Module 5 Study Guide (Apologia Marine Biology)

What are the classes of Phylum Arthropoda discussed and the common organisms in them?

Class Crustacea (shrimp, crabs, lobsters, krill), Class Pycnogonida (sea spiders) and Merostomata (horseshoe crabs)

Define Carapace and tell which organism (or phylum and class) uses it.

- armored covering over the cephalothorax of arthropods

What are the characteristics of true crabs

- have a small abdomen folded under their cephalothorax - females have a wider flattened abdomen to hold eggs - scavenge for food like shrimp

How do Cephalopods swim faster than other members of Phylum Mollusca?

In other mollusks water is taken into the mantle cavity, moves over the gills, and is released slowly through the siphon. Cephalopods, however, forcefully contract their mantle cavity and can shoot out a jetstream of water that propels them backwards.

Explain the feeding strategies of Gastropods by organism mentioned

Limpets and Abalones: Use radula to scrape algae off of rocks Cowries: Use radula to paralyze and eat worms or fish Nudibranchs: pret on hydrozoans and other invertebrates. (Some can use the nematocysts from hydrozoans it eats as protection in their own bodies)

Are hermit crabs true crabs? How do they camoflauge?

No they are not. They camouflage by covering their shells with algae or other animals.

Explain the nervous systems crustaceans have

Small brain, and more complex sensory organs. Have compound eyes made of thousands of light sensors. Can also "smell" chemicals.

What are the common names for the organisms covered in Class Gastropoda?

Snails, Nudibranchs, Abalones

Explain how arthropods grow? Why can this be dangerous?

When an arthropod grows it molts its exoskeleton. Then, it fills up with water to bloat, and grows a new exoskeleton. When the arthropod de-bloats, it now has some room to move and grow. This is dangerous because the new exoskeleton takes a few days to grow, leaving the crustacean vulnerable during this time.

Define Cephalothorax and tell which organism (or phylum and class) uses it.

fused head and thorax arthropoda

Describe the distinguishing feature(s) of each organism: Copepods, Barnacles, Amphipods and Isopods, Krill

* Copepods: Have an enlarged set of antennae that help them stay afloat. * Barnacles: Have two larva stages where they look like shrimp. Kick food in the mouth by feather-like appendages. * Amphipods: Laterally compressed *Isopods: Ventrally compressed * Krill: Planktonic filter feeders, have a cephalothorax and carapace.

Out of Mollusca, Arthropoda, and echinodermata ... * Which Has gills * Which has a complete gut * what kind of symmetry * What are each's characterising features

* Mollusca and arthropods * all 3 * M and A bilateral, E radial (bilateral when larva) * M- mantle, radula A - exoskeleton E - Water vascular system, tube feet

Explain the nervous systems in Mollusks

* The gastropods and bivalves have a set of ganglia (simple clusters of nerve cells) * Cephalopods have a very complex brain that controls specific functions. For example, they can solve puzzles, play, have rapid reflexes, imitate animals, and exhibit intense emotions like aggression.

Explain Reproduction in Mollusks

* There are typically separate sexes but some species are hermaphroditic (Like clams). * In many mollusks, fertilization occurs externally (sperm and eggs are released into the water) resulting in a trochophore larva. * In many bivalves and snails, there is a second stage of larval formation in which the larva has a tiny shell, the veliger. * Gastropods create yolk-filled sacs of fertilized eggs. * Cephalopods have internal fertilization. Males transfer a packet of sperm to the female using one of his arms. The fertilized eggs are placed in safe areas in rocks and watched over by the female (who typically ends up dying of starvation when they hatch).

What is chitin?

A carbohydrate-based substance that provides both flexibility and support.

Define chitin and tell which organism (or phylum and class) uses it.

A derivative of carbohydrates that provides both flexibility and support in mollusks shell

Define Exoskeleton and tell which organism (or phylum and class) uses it.

A jointed suit of armor encompassing not only their abdomens but also their appendages (arthropods).

What is a mantle?

A layer of tissue, surrounding the mollusk, that makes the shell by secreting calcium carbonate, and aids in respiration

Define Water vascular system and tell which organism (or phylum and class) uses it.

A network of water filled canals in echinoderms, used for locomotion and feeding

Define mantle and tell which organism (or phylum and class) uses it.

A sheath of tissue surrounding the organs of a mollusk, producing the mollusks shell and aiding in respiration

What is an operculum and what is its purpose?

An operculum is a horny plate that forms a lid over the opening of the shell of a snail when the head and foot are pulled inside. In other words, it acts like a door.

What is a radula?

An organ covered with hundreds of small teeth used to scrape food into the mouths of some organisms such as mollusks.

Define radula and tell which organism (or phylum and class) uses it.

An organ covered with hundreds of small teeth, used for scraping food into the mouths of mollusks

Define maxillipeds and tell which organism (or phylum and class) uses it.

Appendages near the mouths of crustaceans that maneuver food into their mouths

Explain the feeding process of Bivalves

Bivalves have two siphons. One to suck in seawater and one to expel seawater. They also have tiny cilia on the gills that beat back and forth creating a current. This pulls the water to the gills where plankton and food particles are trapped and swept to the mouth.

What are the Classes covered in Phylum Mollusca?

Class Gastropoda, Class Bivalvia, Class Cephalopoda

Name and briefly describe a couple distinguishing characteristics of the two other classes of mollusks.

Class Polyplacophora contains chitons that have 8 armored plates protecting their oval bodies. Class Scaphopoda contains tusk shells that are found buried in deep-water sediments and feed on microscopic organisms.

What distinguishes cuttlefishes from squids?

Cuttlefishes have fins along the sides of their bodies, whereas squids only have two on the top of their head.

Explain the digestive process of Mollusks

Food travels from their mouth through the gut, where it is exposed to enzymes released by salivary and digestive glands. The undigested food exits through the anus.

What are the three body segments of Arthropods? What is a cephalothorax, and what is it covered with?

Head, thorax, abdomen. A cephalothorax is the anterior portion. It's the head and thorax fused together. It's covered with a carapace (armored shield).

Define Head/Thorax/Abdomen and tell which organism (or phylum and class) uses it.

Head/Thorax/Abdomen - Body parts of arthropods

Explain Reproduction in Crustaeceans

Males use appendages to transfer sperm to females. Some females store this sperm to fertilize a large quantity of eggs at a later time.

Explain how the water vascular system of a sea star works

Muscles on one side of the animal can pump water through the vascular tubes to the other side. This gives additional force and can even allow the sea star to open the valves of a clam.The water vascular system connects to the outside via a porous madreporite

Name the organisms in Class Bivalvia

Mussels, Clams, oysters, and scallops.

What is a notable crustacean larva? What organisms have this?

Nauplius larvae of the copepods and the barnacles

Compare and Contrast an open and closed circulatory system

Open circulatory system is a system in which the blood flows out of the blood vessels and into body cavities, coming into direct contact with cells. A closed circulatory system, however, is a system where the blood always remains in the vessels.

Other Arthropod Classes and their distinguishing characteristics

Pycnogonida (sea spiders - feed on soft invertebrates, have 8 legs) Insecta (Live among algae and rocks) Merostomata (Horseshoe crabs, have a horseshoe carapace covering their 10 legs)

How are real pearls made? What's the difference between cultivated pearls, fake pearls, and real pearls?

Real pearls are made when an irritating bit of material, such as sand, gets caught in the an oyster's body. The oyster's mantle secretes shiny calcium carbonate that layers and creates a pearl. Real pearls have more calcium carbonate than cultivated ones (due to the size of the irritant placed in the clam in cultivated ones). Fake pearls do not have calcium carbonate.

What is the ink released by Cephalopods called?

Sepia

List five members of the phylum Enchinodermata, one from each of the following classes: Asteroidea, Ophiuroidea, Enchinoidea, Holothuroidea, Crinoidea

Sea stars, brittle stars, sea urchines, sea cucumbers, feather stars

What are the distinguishing characteristics of shrimp and lobsters?

Shrimp - Live on ocean floor where they scavenge for leftover bits of food. Can set up cleaning stations where a fish can swim up and the shrimp can crawl over its body and eat all the parasites. Lobsters - feed same as shrimp but do it at night. They can also grab prey with their large claws.

What are some organisms in Phylum Arthropoda?

Shrimp, barnacles, crabs, and lobsters

Name the organisms in Class Cephalopoda

Squid, Octopus, cuttlefish, nautilus

Besides their shape, What are some differences between squids and octopuses

Squids have 10 tentacles (8 sucker covered arms, and 2 longer tentacles surrounding their mouths), while octopuses only have the 8 arms. Also, squids have a small internal mantle shell, while octopuses completely lack a shell.

Draw and label a generalized body plan of a Gastropod

Textbook top of p. 131

What is a pen?

The internal shell in squids that is made of chitin.

What organisms are decapods? What are the distinguishing characteristics of decapods?

The organisms are shrimp, lobsters, and crabs. They have 10 legs (one pair is larger for food and protection). They have a carapace covering their cephaothorax. Have aninedible tail with short fins

Define molting and tell which organism (or phylum and class) uses it.

The process of shedding an exoskeleton and replacing it with a new one. arthropods

Why can crabs survive on land for a long time?

Their exoskeleton keeps moisture on the gills from evaporating.

What are the characteristics of Phylum Arthropoda?

They are bilaterally symmetric and have segmented bodies with an exoskeleton (made of chitin). They have muscles attached to the inside of the exoskeleton.

What are the common traits of organisms in Phylum Mollusca?

They are bilaterally symmetric, have a mantle, gills, most have a radula, and most have a shell covering their soft body. They also have complex sensory organs in their head area.

Explain the eating habits of the organisms in Class Cephalopoda

They are carnivorous, using their sucker-lined tentacles to catch food and drag it to their mouths.

What do the muscles in bivalves do?What else do some scallops use their muscles for?

They are muscles that hold the bivalves sides together. Some scallops use these muscles to help them swim short distances by creating a jet stream of water.

How do bottom dwelling crustaceans feed?

They have three pairs of appendages near their mouths called maxillipeds.

What are byssal threads and what are their purpose?

They are strong filaments that are used by some bivalves, such as mussels, to attach themselves to rocks.

Do most Cephalopods have mantles and shells?

They have a small internal mantle (like the squid), but no shell (like the octopus)

How do cephalopods camouflage?

They have chromatophores that rapidly change the organisms color.

What are the characteristics of organisms in Class Crustacea?

They have gills for obtaining oxygen, special appendages for swimming, two pairs of antennae that help them sense their surroundings, and an exoskeleton hardened by calcium carbonate.

What features do organisms in Class Bivalvia have? What do they not have, that Gastropods do?

They have large and sometimes elaborate gills, siphons, and a complete gut (one way). They do not have a radula, or a noticeable head.

Why are horseshoe crabs (Class Merostomata) called living fossils?

They haven't changed from their fossilized ancestors.

How do Octopuses obtain their food?

They live on the ocean floor and hunt for crabs and lobsters. Their hawk-like beak is used to bite into their prey. Some also can inject poison in their victims to paralyze them.

Why do Cephalopods need a closed circulatory system?

They move around a lot which would be problematic if they had an open circulatory system, due to its dependence on gravity being constant.

Do most crustaceans have teeth? if so, where are they and what are they made of?

Yes, they are made of chitin and found in the stomach

Compare and contrast the methods of reproduction used by mollusks, crustaceans, and echinoderms

a. Mollusks - fertilization is external, and in many mollusks results in a larval form b. Crustaceans - males have appendages to transfer sperm directly to the female, most have larval form as well c. Echinoderms - many broadcast gametes directly in the water. When fertilized, egg develops into a bilaterally symmetric, ciliated larva.

Define chromatophores and tell which organism (or phylum and class) uses it.

cells that can change the animal's color to match their surroundings - cephalopods

Define endoskeleton and tell which organism (or phylum and class) uses it.

developed from the internal tissue (in Echinoderms)

Define operculum and tell which organism (or phylum and class) uses it.

mollusks - A horny plate that forms a lid over the opening of the shell when the foot and head are pulled inside.

Define siphons and tell which organism (or phylum and class) uses it.

mollusks - used to suck in and expel seawater

Define Hermaphroditic and tell which organism (or phylum and class) uses it.

producing both male and female gonads, cephalopods

Define regeneration and tell which organism (or phylum and class) uses it.

sea stars can regenerate whole limbs or regenerate from two arms (if the central disk is still mostly there)

Define tube feet and tell which organism (or phylum and class) uses it.

tiny extension's of the canals in sea stars used for locomotion and sensory

Define madreporite and tell which organism (or phylum and class) uses it.

● in sea stars, connects the water vascular system to the outside.