Model Answer
0 min readIntroduction
Peripatus, often called the velvet worm, represents a fascinating group of invertebrates occupying a unique position in the animal kingdom. Discovered in the 19th century, it exhibits characteristics intermediate between annelids and arthropods, earning it the title of a ‘living fossil’. These elongated, cylindrical creatures are found in humid forest floors of tropical and subtropical regions, primarily in the Southern Hemisphere. Understanding Peripatus provides valuable insights into the evolutionary relationships between these two major phyla.
Morphology and Habitat
Peripatus typically measures 5-20 cm in length and possesses a soft, segmented body covered in numerous papillae, giving it a velvety texture. They inhabit damp leaf litter, crevices in bark, and under stones in tropical rainforests of South America, Africa, and Australasia.
Locomotion and Feeding
Locomotion is achieved through lobopods – unjointed, stubby legs with claws. Peripatus are predatory, feeding on small invertebrates like insects and worms. They capture prey by squirting a sticky slime from oral papillae.
Reproduction and Evolutionary Significance
Reproduction can be both sexual and parthenogenetic. They exhibit unique reproductive strategies, including internal fertilization and the development of embryos within the mother’s oviduct.
Key Characteristics – Connecting Link
- Tracheal System: Similar to arthropods, but with simple, unbranched tracheae.
- Segmented Body: Resembles annelids.
- Claws: Present on lobopods, aiding in locomotion.
- Slime Glands: Unique predatory adaptation.
Peripatus is considered a crucial ‘connecting link’ because it displays a mosaic of features found in both annelids and arthropods, providing evidence for their common ancestry. Its onychophoran characteristics are primitive traits that shed light on the evolution of arthropod appendages and respiratory systems.
Conclusion
In conclusion, Peripatus stands as a remarkable example of evolutionary conservation, retaining ancestral traits that illuminate the phylogenetic relationships between annelids and arthropods. Its unique morphology, predatory behavior, and reproductive strategies make it a subject of continued scientific interest, offering valuable insights into the evolutionary history of invertebrates and the development of key anatomical features.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.