Problem 142 - Objective Biology for NEET

Question

Sea urchin belongs to the class phylum (a) Echinodermata (b) Hemichordata (c) Ctenophora (d) Mollusca

Step-by-Step Solution

Answer

The correct answer is (a) Echinodermata.

Step 1: Understanding Taxonomy

Firstly, one should understand the taxonomy of animals. Taxonomy is the practice of classifying organisms into categories based on their characteristics. The primary ranks in modern use are domain, kingdom, phylum, class, order, family, genus, and species.

Step 2: Classifying the Sea Urchin

The next step is to classify the sea urchin. Sea urchins are small, spiny sea creatures that are typically found in warm waters. They're known for their spherical shape and long, sharp spines that they use for protection.

Step 3: Identifying the Correct Phylum

The final step is to identify the correct phylum that the sea urchin belongs to from the choices given. In this case, the sea urchin falls under the phylum Echinodermata, which includes other marine animals such as starfish and sand dollars.

Key Concepts

Echinodermata

Sea urchins are fascinating creatures that belong to the phylum Echinodermata. This phylum is characterized by marine animals having radial symmetry and a water vascular system. These animals usually have five-pointed symmetry, regardless of their distinctive shapes. Most of them have a hard, calcareous skeleton beneath their outer skin, which provides support and protection.
Echinoderms are known for their ability to regenerate lost body parts, and some, like starfish, are able to grow back lost arms. Their bodies typically consist of a central disk with rays (arms) extending outwards. This unique symmetry sets them apart from many other animal groups and plays an essential role in the phylum's classification.

• Sea Urchins
• Starfish
• Sea Cucumbers
• Sand Dollars

These creatures thrive in a variety of marine environments, from shallow coastal areas to the deep sea, showcasing the adaptability and diversity of the Echinodermata phylum.

Phylum Classification

Phylum classification is a critical step in understanding the vast diversity of life on earth. It is a method used by scientists to group organisms that share significant characteristics. The hierarchical structure of classification starts from broad categories and narrows down to specific ones, allowing us to understand how organisms are related to each other.
Here's the breakdown of the taxonomy ranks:

• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

When classifying sea urchins, we place them under the kingdom Animalia, the phylum Echinodermata, and further into specific classes based on distinct characteristics.
The classification helps scientists communicate about species, understand evolutionary relationships, and predict characteristics shared by grouped organisms. It's a vital tool in biology that not only organizes animals but also provides insights into their evolutionary history.

Marine Animals

Marine animals are spectacular as they live in the ocean, which covers most of the Earth's surface. These creatures have adapted to the diverse and sometimes challenging environments found underwater. They range from the smallest microbes to the largest whales.
Echinoderms, like sea urchins, are among these marine animals and display unique adaptations such as tube feet for movement and feeding. Other specified examples of marine animal groups include:

• Fish - Including jawless, cartilaginous, and bony species
• Crustaceans - Such as crabs and lobsters
• Corals - Which form coral reefs, important marine habitats
• Mollusks - Including snails, clams, and squids

Marine ecosystems are rich in biodiversity and play essential roles in global processes such as carbon cycling and climate regulation. Understanding these animals enhances our comprehension of broader ecological patterns and the significance of maintaining healthy marine environments for the future of our planet.