Ciri Morfologi dan Anatomi Annelida

Summary

This video introduces the basics of analytical morphology through two species: the annelid *Oxydermis pugetensis* and the Nightcrawler *Lumbricus terrestris*. The first species, found in association with California sea stars, is examined for its external and internal anatomy, including its peripodia, tentacles, and supportive structures. The Nightcrawler is used to explore segmented body plans, including reproductive organs, internal digestive systems, and nervous structures. The video highlights how both species offer valuable insights into the study of annelid anatomy, providing a clear view of both external and internal morphological features.

Takeaways

• 😀 Oxidermis is an annelid that can be found in association with a sea star in California and is often used as a model for studying anatomy and morphology.
• 😀 Oxidermis species are small, easy to collect, and sometimes translucent, which makes them great for examining under a microscope.
• 😀 The body plan of Oxidermis consists of repeated, similar units, making it easier to understand despite its seemingly complex appearance.
• 😀 The peripodia of Oxidermis are visible in a side view, and a cross-section reveals two types of cirri and a pair of peripodia with internal structures like keta and acicula.
• 😀 The two parts of the peripodium in Oxidermis are the neuropodium and nodopodium, with distinct types of keta for each.
• 😀 Oxidermis has pre-segmental and post-segmental regions that differ in their anatomy from the segmented body, with the anus and anal series at the posterior end.
• 😀 Oxidermis uses a reversible proboscis for capturing food, and the body cavity stores gametes like eggs.
• 😀 The Nightcrawler (Lumbricus terrestris) is another annelid used to study anatomy, with segments acting as isolated hydrostatic units.
• 😀 Lumbricus terrestris has a noticeable clitellum in reproductively mature individuals, and its segments are clearly defined.
• 😀 In Lumbricus, male gonopores are located on segment 15, and female gonopores are located on segment 14. Both are involved in its hermaphroditic reproduction.
• 😀 The digestive system of Lumbricus includes the pharynx, esophagus, crop, gizzard, and intestine, with specialized organs like calciferous glands and esophageal pouches.
• 😀 The nervous system and circulatory system of Lumbricus are complex and include dorsal blood vessels and muscular lateral vessels, known as hearts, which aid in circulation.

Q & A

What are the two species used in the video to introduce basic analytical morphology?

The two species used are the sea star *Patiria miniata*, which often associates with a species of annelid, and the Nightcrawler, *Lumbricus terrestris*.

Why are *Oxydromus pugetensis* worms a good model for analytical morphology?

They are small, easily collected, and some individuals are translucent, allowing for a clear view of their internal structure.

What body plan features of *Oxydromus pugetensis* make it easier to analyze its anatomy?

The worm has a body plan consisting of repeated, similar units, which simplifies the analysis of its external and internal structures.

What are peripodia, and why are they important in understanding the anatomy of *Oxydromus pugetensis*?

Peripodia are appendages on each segment of the worm. They are crucial for understanding its movement and feeding mechanisms, as they contain tentacles and specialized structures like neuro and nodokiti.

What is the function of the aciculum in *Oxydromus pugetensis*?

The aciculum is an internal supportive structure that provides stability and support to the peripodia.

How do the internal organs of *Oxydromus pugetensis* help in understanding its reproductive system?

The solomonic cavity between the body wall and intestine stores gametes, such as eggs, which are essential for reproduction.

Why is *Lumbricus terrestris* (Nightcrawler) a better model for studying internal anatomy compared to *Oxydromus pugetensis*?

*Lumbricus terrestris* is larger and more opaque, which allows for better dissection and visualization of internal organs, such as the digestive system and nervous system.

What role do segments play in the movement of *Lumbricus terrestris*?

The segments in *Lumbricus terrestris* act as isolated hydrostatic units, which allow for coordinated movement, particularly in the anterior end of the worm.

What is the significance of the clitellum in *Lumbricus terrestris*?

The clitellum is a distinct feature of reproductively mature earthworms. It plays a role in the formation of cocoons for the worms' eggs.

How do *Lumbricus terrestris* worms reproduce, and where do they release their sperm?

*Lumbricus terrestris* are hermaphrodites, meaning they have both male and female reproductive organs. They release sperm from male gonopores located on segment 15 during mating.