Starlet sea anemone facts for kids
Quick facts for kids Starlet sea anemone |
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The starlet sea anemone (Nematostella vectensis) is a small sea animal. It looks a bit like a flower, but it's actually a type of sea anemone. These creatures are usually found on the east coast of the United States. You can also find them in some parts of England and on the west coast of the United States, where they were introduced. They have also been seen in Nova Scotia, Canada.
Starlet sea anemones live in shallow, slightly salty water, like in coastal lagoons and salt marshes. They often bury their long bodies in the mud, leaving only their tentacles sticking out. Scientists study this anemone a lot in labs because it helps them learn about how animals develop. However, in the wild, the starlet sea anemone is considered a "Vulnerable species" by the IUCN, which means it needs protection.
What Does It Look Like?
The starlet sea anemone has a body that can stretch from about 2 to 6 centimeters long. That's about the length of your thumb! The bottom part of its body is a bit wider, like a bulb. Its main body part is called the scapus, and the part just below its tentacles is called the capitulum.
Its body is often covered in a thin layer of sticky mucus. This mucus helps sand and mud stick to it. At the very top, it has a mouth surrounded by two rings of long, thin tentacles. Most starlet sea anemones have 14 tentacles, but some can have up to 20. The outer tentacles are usually longer than the inner ones. This anemone is mostly clear and doesn't have much color. But it often has cool white patterns on its body and white stripes on its tentacles.
Where Does It Live?
You can find the starlet sea anemone along the coasts of North America. On the east coast, it lives from Nova Scotia in Canada all the way down to Louisiana. On the west coast, it's found from Washington state down to California. It also lives in three places in the United Kingdom: two spots in East Anglia and one on the Isle of Wight.
This sea anemone loves brackish water. This means the water is a mix of fresh and salty water, like in ponds, lagoons, and ditches in salt marshes. It prefers places where the water doesn't move too fast. You usually won't find it more than one meter (about three feet) below the surface. It can handle a wide range of saltiness in the water. It seems to grow best when the water is just a little bit salty. It usually buries itself in fine mud or sand, with only its tentacles showing on the surface. When it's not eating, it pulls its tentacles back into its body.
What Does It Eat?
Sometimes, you can find many starlet sea anemones living close together. There can be as many as 2,700 in just one square meter! In England, other animals that live with it include the lagoon cockle and different types of worms, isopods, and amphipods. Plants in its home include foxtail stonewort, green algae, and ditch grass. In North America, it lives among saltmarsh grasses and green algae.
The starlet sea anemone eats tiny creatures. Its diet includes small crustaceans like ostracods and copepods. It also eats small mollusks, insect larvae, nematodes, and other small worms. It can even eat egg masses from other animals. The only animal known to hunt and eat the starlet sea anemone is a type of shrimp called the grass shrimp (Palaemonetes pugio).
Life Cycle
On the east coast of the United States, starlet sea anemones mostly reproduce sexually. They become old enough to reproduce when they are about three to four months old and at least 2 centimeters long. A female anemone can lay up to two thousand eggs in a jelly-like clump. Tiny, round larvae, called planula larvae, hatch from these eggs after about two days. These larvae float in the water for about a week. Then, they settle down on the mud and change into young sea anemones.
In southern England, all the starlet sea anemones seem to be female. They reproduce by budding. This means a new anemone grows out of the side of an existing one. It's common to see anemones with two crowns of tentacles in this area. These then split into two separate sea anemones. On the west coast of the United States and in Nova Scotia, all the anemones are male. In these places, they likely reproduce without needing a partner, which is called asexual reproduction.
Research
Scientists love to study the starlet sea anemone. It's one of the simplest animals that has its cells organized into different tissues. It has special cells like skin cells, nerve cells, and muscle cells. It also has stem cells, which can turn into different types of cells.
Nematostella vectensis is used as a "model organism" in labs. This means scientists study it to understand bigger ideas about how life works. They use it to learn about evolution, genomics (how genes work), how animals reproduce, how they develop, and how they interact with their environment. It's easy to keep in the lab, even far from the ocean. Scientists have even figured out how to make them produce many embryos every day.
Scientists have also mapped out its entire set of genes, called its genome. They found that its genes are surprisingly similar to those of humans and other vertebrates (animals with backbones). This is interesting because it's very different from the genes of fruit flies and worms, which have lost many genes over time. This suggests that the common ancestor of sea anemones and humans had a very complex set of genes.
Researchers have even discovered that some genes involved in forming the head in more complex animals are also found in Nematostella vectensis. In the larval stage, the anemone swims with its main sense organ at the front. When it changes into an adult, this front part becomes the bottom of its body. The "head" gene helps develop this lower end, not the tentacles.
- Uhlinger, K. R. (1997). Sexual reproduction and early development in the estuarine sea anemone, Nematostella vectensis Stephenson, 1935. Thesis. University of California, Davis.
