Urocordados, Cefalocordados e Agnatos - Cordados. Aula 27 - Módulo VI: Zoologia | Prof. Gui

Summary

This educational script discusses chordates, focusing on simpler representatives like Uruguaios and Agnathans, also known as Psco and Luiz Tomados. The narrator, Professor Guilherme, explains the characteristics of chordates, such as having a notochord and a dorsal nerve cord. He details their life stages, from larvae with a notochord in their tails to adults without it. The script also covers their physiology, including feeding, respiration, and circulation systems. Additionally, it touches on their reproduction, which is hermaphroditic with external fertilization. The lecture concludes with a motivational message emphasizing hard work over inspiration for success.

Takeaways

• 🐟 The script discusses chordates, specifically focusing on the simplest representatives: uruguayans, sef cordadas, and agnatus, also known as psico luiz tomados.
• 🧬 The speaker, Professor Guilherme, emphasizes the importance of recalling the division from a previous lesson to understand chordates.
• 🦴 The term 'acordado' refers to animals with a cranium, while 'ciclo tomado' refers to those without, highlighting the distinction between them.
• 🔍 The script explains that chordates have a nerve cord, which is exclusively in the tail during the larval stage and not present in the adult stage.
• 🌊 The respiratory and circulatory systems of these animals are described, including how they intake and expel water through siphons and have a dorsal nerve cord.
• 🐚 It mentions that these animals have a protective covering called a tunic, made of a substance called tunisina, which was historically the reason they were called 'pubicados'.
• 🍽️ The script describes their feeding mechanism as filter feeders, using a structure called a gill to trap particles and an stomach for digestion.
• 🔄 The circulation in these animals is described as partially open, with blood being pumped in a unique manner by their heart.
• 🌱 The script touches on the reproduction of these animals, noting they are hermaphroditic and undergo external fertilization.
• 📚 The importance of studying and the message that success comes from hard work and dedication, not just inspiration, is emphasized at the end of the script.

Q & A

What is the main difference between chordates and invertebrates?

Chordates are characterized by having a notochord, a dorsal nerve cord, and pharyngeal slits at some point in their life cycle, while invertebrates lack these features.

What are the two main groups of chordates mentioned in the script?

The two main groups of chordates mentioned are the 'Uruguaios' (Uruguayans) and the 'É falou acordados' (those who have spoken).

What is the significance of the notochord in the life cycle of chordates?

The notochord is significant as it is present in the larval stage of chordates but is absent in the adult form. This indicates a metamorphosis from a free-swimming larva to a non-swimming adult.

How do chordates obtain their food?

Chordates obtain their food by filtering it through a structure called the 'faringe', which is filled with cilia that help in capturing food particles.

What is the role of the dorsal nerve cord in chordates?

The dorsal nerve cord in chordates runs along the length of the body and forms a brain-like mass at the front, which is the central nervous system.

What is the function of the siphons in chordates?

The siphons in chordates serve as an inhalant siphon for water intake and an exhalant siphon for water expulsion, which is crucial for their respiration and feeding.

What is the tunica in chordates?

The tunica is an external body covering made of a polysaccharide similar to cellulose called 'tunicine', which provides a protective layer for the animal.

How is the blood circulation in chordates described?

The blood circulation in chordates is described as partially open, with blood flowing through structures called 'sinusoids' that are not true blood vessels.

What is unique about the heart's function in chordates?

The heart in chordates has the unique ability to pump blood both upwards towards the front for gas exchange and downwards for internal organ oxygenation.

What is the reproductive strategy of chordates?

Chordates are hermaphroditic, meaning they have both male and female reproductive organs. They release gametes into the water, leading to cross-fertilization and avoiding self-fertilization.

What is the difference between 'Céfalo acordados' and 'Juros acordados'?

Céfalo acordados have a notochord that extends from the cephalic region to the tail, while Juros acordados have a notochord only in the larval stage, which is located in the tail.