Symbiotic Relationships: Cooperative Relationships Among Animals
How come we can’t all get along? These days you may be asking that question a lot.
If it is any consolation, in the animal and plant kingdoms, there are some great examples of relationships that are interconnected, cooperative and beneficial to both organisms.
A favorite term frequently referenced in biology and ecology is a symbiotic relationship. I guess I love the idea that animals of different kinds may help each other out. Their survival may depend on their collaboration. Predator-prey relationships play on our emotions of fear, disgust, or relief and joy if the prey slips through the predator’s reach. We expect animals of the same species to protect their own offspring and even close relatives. Meerkats come to mind, working together to survey the landscape for threats and sounding the alarm when one is spotted.
But I think as humans we experience surprise and a particular interest when animals of different species interact in supportive or playful ways. The internet is full of pictures and stories of interspecies animal companionship
Symbiotic relationships are significant for the animals involved as well as other animals and the wider ecosystem. Discussions of symbiotic relationship may also be important for highlighting our relationships with our own children, other family members and the community at large. These are not exactly the same thing, as symbiosis refers to two or more organisms of different species that are mutually dependent on one another for survival. Nevertheless, discussing models of helpfulness should inform and impact our children’s understanding of human relations. An awareness of symbiosis may encourage keeping an eye out for helpfulness and compassion.
There are different forms of symbiosis in biology. I think the form known as mutualism, where both partners benefit, is perhaps the best place to start with young children and may be the only form you will cover for now.
Organisms may also be commensal, where one benefits and the other is not affected.
Parasitism benefits one organism at another organism’s expense. At first, this seems just the opposite of what we commonly think of symbiotic. However, strictly speaking, a parasite needs a host to survive and reproduce so its very existence is directly tied to another species.
As mentioned earlier, another relationship often discussed is predator-prey. In this dyad, one organism kills and the other perishes. This and parasitism are often included in textbooks describing symbiosis, but they are distinct, and perhaps referenced as contrasts. So for this activity post, we will only be focusing on mutualism and commensalism.
One more distinction that may be worth bearing in mind is that these relationships may be external (ectosymbiosis) or endosymbiotic, where one organism resides inside of or internal to the other.
Here is a helpful video you can share with your child when describing these types of relationships.
Observe/Compare and Contrast
Symbiosis refers to particular kinds of relationships in nature. As such, you may not be able to ask your child to look for something specific, like a firefly or some seaweed to observe (as we would normally ask you to do in these activities). Instead, she may need to identify patterns over time that will lay the foundation for understanding these associations. Furthermore, observations of symbiosis is a little more difficult than usual as some of the best examples involve animals that you are more likely to find in a zoo than in your backyard.
For example, the Nile crocodile allows a bird, the Egyptian plover, to pluck leeches out of its teeth. The crocodile allows the bird to walk around in it mouth with its impressively large jaw extended open. Rather than snapping down on the bird, it waits until it’s teeth are cleaned. The bird acquires needed sustenance.
Another dangerous animal, or sharks, allows a cleaning fish, called a remora, to attach itself on the shark and extract scraps and parasites from its teeth without devouring them (or mostly without risk). The remora serves the same function for whales, stingrays, and turtles. It is thought that the remora gets food and protection, particularly if hanging with a shark.
Clown fish, who live among sea anemone, an organism that proves poisonous to other fish stinging them with tentacles, is another example. Both provide multiple benefits to the other. The anemone provides the clown fish with food and protection. The clown fish defends against predators, consumes parasites that might do harm to the anemone, and they provide nutrients through their excrement (poop).
Another colorful marine example is the various kinds of cleaner shrimp that crawl over fish and other marine invertebrates picking off parasites and other harmful pests. This often involves crawling into fishes mouths and picking parasites off of their gills.
Oxpeckers, a type of bird, land on the backs of rhinoceros and zebra, eating ticks and parasites off of their skin. If the birds feel threatened, they fly upwards, squawking loudly providing a warning. The birds benefit from easy access to food, and the larger mammal benefits from pest removal and warnings of danger.
Zebra and wildebeest travel long distances together in migrations, providing protection for each other.
Orchids rely on fungi to help protect seeds, otherwise, they cannot reproduce. They also employ a variety of ingenious strategies to attract very specific pollinators
Termites rely on bacteria in their guts to help digest the wood they consume.
Like termites, we have our own “gut bacteria” that are helpful. You may have also heard about our gut biomes or gut flora, or the mix of bacteria in our intestines that help us to digest our food and protect against invasive pathogens. E. Coli exists in our guts to serve these functions and produces vitamin K! We benefit and in return, provide protection and nutrients for the bacteria.
Here are examples of broad categories of symbiotic relationships critically important in most ecosystems.
- Plants and their pollinators.
- Seeds and the animals that disperse them.
- Animals that provide an anti-pest service for other animals.
Has your child observed a bee, butterfly or moth on a flower? Why is it there and why might this be a symbiotic relationship? Does the bee or butterfly benefit (yes, they are collecting pollen or nectar as critical food sources.) Does the flower benefit? Yes, the bee or butterfly carries pollen from plant to plant or from male to female plant parts helping the plant produce offspring by making seeds.
Birds and mammals, such as squirrels, carry nuts or seeds and drop them so the plant benefits. If the bird or mammal consumes the seed, it too will benefit as it needs the nutrition, and often a seed is excreted in its poop, thus dispersed.
So look for insects, birds or squirrels that are assisting plants in their reproduction. Do we play a role in plant reproduction of seed dispersal? Yes, absolutely.
Make lists of various kinds of symbiotic relationships that may be familiar to you and your child. These might be animal-animal, plant-plant or plant-animal relationships.
My favorite version of mutualism is the role that some animals play in providing pest services. I mentioned several of these above.
Here a variety of videos may help describe these relationships:
So with these relationships in mind, as your child investigates animals or plants, or is concerned about her own health, consider focusing conversations on how different organisms in an ecosystem can help one another. Consider how we all get along. Mutualism or beneficial symbiosis is Mother Nature’s subtle way of designing WIN-WIN scenarios.