So I grew up with my grandmother. And so in the pool in the backyard of my grandmother to gain money. We are poor in that time, I was raising fishes, guppies. And I was raising fishes in tanks and producing new individuals producing these new types of guppies with different colours, and selling them to the markets, to the aquariums and this type of thing to have some money. So when I was at the time to go to the university, a friend invited me to see a class in university, and I saw a class of zoology with a professor that was working with fish, and working fishes, I consider that super interesting because I thought, what, what are you're doing the backyard of my grandmother, this guy is doing to gain money and to, to be a professor in university. At the same time, I began to know my wife, and the mother of my wife was a biologist. And she told me that biology could be important. The biology could put the work ahead and showed me a lot of things about biology. So through my grandmother, through my mother in law, and through a friend that invited me to see a class at the university, I discovered biology.

Could you speak to any joys of doing science or being a scientist, anything that's been uplifting?

I think that, to me, the most pleasure in my career, the best to me, is to put other people on good path for life. To me, it's more important than publishing an amazing paper in the journal of ecology, for example. This year, I have two papers in the journal of ecology, and another in the Journal of animal ecology. Oh, it's great. It's marvellous, it's wonderful. I am very, very happy with this. But I am more and more happy because the first author is a guy that was poor like me, a young guy, very, very intelligent. And this guy was working in free markets in the streets. When he gains to the University and at the University he learns English with me, he learnt how to do science, and nowadays, he is an amazing scientists. So to me, what is the most important to me is to help these people to have a future because they will gain lots of money, they will do good research for the world, and they will produce a better world for all of us.

Young people seem to be becoming more ecologically aware, and questions of ecology and biodiversity are more in the public discourse. And I just wondered, was that your impression as well? And what do you kind of see for the future in terms of ecology and your research?

So it's very problematical situation that we're living today. So I encourage people young people, to study ecology. to protect nature. We need to protect nature because nature is our health. This is the only planet we have. We will not be living on Mars. We will not living in Centauri Proxima. We are living here. And for a long time, perhaps.