Consider the following statements regarding Sea Urchins: They are mari...
Explanation:
The correct answer is option C, which means both statements 1 and 2 are correct.
Statement 1: They are marine invertebrates found on oceans floors worldwide.
This statement is correct. Sea urchins are marine invertebrates that belong to the phylum Echinodermata. They are found in oceans all around the world, from shallow waters to deep-sea habitats. They are commonly found on the ocean floors, where they graze on algae and other organic materials.
Statement 2: They include marine creatures like starfish and sea cucumbers.
This statement is also correct. Sea urchins are part of a larger group of marine creatures called echinoderms. Other echinoderms include starfish (also known as sea stars), sea cucumbers, sea lilies, and brittle stars. These animals share similar characteristics, such as a radial symmetry and a spiny or bumpy skin.
Additional Information:
Sea urchins are characterized by their round or spherical shape and their spiny exterior. They have a hard exoskeleton called a test, which is covered in movable spines. These spines serve as a defense mechanism against predators and also help in locomotion. Sea urchins have a mouth located on the underside of their body, surrounded by five tooth-like structures called Aristotle's lantern. They use these teeth to scrape algae and other food sources from rocks and other surfaces.
Sea urchins play an important ecological role in marine ecosystems. They help to control algae growth by grazing on it, and they also serve as a food source for many predators, such as sea otters, lobsters, and birds. In some areas, sea urchins can become overpopulated and cause damage to coral reefs or kelp forests by overgrazing.
In conclusion, sea urchins are marine invertebrates found on ocean floors worldwide. They are part of the larger group of echinoderms, which includes animals like starfish and sea cucumbers. Sea urchins are important players in marine ecosystems and have distinct physical characteristics that enable them to survive and thrive in their environments.
Consider the following statements regarding Sea Urchins: They are mari...
The Red Sea's spectacular coral reefs face a new threat, marine biologists warn—the mass death of sea urchins that may be caused by a mystery disease.
About Sea Urchins:
- Sea urchins belong to a group of marine invertebrates called echinoderms, which means spiny-skinned animals.
- It includes other well-known marine creatures like starfish and sea cucumbers.
- Sea urchins are characterized by their spherical to somewhat flattened, spiny bodies, and they are found in oceans worldwide, from shallow coastal waters to deep-sea environments.
- They live on the ocean floor, usually on hard surfaces, and use tube feet or spines to move about.
- The largest urchin (known from a single specimen) is Sperostoma giganteum of deep waters off Japan.
- Features:
- They have a globular body and a radial arrangement of organs, shown by five bands of pores running from mouth to anus over the test (internal skeleton).
- The pores accommodate tube feet, which are slender, extensible, and often sucker-tipped.
- They have a hard exoskeleton, or test, made up of interlocking plates or ossicles, which are often covered with movable spines.
- From nodules on the test arise long, movable spines and pedicellariae (pincerlike organs); these structures may have poison glands.
- Feeding:
- They are herbivorous, primarily feeding on algae and plant material.
- They use their specialized mouthparts, called Aristotle's lantern, to scrape algae and other food sources from rocks or the seafloor.
Hence both statements are correct.
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