Urochordates Characteristics Quiz

Study Notes

Adult tunicates are typically sessile, attaching to various substrates like rocks and shells.
Urochordates can exist as solitary individuals or form colonies through asexual budding, highlighting diverse reproductive strategies.
Tunicates exhibit remarkable regenerative abilities, capable of regrowing lost body parts, enhancing their survival.

The tunic is a defining external covering of urochordates, serving as both protection and structural support.
Primary component tunicin is a cellulose-like carbohydrate, making tunicates unique in producing cellulose among animals.
Tunic contains proteins and glycoproteins that enhance its structure and function.
Living cells within the tunic secrete tunicin and materials for repair and maintenance.
Incorporates minerals, pigments, and foreign materials, adding protection and camouflage.

Serves as a protective barrier against predators and environmental stressors, deterring potential threats.
Provides structural support, maintaining the tunicate's body shape and integrity.
Supports filter feeding by housing incurrent and excurrent siphons, facilitating water flow for feeding.
Resists biofouling, minimizing unwanted accumulations of organisms on its surface.
Living cells assist in regeneration, ensuring functionality after injury.

Represents a significant adaptation for thriving in various marine environments, providing versatile functions.
The presence of tunicin showcases a unique evolutionary development among animals, emphasizing urochordates' distinct capabilities.
Influences ecological interactions, with tunicates incorporating toxic compounds into their tunics for defense.

The pharyngeal basket, heavily perforated with gill slits, serves as the main respiratory structure, drawing water through the incurrent siphon.
Cilia lining the gill slits create currents for effective gas exchange.
Deoxygenated water and waste products exit through the excurrent siphon.

Water with food enters through the incurrent siphon, trapping food particles in mucus within the pharyngeal basket.
The endostyle secretes mucus for food capture, with ciliary action transporting particles to the esophagus.
Food is digested in the stomach with enzymatic breakdown, followed by further digestion and nutrient absorption in the intestine.
Undigested waste is expelled through the anus, leading to the atrial cavity and exiting via the excurrent siphon.

Features an open circulatory system where hemolymph flows through vessels and into body sinuses.
A tubular heart located near the pharyngeal basket periodically reverses blood flow, a unique characteristic among tunicates.
Hemolymph circulates nutrients, gases, and waste products throughout the body, supporting metabolic functions.

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