Question

Как изменялось строение хордовых? (Все системы)

Answer 1

К типу Хордовые относятся животные, имеющие внутренний осевой скелет – хорду или позвоночный столб. Хордовые животные достигли в процессе эволюции наибольшего, по сравнению с остальными типами, уровня организации и расцвета. Они живут во всех областях земного шара и занимают все среды обитания.

Хордовые– это двусторонне-симметричные животные, имеющие вторичную полость тела и вторичный рот.

У хордовых наблюдается общий план строения и расположения внутренних органов:

– нервная трубка расположена над осевым скелетом;

– под ней расположена хорда;

– под хордой находится пищеварительный тракт;

– под пищеварительным трактом – сердце.

Answer 2

Evolution of Chordate Structure

Chordates are a diverse group of animals that include vertebrates (animals with a backbone) and some invertebrates. The structure of chordates has evolved over millions of years, leading to the development of various systems within their bodies. Here is a brief overview of how chordate structure has changed over time:

1. Protochordates: Protochordates are considered the most primitive chordates. They include animals such as tunicates and lancelets. Protochordates have a simple body plan with a notochord, a hollow nerve cord, and pharyngeal slits. These structures serve as the basis for the more complex systems found in later chordates.

2. Early Vertebrates: Early vertebrates, such as jawless fish like lampreys and hagfish, evolved from protochordates. They developed a more advanced skeletal system, including the development of a true vertebral column. This allowed for greater support and protection of the spinal cord.

3. Jawed Vertebrates: Jawed vertebrates, including cartilaginous fish (sharks and rays) and bony fish (such as salmon and trout), evolved from early vertebrates. The development of jaws allowed for more efficient feeding and predation. Additionally, the evolution of paired fins and gills further enhanced their ability to move and respire in aquatic environments.

4. Tetrapods: Tetrapods are vertebrates with four limbs. They include amphibians, reptiles, birds, and mammals. The evolution of limbs allowed tetrapods to move onto land and adapt to terrestrial environments. The development of lungs and other respiratory adaptations facilitated respiration in air. Tetrapods also developed more complex sensory organs and reproductive systems.

5. Mammals: Mammals are a group of tetrapods that have evolved various adaptations for survival. These include the development of mammary glands for milk production, hair or fur for insulation, and specialized teeth for different diets. Mammals also possess a highly developed brain and nervous system, allowing for complex behaviors and cognitive abilities.

It's important to note that the evolution of chordate structure is a complex process that occurred over millions of years, with many intermediate forms and variations. The examples mentioned above are just a few highlights of the major changes that have taken place in chordate structure.

I hope this provides a detailed overview of how chordate structure has changed over time. If you have any more specific questions or need further clarification, feel free to ask!