What is symbiosis?

Symbiosis in the natural world is described as the close interactions between different species or the relationship of species living together (Oulhen et al. 2016).  

It can be found all throughout the living world and wherever there is life there is probably at least one group of symbiotic species. It is usually why bees pollinate plants, parasites invade animals, how plants get nutrients from the soil and even possibly an important driving factor for the evolution of species and life as we know it today – but more on that in the later blogs (Bronstein et al. 2006)(Gilbert 2019)(Douglas 2014)(Aanen & Eggleton 2017)(Lopez-Garcia et al. 2017).

Why is it important?

Symbiotic relationships are often so heavily relied upon that an organism cannot grow as it normally would without it’s symbiotic partners (Gilbert et al 2015). This not only affects the species holding the relationship but can also be essential elements of entire ecosystems (Heide et al. 2012). Understanding these close relationships can also help us to understand how these organisms function, how they evolved and how they may adapt to changes in the future.

Mutualism: A bee collecting pollen from a flowers for food also pollinates the flowers when it transfers pollen from one plant to the next (Bronstien et al. 2006). (Photoreith 2020)

The Types of symbiosis

According to Anton de Bary’s original definition of Symbiosis, there are three main categories of symbiotic relationships: Mutualism, Parasitism and Commensalism (Oulhen et al. 2016). Symbiotic relationships can also vary between these categories (Oulhen et al. 2016).

Mutualism is a relationship where both of the symbionts benefit (pictured above).

Commensalism: The Pilot Fish (Naucrates Ductor) recieves protection from predation while the Shark (Carcharhinus Longimanus) is unaffected (Mangunsen & Gooding 1971, Fuller & Parsons 2019). (Peterkoelbl 2006)

Commensalism is where one symbiont will benefit without the other organism being affected. 

Parasitism is where one symbiont will benefit to the detriment of the other.

These three categories can be divided further into either ecto-symbionts (organisms living outside of each other) or endo-symbionts (one living inside the other).

In this weekly blog I will go through some cool examples of symbiosis and look at how symbiosis affects the evolution of species and how these relationships help us understand the world around us. Hope you enjoy! 😊

...Check back next week for some classic examples of symbiotic relationships we can easily see: Ecto-symbiosis in animals and plants.