BIO III Porifera - Platyhelminthes Quiz

Radial symmetry

in animal body pattern that has at least two planes of symmetry. Typically, the body is in the form of a cylinder or disk, and the body parts radiate from a central hub.

Bilateral symmetry

An animal body pattern in which one plane of symmetry divides the body into a left side and a right side. Typically, the body is long and narrow, with a distinct head end and tail end.

Ectoderm

The outermost of the three basic cell layers (germ layers) in most animal embryos; gives rise to the outer covering and nervous system.

Endoderm

The innermost of the three basic cell layers (germ layers) in most animal embryos; gives rise to the digestive tract and organs that connect to it (liver, lungs, etc.).

Acoelomate

(no coelom) three tissue layers with no body cavity between the gut and body wall (e.g., flatworm)

Pseudocoelomate

three tissue layers with a fluid-filled pseudocoel between the gut and body wall (partially lined by mesoderm) (e.g., roundworm)

Coelomate

three tissue layers with a fluid filled coelom fully lined by mesoderm between the gut and body wall

Deuterostomes

echinodermata and chordata

Choanoderm

innermost layer of sponge lined with choanocytes

Mesohyl

middle gelatinous connective layer of sponge

Pinacoderm

outer protective layer of sponge composed of pinacocytes

Archeocytes

act as “stem cells” in mesohyl that can differentiate into other specialized cell types; how sponges make new cell without having tissues

Spicules

Stiff spike of silica or calcium carbonate that provides structural support in the body of many sponges.

Choanocytes

A specialized, flagellated feeding cell found in sponges

Cnidocyte

A specialized stinging cell found in cnidarians (e.g., jellyfish, corals, and anemones) and used in capturing prey.

Anthozoa

no medusa stage, just polyp

Hydrozoa

medusoid and polyp stage but polyp dominates

Scyphozoa

medusoid and polyp stages, medusa dominates

Branching sponge

Encrusting sponge

Barrel sponge

Turbellaria

mainly free-living flatworms

Trematoda

parasite with 2-3 hosts

Cestoda

tapeworms; endoparasites that live in vertebrate hosts

Mesynchyme

acts as hydrostatic skeleton in platyhelminthes

Protonephridia

equipped with flame cells, where beating cilia filter interstitial fluid and pass waste through tubules out nephridiopores

Scolex

attachment point for the rest of the cestoda reproductive body

Proglottids

long series of repeating units of hermaphroditic reproductive structure