Trochophore larva

Definition

A trochophore larva is a free-swimming, ciliated larval stage commonly found in the development of certain marine invertebrates, such as molluscs and annelids. This larval form is characterized by a distinct body shape, often oval or spherical, and bands of cilia that enable locomotion and feeding. Trochophore larvae are crucial for the dispersal and life cycle of these organisms, linking them to both their adult forms and their ecological roles in marine environments.

5 Must Know Facts For Your Next Test

1. Trochophore larvae are typically part of the life cycle of lophotrochozoans like molluscs and annelids, allowing them to disperse in marine environments.
2. This larval form features a unique band of cilia around its equator, which helps with movement and feeding on phytoplankton or other small particles.
3. Trochophore larvae can develop into different forms depending on species; for example, some may transform into veliger larvae in molluscs.
4. The presence of trochophore larvae highlights the evolutionary relationships between diverse groups within the Lophotrochozoa superphylum.
5. The trochophore stage is often followed by metamorphosis, leading to the adult form that exhibits distinct morphological adaptations for life on the ocean floor.

Review Questions

• How do trochophore larvae contribute to the life cycle of marine invertebrates and their ecological roles?
  • Trochophore larvae play a vital role in the life cycle of marine invertebrates, particularly molluscs and annelids, by facilitating dispersal across vast oceanic distances. This free-swimming larval stage allows organisms to spread their populations over a wide area, which is crucial for maintaining genetic diversity. Additionally, trochophore larvae contribute to their ecological roles as they feed on phytoplankton and help transfer energy through the marine food web.
• Discuss the significance of cilia in the structure and function of trochophore larvae.
  • Cilia are critical to the structure and function of trochophore larvae as they provide both locomotion and feeding mechanisms. The bands of cilia encircling the body allow these larvae to swim effectively through the water column, avoiding predators while searching for food. Additionally, cilia help capture small particles from the surrounding water, playing an essential role in nutrient acquisition during this early life stage.
• Evaluate the evolutionary importance of trochophore larvae within the context of Lophotrochozoa and its implications for understanding marine biodiversity.
  • Trochophore larvae represent a significant evolutionary adaptation within Lophotrochozoa, showcasing how different groups have evolved similar developmental strategies despite diverging into various forms. Their presence across multiple phyla highlights convergent evolution and indicates shared ancestry among these diverse organisms. Understanding trochophore larvae's role can illuminate patterns of marine biodiversity, providing insight into how environmental factors shape developmental processes and influence species distributions in ocean ecosystems.

Related terms

Lophophore: A specialized feeding structure found in some lophotrochozoans, characterized by a crown of ciliated tentacles used for capturing food particles from the water.

Metamorphosis:

The process by which a larva undergoes transformation into its adult form, involving significant changes in morphology and physiology.

Spiral Cleavage: A type of embryonic development seen in many lophotrochozoans, where the cells divide in a spiral arrangement, influencing the future body plan of the organism.