Crustaceans

Definition

Crustaceans are a diverse group of marine arthropods characterized by their hard exoskeleton, jointed limbs, and segmented bodies. They play vital roles in marine ecosystems as both predators and prey, contributing significantly to the food web and nutrient cycling within aquatic environments.

5 Must Know Facts For Your Next Test

1. Crustaceans are primarily aquatic and are found in a variety of habitats including oceans, freshwater rivers, and lakes.
2. They undergo a process called molting, where they shed their exoskeleton to grow, which can leave them vulnerable to predators until their new exoskeleton hardens.
3. Crustaceans have a wide range of feeding habits, with some being scavengers, while others are filter feeders or active hunters.
4. Many crustaceans have specialized appendages that are adapted for various functions, such as swimming, walking, or grasping prey.
5. They have complex life cycles that often include larval stages, such as nauplius and zoea, which are different from their adult forms.

Review Questions

• How do the physical characteristics of crustaceans contribute to their survival in marine environments?
  • Crustaceans possess a hard exoskeleton that provides protection against predators and environmental stressors. Their jointed limbs allow for mobility and adaptability in various marine habitats. Additionally, the segmented body structure helps with flexibility and efficient movement through water. These physical traits enable crustaceans to thrive as both hunters and prey in complex marine ecosystems.
• Discuss the ecological roles that crustaceans play in marine ecosystems and how their activities impact other marine organisms.
  • Crustaceans serve crucial ecological roles as both primary consumers and secondary consumers in marine food webs. They contribute to nutrient cycling by breaking down organic matter as scavengers and providing food for larger predators like fish and seabirds. Their activities also influence benthic communities through sediment disturbance during feeding, promoting biodiversity. The presence of crustaceans is essential for maintaining the balance of marine ecosystems.
• Evaluate the impact of environmental changes on crustacean populations and the potential consequences for marine biodiversity.
  • Environmental changes such as climate change, pollution, and habitat destruction can severely impact crustacean populations. For example, rising ocean temperatures may affect their breeding cycles and distribution patterns. Declines in crustacean populations can disrupt food webs, leading to decreased availability of food for larger predators. This imbalance can result in reduced marine biodiversity overall, highlighting the interconnectedness of species within marine ecosystems.

Related terms

Arthropods: A phylum of invertebrate animals that includes insects, arachnids, and crustaceans, known for their jointed limbs and exoskeletons.

Carapace: The hard upper shell of some crustaceans, providing protection to the body and often serving as an attachment point for muscles.

Decapods: A group of crustaceans that have ten limbs, which include familiar species like crabs, lobsters, and shrimp.