Question

Сравните типы червей плоские и кольчатые

Answer 1

 Плоские черви (низшие турбеллярии): 
1. около 2500 видов
2. тело плоское, листовидное, лентовидное
3. имеют спинную и брюшную сторону
4. впервые - наличие кожно-мускульного мешка
5. впервые - появляются ткани и органы
6. системы органов: нервная, пищеварительная, выделительная, половая
7. промежутки между органами заполнены соединительной тканью - паренхимой
8. двусторонняя (билатеральная) симметрия
9. впервые - трехслойные животные; появляется третий слой - мезодерма (между эктодермой и энтодермой)

Кольчатые черви (кольчецы):
1. около 9000 видов
2. длинное тело, состоящее из колец (сегментов)
3. имеется внутренняя сегментация
4. трехслойные
5. впервые - вторичная полость тела - целом (выстлана покровными клетками)
6. два слоя мышц (кольцевые и продольные)
7. впервые - появляются параподии (зачатки)
8. впервые - замкнутая кровеносная система
9. усложнение пищеварительной системы - появляется желудок
10. впервые - жабры (у морских)
11. органы выделения - метанефридии
12. впервые - нервная система - цепочного типа
13. раздельнополые и гермафродиты (развитие прямое или с превращением)

Answer 2

Types of Worms: Flatworms and Segmented Worms

When comparing the types of worms, we can focus on two main categories: flatworms and segmented worms. Let's explore each type in more detail:

Flatworms: Flatworms, also known as Platyhelminthes, are a group of worms characterized by their flattened bodies. They belong to the phylum Platyhelminthes and include various species such as tapeworms, planarians, and flukes. Here are some key points about flatworms:

- Body Structure: Flatworms have a dorsoventrally flattened body, which means they are flattened from top to bottom. This body shape allows them to live in various habitats, including freshwater, marine environments, and even as parasites in the bodies of other animals. - Digestive System: Flatworms have a simple digestive system with a single opening that serves as both the mouth and anus. This means that food enters and waste exits through the same opening. - Nervous System: Flatworms have a relatively simple nervous system consisting of a network of nerve cells called a nerve net. This nerve net allows them to detect and respond to their environment. - Reproduction: Flatworms can reproduce both sexually and asexually. Some species are hermaphroditic, meaning they have both male and female reproductive organs, while others have separate sexes.

Segmented Worms: Segmented worms, also known as Annelids, are a diverse group of worms characterized by their segmented bodies. They belong to the phylum Annelida and include various species such as earthworms, leeches, and polychaetes. Here are some key points about segmented worms:

- Body Structure: Segmented worms have bodies divided into distinct segments or rings. Each segment contains specific organs and structures, such as muscles, nerves, and reproductive organs. This segmented body plan allows for greater flexibility and specialization. - Digestive System: Segmented worms have a complete digestive system with a separate mouth and anus. Food enters through the mouth and passes through a series of specialized structures, such as the pharynx and crop, for digestion and absorption. - Nervous System: Segmented worms have a more complex nervous system compared to flatworms. They have a ventral nerve cord that runs along the length of their body and ganglia (clusters of nerve cells) in each segment. This allows for better coordination and control of their movements. - Reproduction: Segmented worms can reproduce both sexually and asexually. Some species are hermaphroditic, while others have separate sexes. They often engage in complex mating behaviors and produce eggs or cocoons for reproduction.

In summary, flatworms and segmented worms are two distinct types of worms with different body structures, digestive systems, nervous systems, and reproductive strategies. Flatworms have flattened bodies and a simple digestive system, while segmented worms have segmented bodies and a more complex digestive system. Both types of worms play important roles in various ecosystems and have diverse adaptations for survival and reproduction.