Paleontology finals

Sponges

This are filter feeding animals and a polyp related to cnidarians

Ostium

Pore opening of a sponge

Spongecoel

Hollow internal cavity of the skeletonof a sponge where water flows.

Osculum

Opening at the top of the spongethat expels water after filtering; “little mouth”

outgoing waste

What is the purpose of the largest opening in sponges?

Pinacocytes

Leathery cover that protect the skeleton of sponges

Choanocytes

collar cells that gather food and pump water past by using their flagella

Flagellum

brings food particles close and then the particles are trapped by the sticky collar around the base

Mesohyl

gelatinous mass which contains archeocytes

Archeocytes

undifferentiated amoeba-like cells that digest food, transport nutrients, and develop into sex cells

Spongin

Fibers of an organic substance

Spicules

needle-like elements made of silica or calcium carbonate that provide support in sponges. They may be mineralized and is commonly fossilized

Ascon

Simplest sponges; simple choanocyte-lined tubes with thin walls and very short canals

Sycon

intermediate-grade sponges and have folds and indentations (called incurrent canals) in their walls.

Leucon

highly complex sponge; have thick walls with many complex canals connecting to flagellate chambers and ultimately to a spongocoel

True

True or False: Sponges reproduc both sexually and asexually

Egg cells

In sexual reproduction of sponges, they develop from the archeocytes in the mesohyl

Sperm cells

In secual reproduction of sponges, they are produced from specialized cells called choanocytes.

Osculum

this is where sponges release great clouds of eggs or sperm

Budding

In asexual reproduction of sponges, this is the process where they eventually pinch off and attach to the substrate to form a new colony

Gemmules

formed during stressful periods. They are armored, food-laden archeocytes that can resist stress and dehydration

Class Hexactinellida

this sponge class are considered glass sponges. Characterized by spicules made of silica, typically with the six rays (triaxons) of the spicules at 90° in cubic symmetry

“Venus’ flower basket” sponge (Euplectella)

best known living hexactinellids

Class Calcarea

This are considered calcareous sponges

Shallow tropical waters

Most living calcisponges are found in this environment

Class Demospongea

These are sponges with organic spicules, also called as common sponges (95% of living species) . They make their skeleton out of the protein spongin, although some also have siliceous spicules

Marine and freshwater habitat

Demosponges are found in what habitat?

Class Sclerospongea

sponges with both calcareous and siliceous spicules or no spicules at all

Stromatoporoids

Laminated calcareous fossils with vertical pillars, horizontal laminae, Mamerlons with astrorhizae

Class Sclerospongea

This sponge class is one of the most important reef builders of the Paleozoic, making bulk of the great Silurian and Devonian reef complex

Cliona

Important in the degradation and break up of shells and coral reefs

Shallow marine waters

this is what 80% of the sponges prefer when it comes to environment

Archaeocyathans

They are the first reef-building organism

Early Cambrian

What period did archaeocyathans first appear?

Intervallum

It is the space between the inner and outer walls of a archaeocyathans

Tabulae

it is the perforated horizontal plates in the intervallum in archaeocyathans

shallow cratonic platform

particular environment of archaeocyathans in shallow marine carbonate shelves

False

True or False: Archaeocyathans have low tolerance for turbiduty

Regulares

This Class of Archaeocyathans are symmetrical, well-structured skeletons with double walls and a consistent pore arrangement

Irregulares

This class in archaecyathans have less symmetry, irregular skeletal growth, and more variation in their pore structure

Cnidarians

Corals, sea anemones, and sea jellies. They have true tissues but no discrete organs

Mesoglea

noncellular jelly-like material in cnidarians

Ectoderm

It is the outer layer of cells in cnidarians that encloses a sac-like body with a mouth surrounded by tentacles at one end

Endoderm

It is the inner layer in cnidarians primarily responsible for digesting food trapped by the tentacles and pulled through the mouth into the digestive cavity

Ectoderm

responsible for secreting a skeleton in cnidarians. It contains the primitive nerve network, which causes the muscular contractions of the body in response to stimuli

Polyp

An attached, hydra-like stage of the cnidarian life cycle. Reproduces asexually by budding.

Medusa

A free-living, sea jelly–like stage of the cnidarian life cycle. It has sexual organs and releases eggs and sperm to form a planula larva

Class Hydrozoa

This class of cnidarians have no hard parts or have a flexible chitinous skeleton that rarely fossilizes.

Class Cubozoa

This class of cnidarians are known as box jellies and sea wasps. They are distinctive in that their medusa is box- or umbrella-shaped, rather than domed or crown-shaped

Class Scyphozoa

Most familiar sea jellies, They spend their lives mostly as jelly-filled medusae

Class Anthozoa

Corals and sea anemones. Most are colonial, sessile forms, with an elaborate hydra stage and little or no medusa stage

Subcalss octocorallia

common members of the modern reef fauna, with a variety of shapes and habitats. Sea fans, sea whips, sea pens, and soft corals

Subclass Zoantharia

sea anemones and stony corals