Maybe you’ve noticed that sea sponges don’t get a lot of fan fare among the public. Let’s be honest, they are not very hot in the popularity contest – we just don’t think of them that much. That being said, regardless of how often they dwell in our collective consciousness, sea sponges are one of the world’s most successful and fascinating creatures.
They move without muscles, and react to threats without a nervous system. They vary greatly in size and color, and some are carnivorous. A number of them have existed for hundreds of millions of years; while some individuals can live for thousands of years. We know that some trees can live for thousands of years, but for an animal it’s incredible. If you continue reading, you will be shown more interesting facts about sea sponges that you’ll be amazed to know.
No Muscles, No Problem
Sponges are permanently attached to wherever they happen to be. This can be coral, a rock or the sea floor. A few move, but not the way you might imagine. These ancient creatures do not have any muscles to help them move – or any other organs for that matter. They move by way of cell locomotion.
Moving one to four millimeters a day is too slow for the human eye to detect. When you compare that to how fast grass grows, which is just over one millimeter an hour. You have a much better chance seeing grass grow than notice a mobile sponge actually move.
This amazing type of locomotion is too slow to detect with the naked eye – it takes place at a cellular level. The cells do this by protrusion, attachment and retraction. (Encyclopedia of Life Sciences). Structures inside the cell called micro tubules (which are also responsible for cell support, cell division and organelle movement) give the cells the different shapes that will determine their direction (Encyclopedia of Life Sciences).
This amazing feat clearly shows how resourceful life is. The intelligence of the cell is evident by this process. What does that say about intelligence in general? I believe it is not restricted to the brain, or to any organs in particular. It seems to dwell where ever life exists – regardless of its complexity.
Let’s remember that when sea sponges first appeared on the planet, organs were not yet a product of evolution. Before more complex animals arrived equipped with muscles, cells moved around their environment using more primitive methods. The sponge today is a living bridge between cell locomotion and movement by muscle power.
Plant or Animal
By the looks of it, sea sponges remind us of plants – they generally don’t move, come in a variety of dazzling colors, and lack any sort of organs, including a nervous system. However, they can respond to threats by releasing toxins and/or spicules; in order to defend against predators like the sea cucumber and/or parasites.
These champions of evolution were the first animals to appear on earth (Independent). This makes them the sister group to all animals here on earth – since they were the first multi- cell organism. The next time you are ready to do some dishes with a natural sponge, you can thank your sister group. Please make sure it was harvested from a sustainable source. So as to continue to provide great sea sponges while keeping the sea healthy.
Some are Carnivorous
For those sponges that live in the dark depths of the ocean or in underwater caves, getting food is more of a challenge. They must come up with a different way to meet their nutritional requirements – like catching live prey. Their body plans have been modified for this new method of getting food. Instead of filtering out bacteria and dead plankton from the water like most sponges, these catch small animals like crustaceans, from the water. The sea sponge on the right uses its ray-like protrusions – which radiate from a central disk – to snare its prey.
Predatory sponges are not only found in great ocean depths. All are, however, found in waters with a low nutritional content. This is generally where the sun’s rays have a difficult time reaching. Making filter feeding difficult.
Great Range in Size
Another of the many interesting facts about sea sponges is their great range in size. They vary from about 3 cm to around 12 feet long and 7 feet wide (The Washington Post). The smallest is a little longer than two aspirins put side by side; while the largest is a big as a minivan. This gigantic specimen was discovered in the waters between Hawaii and Midway Atoll, at about 7,000 ft below the surface (The Guardian).
Scientists think this particular specimen could be thousands of years old. Sponges don’t have growth rings like trees; in order to determine how old one is, a simple radiocarbon dating method is used. Radiocarbon breaks down at a predictable rate, and scientists can calculate the age by identifying how much of the radiocarbon has disintegrated up to that point. This method is also used to date many materials, such as fossils and rocks.
Although they look like and behave like plants, they are actually animals; yet, they don’t have organs or a nervous system. In order to protect themselves from would be predators, they employ chemical and physical defenses. It’s interesting to see that they can sense and react to their environment without the help of eyes, nerves or even a brain
Due the low level of nutrients in some parts of the ocean, some sea sponges have evolved new methods of acquiring nutrition. These will catch much bigger prey than bacteria – like crustaceans, by actively snaring.
All sea sponges vary greatly in size. They range from a couple of millimeters to as much as a few meters. A large sponge can be up to several thousand years old.
These phenomenal animals don’t exactly fit our conceptual mold of what either a plant or an animal is. They represent a true evolutionary achievement. It is perhaps due to this nonconformity, if you will, that they have been so successful.
Let me know what you think about Sea Sponges? What do you think that such a relatively simple creature has been so successful? What does that say about success? Please leave you comment below.
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