Chapter 13 Connect

Free-swimming ctenophores are able to propel themselves forward with the help of eight rows of _____ plates.

ciliated

Cnidocytes produce one of twenty different types of organelles called _____, one of which is a nematocyst.

Cnidae

Tiny organelles contained within cnidocytes are called _____.

Cnidae

Sea whips, Hydra, corals, and sea anemones are members of which phylum?

Cnidaria

Select all of the benefits provided by zooxanthellae to corals.

Facilitation of calcium carbonate deposition Recycling of phosphorus-containing wastes Food through the process of photosynthesis Recycling of nitrogenous wastes

In the polymorphic floating hydroid colonies of orders Siphonophora and Chondrophora, the feeding polyps with a single long tentacle arising from the base are known as _____.

Gastrozooids

Match each modified polyp or medusa type found in the specialized floating hydroid colonies of orders Siphonophora and Chondrophora with its function.

Gastrozooids: A modified polyp used in feeding. Dectylozooids: A modified tentacle used in prey capture. Gonophores: A modified medusa that contains ovaries or testes.

In colonial hydroids, the feeding polyps are called _____.

Hydranths

Cnidarians are dimorphic; the larval or _____ form is sessile and attached to the substrate with tentacles extended into the water column, and the adult or _____form is umbrella-shaped and adapted for a floating, free-swimming lifestyle.

Hydroid Jellyfish

Select all of the following that describe feeding in hydras.

The mouth opens into the gastrovascular cavity. Their diet often consists of small crustaceans, insect larvae, and annelid worms. Nematocysts found in the tentacles are used to subdue prey.

What type of cnidarians have a pharynx that leads to a gastrovascular cavity, which is divided into radial chambers by pairs of septa?

Sea anemones

Select all of the members of Phylum Cnidaria.

Sea anemones Sea whips Corals Jellyfishes

What statement is true regarding the dimorphic nature of cnidarians?

The polyp stage is sessile, while the medusa stage is free-swimming/floating.

Radiate animals have which of the following characteristics?

Two embryonic cell layers (endoderm and ectoderm) The process of gastrulation during development Presence of a gut cavity

Coral reefs would be most likely to occur in what environments?

Shallow tropical marine waters.

Which of the following statements are true about sponges?

Sponges are not diploblastic. Adult sponges do not have distinct cell layers.

In order to capture prey, many ctenophores trail their two long tentacles in the water, and small planktonic prey items adhere to the adhesive cells called _____.

colloblasts

Match each cnidocyte-related structure with its description.

Cnidoblast: A developing cnidocyte Cnida: Tiny capsule containing a coiled thread or filament Operculum: Covers over the end of the cnidae within cnidocytes Cnidocil: A triggerlike structure that causes the specialized organelles of cnidocytes to discharge.

Members of the phylum Cnidaria possess cells known as ______ that produce stinging organelles called ______ for defense.

Cnidocytes; cnidae

When a ctenophore is swimming forward, the cilia on the _____ plates beat in waves starting at the _____ end of the animal and ending at the _____ end.

Comb; aboral; oral

Coral reefs are composed of what substance that has been deposited by living organisms over thousands of years?

Calcium carbonate

Ctenophore prey capture and feeding can occur in which of the following ways?

Portions of a prey item may be consumed. An adhesive substance secreted by colloblasts on the surface of tentacles captures small prey items. Small prey items are collected by cilia on the body surface.

Which of the following accurately describe locomotion in ctenophores?

Some forms are sessile or creeping rather than free-swimming. They are often at the mercy of tides and strong currents. Most use ciliated comb plates to propel themselves forward. In calm water, many species rest vertically with little movement.

What are cnidocytes?

Specialized stinging cells found in cnidarians that are used in prey capture and defense.

Select all of the characteristics of sea anemones.

They use pedal discs to attach to submerged objects. They are relatively large polyps, especially compared to those of hydrozoans. A structure called a siphonoglyph draws water into the animal through the movement of cilia.

In a typical coral reef, more protected areas such as blue holes and deeper areas of the fore reef slope are inhabited by _____ corals.

octocorallian

Dimorphism occurs when an organism has what number of morphological types?

2

Examples of variations in the typical cnidarian life cycle (sessile polyp, free-swimming medusa) include

A floating colony of polyps in some hydrozoans. a missing medusa stage in anthozoans. a missing medusa stage in Hydra

Select all of the characteristics of a typical cnidarian polyp.

A mouth surrounded by tentacles at the oral end of the body Attachment to the substratum by a pedal disc or similar structure Asexual reproduction through budding, fission, or pedal laceration A gastrovascular cavity

Widespread coral bleaching is currently occurring at an unprecedented rate and is correlated with

A rise in ocean temperature.

Match each letter to its corresponding structure in cnidarian medusae.

A: Epidermis B: Mesoglea C: Gastrodermis D: Gastrovascular Cavity E: Mouth F: Tentacle

Match each of the following asexual reproduction in cnidarians with its description.

Budding: Tissues on the side of a polyp develops into another polyp that stays attached to the parent polyp. Fission: A polyp divides in half and one side of the polyp pulls away from the other side. Pedal Laceration: Tissue torn from the basal disc develops into tiny new polyps.

The life cycle of a typical cnidarian includes both a medusa and polyp stage. However, members of class _____ lack a medusa stage due to likely separating from an ancestor before the medusa evolved.

Anthozoans

How must the cilia of the comb plates move in order for a ctenophore to swim backward?

Beating in unison in waves that start at the oral end of the animal and end at the aboral end

Select all of the characteristics of members of the phylum Ctenophora.

Biradial symmetry Colloblasts Eight comblike rows of cilia

The expulsion of zooxanthellae from coral tissues that can occur as ocean temperatures increase is called coral _____.

Bleaching

In ctenophores, digestion occurs

Both extracellularly and intracellularly

Asexual reproduction in hydras occurs through the process of _____.

Budding

Which of the following are true of reproduction in hydras?

Budding occurs when outpocketings of the body wall develop into offspring. Zygotes undergo holoblastic cleavage to form a hollow blastula. They reproduce both sexually and asexually.

The asexual reproductive process involving tissue on the side of a polyp developing into another functioning polyp is known as _____; if the new polyp stays attached to the parent polyp, a(n) _____ is formed.

Budding; colony

Massive formations of calcium carbonate that are deposited by living organisms in shallow tropical marine environments are called _____ reefs.

Coral

Biradial marine animals that typically use eight rows of cilia for locomotion are members of what taxonomic group?

Ctenophore

The majority of what group of organisms is bioluminescent?

Ctenophores

Members of what cnidarian class are characterized by a dominant medusa form, with the bell being almost square in transverse section and tentacles or groups of tentacles situated at each corner of the square?

Cubozoa

Place the following steps in the typical cnidarian life cycle in chronological order, with the step following the formation of the zygote at the top of the list.

Development into a motile planula larva Settlement onto a hard surface Metamorphosis into a polyp Production of medusae through asexual reproduction

The term for an organism having two morphological types is _____.

Dimorphism

Zooxanthellae are mutualistic _____ often found in cnidarian tissues that supply the animal with food molecules derived from the process of _____.

Dinoflagellates; photosynthesis

In sea anemones, the mouth is in the center of a flat, oral _____, and the gastrovascular cavity is divided into radial chambers by pairs of primary _____.

Disc; septa

Select all of the characteristics of members of the cnidarian class Cubozoa.

Each rhopalium contains six eyes. The edge of the subumbrella turns inward to form a velarium. The base of a tentacle is differentiated into a flattened, tough blade called a pedalium.

Place the following structures of a typical cnidarian body in order, with the outermost layer at the top of the list and the innermost layer at the bottom.

Epidermis Mesoglea Gastrodermis Gastro-cavity

What type of cells serve a similar function as true mesoderm-derived muscle cells in the diploblastic cnidarian body?

Epitheliomuscular cells

Match each term for a component of a typical hydroid colony to its description.

Hydrorhiza: Rootlike stolon that attaches the colony to the substratum. Hydrocauli: Stalks produced by the rootlike stolon that make up the colony. Coenosarc: The living, tubular component of the stalks that make up the hydroid colony. Perisarc: A nonliving, chitinous sheath that acts as a protective covering over the colony stalks.

Select all the true statements regarding cnidarian mesoglea.

It contains amoeboid cells in classes Anthozoa and Scyphozoa. It is gelatinous extracellular matrix. It can contain elastic fibers. It is found between the epidermis and gastrodermis

The gelatinous, jelly-like layer that lies between the epidermis and gastrodermis in cnidarians is called _____.

Mesoglea

In this diagram of a cnidarian polyp, the letter B corresponds to the _____, the letter D corresponds to the _____ cavity, and the letter E corresponds to the _____.

Mesoglea, Gastrovascular, mouth

The most common type of cnida that is used to inject a toxin for prey capture and defense is a _______.

Nematocyst

What type of cnidarian structure can be described as a tiny capsule composed of a material similar to chitin containing a coiled filament that may bear tiny barbs?

Nematocyst

Some ctenophores, flatworms, and molluscs consume hydroids bearing _____, then store and use these stinging structures for their own defense.

Nematocysts

Although digestion in hydras is mostly extracellular, food particles can be drawn into what type of gastrodermal cells for intracellular digestion?

Nutritive-muscular cells

Select all of the factors that threaten coral reefs.

Ocean acidification Pollution Overfishing of herbivorous fishes

What organism is best described as a relatively large polyp with a crown of tentacles arranged in one or more circles around the mouth of a flat oral disc?

Sea anemone

In a typical cnidarian life cycle, a newly formed zygote develops into a motile _____ larva, which then settles onto a hard surface to develop into a _____.

Planula, polyp

If a cnidarian colony is _____, it is made up of polyps with a number of different morphologies.

Polymorphic

Within certain cnidarian colonies, a polyp may be able to reproduce asexually to form new individuals with different morphologies. Such colonies are _______.

Polymorphic

Unlike the medusa form, a typical cnidarian _____ has a body that is tubular in shape with a mouth surrounded by tentacles and a pedal disc or similar structure at the aboral end.

Polyp

Ocean acidification as a result of increasing concentrations of carbon dioxide in the atmosphere has what effect on coral reefs?

Precipitation of calcium carbonate is made more difficult.

Match each zone of a typical coral reef to its description.

Reef front/ fore reef slope: The side of the reef that faces the sea and slopes downward into deeper water Reef Crest: emergent The top of the reef that occurs in shallow water or is slightly emergent Reef Flat:The side of the reef that slopes down into the lagoon Blue Hole: Choice, A deep, cup-shaped indentation in the reef A deep, cup-shaped indentation in the reef

Select all of the true statements regarding typical cnidarian body structure.

The mesoglea lies between the epidermis and the gastrodermis. The epidermis is derived from ectoderm. The gastrodermis is an inner layer.

What is the purpose of epitheliomuscular cells in the cnidarian body?

They act as muscle cells, allowing the body and tentacles to contract and expand.

True or false: Most ctenophores are bioluminescent.

True

Select all the habitat requirements of coral reefs.

Water that is the same salinity as undiluted seawater Light

After a cnidarian nematocyst receives a stimulus to discharge, _____ rushes into the capsule, causing the _____ to open and the filament to be turned inside out. This exposes the barbs, which can then be used to inject toxin.

Water; operculum

Corals rely on their relationship with ______ for food, recycling of phosphorus and nitrogenous wastes, and assistance in the deposition of calcium carbonate.

Zooxanthellae

Mutualistic symbiotic dinoflagellates that inhabit gastrodermal cells and supply the cnidarian with products of photosynthesis are known as:

Zooxanthellae

Select all of the components of the gastrovascular system of ctenophores.

gastrovascular canals stomach pharynx mouth