Crustáceos (Artrópodes: Parte 2) - Aula 21 - Módulo VI: Zoologia | Prof. Guilherme

Summary

In this biology lesson, Professor Guilherme introduces crustaceans, focusing on their anatomy, physiology, and ecological significance. The lecture covers key features such as the two-part body structure (cephalothorax and abdomen), ten pairs of legs, two pairs of antennae, and the specialized eyes and respiratory systems. The crustaceans' role in aquatic food chains, particularly krill as a food source for marine mammals like whales, is also discussed. The lesson also touches on reproduction, excretion, and their importance in marine ecosystems. Through detailed explanations, students gain a deeper understanding of crustaceans' biological and ecological roles.

Takeaways

• 😀 Crustaceans are a diverse group of arthropods, including lobsters, crabs, shrimps, and even land-dwelling pill bugs (Tatuzinho).
• 😀 Crustaceans have two main body parts: the cephalothorax (fused head and thorax) and the abdomen.
• 😀 Crustaceans possess ten pairs of legs—five pairs of thoracic legs and five pairs of abdominal legs, each with specific functions.
• 😀 The thoracic legs are often used for movement, while the abdominal legs, or pleopods, help with swimming and reproductive purposes, especially in females.
• 😀 Many crustaceans have pincers (chelae) that help in defense, feeding, and manipulation of objects, such as mollusk shells.
• 😀 Crustaceans are unique in having two pairs of antennae, one shorter and one longer, which serve as sensory organs for environmental awareness.
• 😀 Their eyes are compound, made of many smaller units, and are movable for better positioning and focus.
• 😀 Crustaceans have an open circulatory system with hemolymph (similar to blood) containing copper-based oxygen transport proteins, which makes their blood blue.
• 😀 The excretory system in crustaceans includes green glands located near their antennae, responsible for excreting ammonia, the primary waste product.
• 😀 Crustaceans have a specialized structure, the statocyst, that helps them sense their orientation and maintain balance in the water.
• 😀 Crustaceans generally have separate sexes, and reproduction involves external fertilization. The fertilized eggs develop into larvae before maturing into adults.

Q & A

What are the main groups of crustaceans discussed in the lesson?

The main groups of crustaceans discussed include lobsters, crabs, shrimps, and pill bugs (tatuzinhos).

How is the body of a crustacean structured?

A crustacean's body is divided into two main parts: the thorax and the abdomen.

What is the function of the five pairs of thoracic legs in crustaceans?

The five pairs of thoracic legs are primarily used for locomotion, and some crustaceans modify these legs for feeding or manipulation of objects.

Why do some crustaceans have pincers on their front legs?

Pincers, or chelae, are used for defense and for manipulating food, such as tearing apart prey or handling objects, like shells.

What is the role of the antennae in crustaceans?

The antennae in crustaceans serve as sensory organs, helping them detect vibrations and chemical substances in the water, allowing them to navigate their environment.

What is unique about the eyes of crustaceans compared to other arthropods?

Crustaceans have compound eyes, which are capable of moving to adjust focus and provide a broader field of vision. This movement distinguishes their eyes from those of other arthropods.

How do crustaceans maintain balance and detect their position in the water?

Crustaceans use a structure called a statocyst, which contains sensory cells and tiny stones called statoliths that help them sense their orientation and balance in the water.

What type of circulatory system do crustaceans have?

Crustaceans have an open circulatory system, where blood, or hemolymph, flows freely in the body cavity rather than through a series of closed blood vessels.

How do crustaceans excrete waste?

Crustaceans excrete waste through specialized glands called green glands, located near the base of the antennae, where they expel ammonia, the primary waste product.

What is the significance of krill in aquatic food chains?

Krill are tiny crustaceans that serve as a critical food source for large marine animals, including blue whales. They feed on phytoplankton and contribute significantly to aquatic food webs.