Invertebrate Zoology: Introduction to the Gnathifera LN11

These flashcards cover key vocabulary and concepts from the lecture on the Gnathifera, helping students understand important definitions and characteristics of this clade.

Gnathifera

A clade within The Spiralia made up of four different phyla with shared morphological characteristics.

Phyla of Gnathifera

Includes Chaetognatha, Gnathostomulida, and Rotifera.

Homologous structures

Anatomical features in different species that share a common ancestry, often adapted for similar functions like prey grasping.

Bilateral symmetry

A body plan in which the left and right sides of the organism are mirror images.

Triploblastic

Organisms that develop from three embryonic layers: ectoderm, mesoderm, and endoderm.

Acoelomate

An organism that lacks a coelom, or body cavity, generally exhibiting solid tissue.

Coelomate

An organism with a true coelom, a fluid-filled body cavity completely surrounded by mesoderm.

Pseudocoelomate

An organism with a body cavity that is not completely lined by mesoderm; typical of Rotifera.

Pharyngeal jaws

Jaws located in the pharynx of certain organisms used for grasping and processing food.

Protonephridia

A network of tubules used for excretion found in some invertebrates, aiding in the regulation of body fluids.

Simultaneous hermaphrodites

Organisms that have both male and female reproductive organs and can perform both reproductive roles.

Mastax

A muscular pharynx that supports pharyngeal jaws, particularly in rotifers.

Cloaca

A shared opening in certain animals for expelling waste and reproductive materials.

Pedal glands

Glands in rotifers that secrete a sticky substance to help with attachment to surfaces.

External spines

Structures used for grasping prey, found in Chaetognatha.

Gas exchange via diffusion

The process by which gases are exchanged through the cell membranes without specialized systems.

Direct development

Developmental process where organisms mature directly into adults without a larval stage.

Nervous system in Gnathifera

Consists of ventral and dorsal ganglia acting as control centers; includes eye spots for light detection.