8/11/2023 0 Comments Trapdoor spider predators youtube![]() ![]() The Asian Clam is found along sea coasts and estuaries in northern Europe, the Mediterranean and west Africa. For example, the Pacific Razor Clam is found along the Pacific west coast of the United States. The clam is native to many of the world’s oceans and freshwater rivers. Here, you will find interesting videos about different mollusks: They feed by filtering small food particles from water that flows through them. Other ocean living mollusks, like the oyster, attach themselves to rocks or other surfaces, and can’t move. For example, the squid ejects water from a cavity within its body, and the scallop ejects water to move by clamping its shell closed. They propel themselves by ejecting water from their body. Ocean living mollusks move or swim by jet propulsion. Land living mollusks, like the snail, move slowly on a flat sole called a foot. Other mollusks live in water, such as the oyster, mussel, clam, squid and octopus. Some mollusks live on land, such as the snail and slug. Most mollusks have a soft, skin-like organ covered with a hard outside shell. Mollusk fossils are usually well preserved because of their hard shell. Fossils of mollusks have been found in rocks and date back over 500 million years. ![]() Mollusks were among the first inhabitants of the Earth. Pay attention to the anatomy of annelids! d.jpg Some worms are considered parasites, in that they live inside the human body. Other worms, such as the ribbon worm, can grow up to 100 feet in length. Most worms are small, measuring fractions of an inch to several inches long. Commonly known worms include earthworms, roundworms and flatworms. Others have shorter bristles and seem smooth, like the earthworm shown here. One common characteristic of annelids is that they don’t have any limbs. They have very well-developed internal organs. Annelids have existed on Earth for over 120 million years.Īnnelids have bodies that are divided into segments. They can be found almost anywhere in the world. There are about 9,000 species of Annelids known today, including worms and leeches. Now, try to know more about protozoa through this funny activity! Protozoa reproduces by splitting in half. Protozoa take in oxygen and give off carbon dioxide through the cell membrane. ![]() They digest their food in stomach-like compartments called vacuoles. Others surround and engulf their food or have openings to collect food. ![]() Some protozoa absorb food through their cell membrane. Unfortunately, other protozoa are parasites and can be harmful to humans by transmitting disease. Some protozoa are helpful to humans by eating dangerous bacteria. Protozoa play a useful role in the food chain as a source of food for fish and other animals. Flagellates have a body shape looking like a hair.Īlthough we can’t see them, protozoa do a lot for us. However, they do breathe, move and reproduce like multicelled animals. Most protozoa are microscopic in size, and can only be seen under a microscope. Protozoa are simple, single-celled animals. Arthropods include insects, crustaceans and arachnids. The most common invertebrates include the protozoa, annelids, echinoderms, mollusks and arthropods. Others have a hard outer shell, like insects and crustaceans. Many invertebrates have a fluid-filled, hydrostatic skeleton, like the jelly fish or worm. Invertebrates don’t have an internal skeleton made of bone. Of the million or more animal species in the world, more than 98% are invertebrates. ![]()
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