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Showing posts with label symbiosis. Show all posts
Showing posts with label symbiosis. Show all posts

Wednesday, March 3, 2010

Let’s All Just Get Along!

It's time for Bio 101 - let's talk about symbiosis (mainly because I am constantly trying to reference it in other posts). Symbiosis is a very straightforward topic, but it is still really interesting when you find examples of it in nature.

Symbiosis is a term used by biologists (specifically ecologists) to refer to the close and often life-long interactions between two or more different species. These relationships can occur between any living thing and examples are found everywhere.

Symbiosis is divided into three specific types of relationships: mutualistic, commensal, and parasitic.

Mutualism is a relationship where both (or all) species involved benefit from the relationship. Remember yesterday's post – I told you how we have lots of bacteria living in our colon? Well our relationship with these bacteria is a mutualistic relationship. The bacteria help us break down and digest food. In exchange we provide it a safe and happy home with plenty of food and water. We are both gaining from this partnership. By far the most popular example of mutualism is between sea anemones and clownfish. Clownfish have evolved an adaptation that makes them immune to the stings of the sea anemone. When a clownfish needs to hide from a predator, it can swim deep inside the anemone for protection. In exchange, the clownfish protects the anemone from its predator, the butterflyfish.

Commensalism is a relationship where one species benefits while the other species is not affected (positively or negatively). An example of this is the relationship between the cattle egret and grazing animals. As horses, cows, sheep and other livestock trample over fields feeding, they tend to stir up a lot of insects. Knowing this, the egret follows herds of animals and eats all of the insects they stir up into the air. The egret uses the livestock for an easy dinner and the livestock leave unaffected.

The last relationship is parasitism. This is when one species benefits at the expense of another. This is a tricky relationship because parasites need to be careful that they are not so damaging that they don't allow reproduction of their own species before they kill their host species (a parasite doesn't always kill its host). Parasites also have to be smart because no species is going to just allow itself to be exploited. Parasites need to be able to handle fighting off immune responses and other protective mechanisms of the host species. A popularly known human parasite is the tapeworm. Ugh, worms gross me out so I am not even going to talk about them.

Scientists did what scientist do best and broke down these main categories even more, but this is the basics. A nice easy little hump day treat!

Wednesday, January 20, 2010

I shall call him Squishy and he shall be mine and he shall be my Squishy


Good morning everyone! As a little hump day treat, I’m going to tell you about one of the prettiest little animals in the ocean: the blue-ringed octopus (Hapalochlaena maculosa).

There are at least 10 members of the blue-ringed octopus family and they all live in the Pacific Ocean between Japan and Australia. Like many other octopuses, the blue-ringed octopus spends its day sleeping and its night working the tidal pools – hunting for crabs and shrimp. They are tiny little things, with the biggest family member only being only about 15cm long (about 6 inches) and coming in at whopping 28 grams (0.06 lbs). If you catch one of these little buggers resting it will look wrinkly and covered in brown spots, but the minute you spook it or get it agitated, the brown spots will darken. Specialized cells around each of the brown spots then create bright iridescent blue rings that pulsate. Scary looking, huh? Well I hope you think it’s scary – so scray that you leave the little octopussy alone.

If this octopus cannot scare you away with its colors, don’t worry, it will still get you. The blue-ringed octopus is considered one of the most poisonous animals in the world. One bite from this tiny little swimmer will inject enough toxin into an adult human to completely paralyze and kill them in minutes. There is no antivenom available. The fun thing about this toxin is that it is not actually made by the octopus.

You are about to behold an example of Mother Nature making best friends. Inside the salivary glands (throwback to yesterday) of the blue-ringed octopus lives a strain of bacteria that produces tetrodotoxin – the toxin that puts you into respiratory arrest. The bacteria produces this toxin (which the octopus has evolved a resistance to) to help the octopus survive. In return, the octopus provides the bacteria with a happy and safe home. In science, two organisms working together to help each other survive is known as a symbiotic relationship (more specifically a mutualistic symbiotic relationship since both are benefiting and neither at the expense of the other). You have seen relationships like this all the time, but this is one you may not have ever thought of.

So what have we learned today? Organisms work together, evolution can help build these relationships, a bunch of random facts about octopuses, the fact octopuses is the proper plural form of octopus, and don’t touch brightly colored things.