What are Protochordates? | Biology | Sub Phylum of Chordata | Animal Kingdom : Protochordata

Summary

The video explains the characteristics and classification of chordates, animals belonging to the phylum Chordata. It details the key features of chordates, including the notochord, dorsal nerve cord, and post-anal tail. The video covers two main groups: vertebrates and protochordates. It then dives deeper into the three subgroups of protochordates—hemichordates, eurochordates, and cephalochordates—highlighting their unique characteristics. The video also answers sample questions to test viewers' understanding of the topic, making it both educational and engaging for learners.

Takeaways

• 😀 Chordates are animals belonging to the phylum Chordata and possess a notochord, hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail at some stage of their life.
• 😀 Chordates are classified into two subphyla: vertebrates and protochordates.
• 😀 Vertebrates only have a notochord during their embryonic stage, which is replaced by a vertebral column in adults.
• 😀 Vertebrates have a ventral muscular heart, kidneys for excretion and osmoregulation, and can have two, three, or four chambers in their hearts.
• 😀 Protochordates retain the notochord throughout their life and have a ventral heart, perforated gill slits, and a post-anal tail.
• 😀 Protochordates are divided into three groups: Hemichordata, Urochordata, and Cephalochordata.
• 😀 Hemichordates are marine organisms with an organ-level body organization, a notochord at the anterior end, and gill respiration.
• 😀 Urochordates are exclusively marine, have a notochord only in the larval tail, and develop a tunic in their adult stage.
• 😀 Cephalochordates have a notochord extending from head to tail, gill slits for respiration, and a well-developed circulatory system.
• 😀 In chordates, the post-anal tail, which provides balance and protection, is a distinguishing feature absent in non-chordates.

Q & A

What is the defining characteristic of animals in the phylum Chordata?

Animals in the phylum Chordata are defined by possessing a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail at some stage of their life cycle.

What are the two subphyla of Chordata?

The two subphyla of Chordata are Vertebrata and Protochordata.

What distinguishes vertebrates from protochordates in terms of the notochord?

In vertebrates, the notochord is only present during the embryonic stage and is replaced by a vertebral column in adults. In protochordates, the notochord is present throughout their life.

What are the major differences between vertebrates and protochordates?

Vertebrates have a vertebral column, a ventral muscular heart, and kidneys for excretion and osmoregulation. Protochordates, on the other hand, retain their notochord throughout life and lack these structures.

What is the key feature of Hemichordates?

Hemichordates are marine animals where the notochord is present only at the anterior end of the body, and the body is divided into a proboscis, collar, and trunk. They breathe through gills.

What distinguishes Eurochordates from other protochordates?

Eurochordates are marine, and the notochord is present only in the larval tail. In adults, they develop cuticular tunics.

Where are Cephalochordates typically found, and what is their defining characteristic?

Cephalochordates are typically buried in soil, and their notochord extends from the head to the tail region. They have paired gill slits for respiration.

What is the function of the post-anal tail in chordates?

The post-anal tail in chordates helps with balance, and in many species, it provides protection to the genital and anal regions.

What type of heart do vertebrates typically have?

Vertebrates generally have a ventral muscular heart, which can be two, three, or four-chambered.

Which group of animals has a notochord only during the larval stage?

Eurochordates have a notochord only during their larval stage. The notochord is absent in the adult stage.