Are Sponges Plants or Animals?
Until the late 1800’s, sponges were considered “animalplants” (zoophytes). more advanced methods of microscopy revealed however that sponges have the cell structure and reproduction of typical animals and cholorophyll pigments found in many species belong to symbiotic (associated) plants (e.g., dinoflagellate zooxanthellae) or photosynthetic bacteria (cyanobacteria) How many species of sponges are there? Approximately 10,000 sponge names are recorded in the literature but not all represent distinct species and some species have been named more than once. Scientists estimate that about 6,000 species names are valid. Because new species are found during most new surveys it has been estimated (from the rate of discovery by area) that nearly 10,000 species of sponges actually exist, circa 4,000 yet to be discovered and described. Are sponges colonies? Each sponge is an integrated organism bound by a simple cell layer (pinacoderm); it should be referred to as an individual. Larvae produced
10. Why don’t fish close their eyes when they sleep? Answers: 1. No. Unlike whales and dolphins, baby seals are born on land and need intensive care from their mothers before they can survive in the ocean. This includes nursing the pups with milk containing about 50 percent fat and protecting them from predators. After a baby seal is weaned, it often sticks around its birth area for a while learning how to swim and forage in the safety of shallow water. 2. A waterspout. 3. Catfish. OK, catfish aren’t marine but they are grown in some of Hawaii’s aquaculture ponds for food. These nocturnal fish have whisker-like barbells around the mouth and venomous spines on their back and side fins. But they don’t have scales. 4. We’re in the middle of it: the Pacific Ocean. 5. It grows a new one. Starfish (sometimes called sea stars) exhibit amazing powers of regeneration. If an arm is eaten or broken off, starfish grow a new one. If at least one-fifth of the central disc is attached to a lost arm,
1. No. Unlike whales and dolphins, baby seals are born on land and need intensive care from their mothers before they can survive in the ocean. This includes nursing the pups with milk containing about 50 percent fat and protecting them from predators. After a baby seal is weaned, it often sticks around its birth area for a while learning how to swim and forage in the safety of shallow water. 2. A waterspout. 3. Catfish. OK, catfish aren’t marine but they are grown in some of Hawaii’s aquaculture ponds for food. These nocturnal fish have whisker-like barbells around the mouth and venomous spines on their back and side fins. But they don’t have scales. 4. We’re in the middle of it: the Pacific Ocean. 5. It grows a new one. Starfish (sometimes called sea stars) exhibit amazing powers of regeneration. If an arm is eaten or broken off, starfish grow a new one. If at least one-fifth of the central disc is attached to a lost arm, it can grow into an entire new starfish. Regeneration is slow.
For many years that question puzzled scientists, but in 1825 a scientist studied sponges under a microscope and saw water enter them through some openings and come out others, looking different. This was evidence that the sponge was an animal which captured tiny plants and animals from the water to use as food, digested them, an
They're animals. Well, actually they're the skeletons of animals. But animals in the ordinary sense. Unlike SpongeBob Squarepants, real sponges lack a head, mouth and internal organs. (Not to mention a tie and pants.) A real sponge consists of little more than myriad water canals that deliver food and oxygen and carry away waste. Although seemingly motionless lumps in life, sponges are really hard workers. A single sponge pumps many gallons of water through its body each day to strain out the tiny, one-celled organisms it eats. Indeed, a sponge has to filter about a ton of water for a single ounce of food. Do mussels have pearls? They do, though saying “The world is my mussel” isn't likely to catch on. A wide range of mollusks is capable of creating pearllike objects, though none generally so fine as those of the pearl oyster (genus Pinctada). Various species of edible mussel form pearls that are the result of infections by a parasitic flatworm called Gymnophallus bursicola. T
