Life on Earth
The branch of science that deals with animals and animal life
Zoology
These organisms remain permanently in the plankton
Holoplankton
This fluid dynamics concept facilitates water movement through sponges
Bernoulli's Principle
This specialized cell is unique to cnidarians
Cnidae
These terms indicate the future use of the first opening created during an organisms development
Protostome and Deuterostome
This event created increased competition and opened niches through developments in body structure
The Cambrian Explosion
The formation of germ layers and the resulting embryo
Gastrulation
These cells generate current
Collar cells
This pill-shaped cnidarian form moves through the water using cilia
Planula larvae
This is the primary method that nemerteans use to capture prey
Proboscis
This evolutionary innovation found in a lineage, but not in their ancestors
Apamorphy
These are single-celled or colony forming aquatic eukaryotes
Choanoflagellates
This mid-layer is made of collagen, spicules, and other cell types
Mesohyl
The polyps of this Cnidarian class are exclusively sessile
Anthozoa
This closed, fluid-filled, coelomic space holds the proboscis
Rhynchocoel
This circumglobal sea separating Gondwana and Laurasia
Tethys Sea
When unicellular zygotes transform themselves into multicellular individuals
Ontogeny
This condition creates large, branched, and interconnected chambers in sponges
Leuconoid
This structure (or lack thereof) is the cnidarian attempt at a centralized brain
Diffuse nerve net
Larger nemerteans alternate muscle contractions and expansions to facilitate this form of movement
Peristaltic waves
This group of fossils provides evidence for the advent of many body plans
Burgess Shale Fauna
Development where the yolk is concentrated at one end
Telolecithal
This cell is made of a cytoplasm network and multiple nuclei
Syncytial cell
The free swimming ephyra stage of this class is created during the strobilation process
Scyphozoa
The glandular proboscis epithelium contains these unique stinging cells used for prey capture