Urochordata & Cephalochordata

Summary

Proto chordates, an informal group including subphyla Urochordata and Cephalochordata, are closely related to vertebrates despite being invertebrates. Urochordata, known for sessile tunicates and the predatory Didemnum, are filter feeders with some forming massive colonies. Cephalochordata, represented by amphioxus, have fish-like bodies. Both reproduce asexually and sexually, avoiding self-fertilization for genetic diversity. Tunicates, like the edible sea pineapple, feature in Asian cuisine, while Didemnum is invasive in the US, impacting ecosystems.

Takeaways

• 🐟 Protochordates are an informal group closely related to vertebrates, despite being invertebrates.
• 🌊 Subphylum Urochordata includes tunicates, which are sessile filter feeders, while Cephalochordata includes the amphioxus, which have fish-like bodies.
• 🌿 Tunicates can reproduce both sexually and asexually, with the latter often occurring through budding.
• 🔍 There is a predatory tunicate species that feeds on small marine animals using a hood-like mouth.
• 🌐 Colonial tunicates, known as pyrosomas, can form massive structures up to 60 feet long.
• ⚠️ Invasive tunicate species have impacted ecosystems in the United States by suffocating native species with dense coverings on the ocean floor.
• 🍣 The sea pineapple, an edible tunicate, is part of Korean and Japanese cuisine and is known for its combination of four tastes.
• 🥗 Pirarucu, or 'pure' in Spanish, is a type of tunicate used in Chilean and Peruvian cuisine, noted for its slightly bitter, soapy flavor.
• 🍤 Lance lips, often mistaken for small fish, are fried in Southeast Asian cuisine.
• 🔬 All protochordates exhibit the core characteristics of the phylum Chordata at some life stage, with amphioxus being the only ones to show all traits as adults.
• 🧬 Both urochordates and cephalochordates are considered close relatives to vertebrates, providing insights into the common ancestry of the cranium.

Q & A

What is the significance of the term 'proto chordates'?

Proto chordates is an informal group that includes the subphyla Echinodermata and Cephalochordata, suggesting their close relation to vertebrates despite being invertebrates.

What are the two subphyla included in the proto chordates group?

The two subphyla included in the proto chordates group are Echinodermata and Cephalochordata.

What types of organisms are part of the subphylum Echinodermata?

The subphylum Echinodermata includes organisms such as sea squirts, tunicates, and their larvae.

What is the common name for the subphylum Cephalochordata?

The subphylum Cephalochordata is commonly known as amphioxus or lancelets.

How do tunicates differ from amphioxus in terms of habitat and behavior?

Tunicates are sessile, meaning they are attached to a substrate, while amphioxus have fish-like bodies that they use to burrow in the sand.

What is the primary feeding method of most tunicates?

Most tunicates are filter feeders, collecting small organic particles from the surrounding water.

What is unique about the predatory tunicate species?

The predatory tunicate species is unique as it feeds on small marine animals with a mouth like a hood.

How do colonies of tunicates known as Pyrosoma ohms form and what is their impact on the environment?

Colonies of Pyrosoma ohms form by budding, a form of asexual reproduction, and can create massive structures up to 60 feet long, which can suffocate native species by creating a dense covering along the ocean floor and surrounding surfaces.

What is the reproductive strategy of tunicates?

Tunicates can reproduce both sexually and asexually, with the latter typically occurring through budding and the former involving the release of sperm and eggs into the surrounding water for external fertilization.

Why do tunicates generally avoid self-fertilization?

Tunicates generally avoid self-fertilization to promote genetic variability, which is important for the health and adaptability of the species.

What is the culinary significance of the sea pineapple and how is it typically prepared?

The sea pineapple, an edible tunicate, is part of the culinary palate in Korea and Japan, usually served raw, boiled, or pickled, and is known for combining the four tastes of sweetness, saltiness, acidity, and sourness.

How is the tunicate known as 'pirarucu' used in Chilean and Peruvian cuisine?

The tunicate known as 'pirarucu' or 'piye' in Spanish is used in the cuisine of Chile and Peru, where it can be eaten raw or cooked and is said to have a slightly bitter, soapy flavor.

What is the common mistake made when referring to 'lance lips' in Southeast Asian cuisine?

The common mistake made when referring to 'lance lips' in Southeast Asian cuisine is that they are often wrongly called small fish, despite being a type of tunicate.

Why are the proto chordates considered important in the study of vertebrate evolution?

Proto chordates are considered important in the study of vertebrate evolution because they exhibit the four core chordate characteristics at some stage in their life, providing clues to the common ancestry of the craniates.