4. Interdependence

Dear readers, 

Hello (!) and welcome back to the Voice of Prakriti. 

I've been on a break because of health reasons and exam season, but I'm back.  I truly missed connecting with all of you :)
Today, let's talk about Interdependence -  the 4th ecology essential in my list of top 10. This world is home to countless living organisms coexisting and interacting with one another. These interactions could be classified broadly as positive or negative. 

Textbook definition of Interdependence refers to the mutual reliance and interconnectedness of organisms within an ecosystem; where the actions and interactions of one species or population can have direct/indirect effect on other species, and the overall functioning of the ecosystem.

Let's understand types of Interdependence through examples.

1. Competition (-/-)

Imagine a tree in a rainforest. And a lizard. There are a lot of insects present, that can act as a food source for lizards.
Naturally, lizards will compete for these insects. This is an example of intraspecific competition, where members of the same species compete for the same resource.
What would you do in this lizard's situation ? You would - i. fight for food everyday, or
                                                                                              ii. try to find another way out ?

Well, what eventually happened is that some lizards adapted to eating insects found on forest floor, while others specialized on hunting insects present on trees. Instead of competing constantly, they tried to find a way out. This process of adaptation is what we call specialization. 

Fig 1. Specialization of Anole lizards
(source : Internet)

I feel obliged to talk about this example since we are on this topic. This is the case of Darwin finches (Finches are a type of bird) which Darwin had used to prove the theory of evolution and natural adaptation.

Fig 2. Specialization of beaks of Darwin finches based on the food source (some began to eat only seeds/insects/plant parts and their beaks evolved accordingly) , in order to avoid competition. 

   (source : www.visiblebody.com)

Competition can also occur in between different species. Examples would be squirrels and woodpeckers fighting for same holes for nests/ storing food. Lions and cheetahs fighting for the same prey (antelopes or deers). These are examples of interspecific competion, where competition occurs between two species.
The effect of Competition is generally negative for both species (-/- interaction), as each would've  thrived better if the other weren’t present.

(The symbols "+," "0," and "-" are used to represent the outcomes/effects of different species interactions on the interacting species involved.  The "+" symbol indicates a positive or beneficial effect on the species. The "0" symbol indicates a neutral effect on the species. It suggests that the interaction has no significant impact or consequence for the species involved. The "-" symbol indicates a negative or detrimental effect on the species.)

2. Predation (+/-)

As the word suggests, it literally means attacking a prey. Examples - Owl hunting mice, lions hunting deers, cats hunting mice, etc. But, plants can be predative too, you know ? You must've heard of the Venus flytrap? I've always had a strange fascination towards carnivorous plants. They sound cool, and different. 

Fig 3. Diagram of a pitcher plant, luring an insect using a pleasant smell. Once inside, the lid snaps shut, and the insect is digested. (Made in Canva)

In predation, clearly one species benefits, and the other is harmed, hence (+/-) interaction. 

3. Parasitism (+/-)

The main difference between predation and parasitism, is that predation involves killing the prey, while parasitism does not. The parasite needs the host to survive; and depends on the host's metabolism for nutrients. 

Now parasites can live on the surface of the host, or inside the host. Parasites living on the surface are called ectoparasites. Examples include fleas - they often live on your pet dog's/cat's fur. Another irritating example would be lice on your head. These don't particularly cause dangerous diseases, but cause itching, infections and in extreme cases, illnesses. 

Endoparasites are a different story. They cause the host to fall severely sick. Most common example - single celled parasite called Plasmodium known to cause Malaria. Plasmodium is transferred into the host by mosquito bites. Once inside the body, they destroy red blood cells. Alarmingly, there are many other parasites that cause even more severe diseases. In this case, the human serves as the host, Plasmodium is the parasite, and the mosquito acts as the vector.

Interestingly, some parasites require not just one, but two hosts to complete their life cycle ! Taenia solium (pork tapeworm) is an example. Its life cycle involves both pigs and humans. This typically occurs when humans consume undercooked pork contaminated with the parasite's larva. This larva grows into adult tapeworms in the human intestine; causing pain, diarrhoea, malnutrition. 

4. Mutualism (+/+)

As the name suggests, both species benefit from this interaction. It's like a win-win situation where each one helps the other.
A very important example is the mutualism seen in bees and flowers. 

Fig 4. Bees collect nectar from flowers, which they use to make honey. In the process, the pollen grains stick to the bee's body, and when it moves to another flower, it transfers the pollen, helping the plant reproduce. (Made in Canva)

I want to take a moment and talk about why pollination is an important concept for all of us to understand.
Imagine pollination to be nature's invisible workforce. Pollination ensures that about 75% of the food we eat (fruits, veggies, nuts, and even coffee) comes on our tables. Without these tiny helpers, our plates would look almost empty; as they are responsible for vegetables, fruits and crop growth.
Think of it like a free service - by millions of bees, butterflies, birds, and bats; except that it is'nt actually free. Pollination is a vital ecosystem service valued at $235–577 billion annually. 
[An ecosystem service simply means the service/benefit nature provides, for humans. Humans calculated the economic value of these benefits - and we actually owe nature THAT much; annually.] 

You see why it is important to #savethebees ? You can do your own bit by supporting organic farming and locally sourced honey; they all promote pollinator-friendly practices. 

5. Commensalism (+/0)

"Commensal" means an organism that lives in close association with another organism, benefiting from the relationship without harming/significantly impacting the host organism. This type of relationship generally has a large host and a small commensal.

Imagine a whale swimming in the ocean. Tiny animals called barnacles stick to the whale's skin. These barnacles can't swim, so by attaching to the whale, they get a free ride and can catch food from the water as the whale moves. The whale doesn’t mind the barnacles being there—it isn’t helped or hurt by them. This type of relationship, where one benefits (barnacle) and the other is unaffected (whale), is called commensalism.

Fig 5. Host -Whale, Commensal - Barnacles

 Even though Barnacles seem small and unimportant, they help keep the ocean healthy by filtering water and providing homes for other tiny sea creatures. They’re like nature’s little cleaners in the marine world.

6. Amensalism (-/0)

Amensalism is the opposite of commensalism. In this relationship one species is harmed, while the other isn’t affected at all. Sounds confusing ?

For example, large trees like walnut (eg. Black walnut trees) release chemicals (called jugalone) into the soil that stop other plants from growing nearby. The tree doesn’t gain or lose anything, but the smaller plants are harmed because they can’t survive. The fancy word for this phenomena is 'antibiosis' - when one organism produces chemicals that harm or stop the growth of another, without affecting itself.

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Now that we have explored (and understood) different kind of interactions organisms can have with each other, we are one step closer in unraveling the intricacy of nature - and why disturbance is created when humans knowingly/unknowingly disturb ecosystem dynamics with their actions. 

The next blog will be on Rivet - Popper Hypothesis; and I promise it's interesting ( less technical terms and more 'mind blowing-y' terms as we connect the dots). 

See you soon !