Term
| The superphylum Gnathifera includes which two phylum? |
|
Definition
| Rotifera and Acanthocephala |
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|
Term
| Having a pseudocoelom like the Gnathifera is advantageous for.... |
|
Definition
-distribution of nutrients
-removal of wastes
-space for storing gametes during maturation |
|
|
Term
| Gnathifera have a hydrostatic skeleton used for locomotion and.... |
|
Definition
| moving food through the digestive tract (which lacks muscles) |
|
|
Term
| The Gnathifera body wall consists of five things. What are they? |
|
Definition
1. a syncytial epidermis
2. muscles around the pseudocoel
3. gonads within the pseudocoel
4. a digestive tract
5. excretory organs |
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|
Term
| The Gnathifera exhibit eutely. What is eutely? |
|
Definition
| Growth through cell size rather than cell number where the maximum number of cells is fixed |
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Term
| Most rotifers are found in freshwater. Name the other 6 common characteristics. |
|
Definition
-100-500 micrometers long
-free-living
-short-lived
-omnivores
-active suspension feeders
-parasites of annelids and arthropods |
|
|
Term
| What are corona and what are their function? |
|
Definition
| They are the 2 ciliated anterior lobes of the rotifer body. They bring water and plankton to the mouth. |
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|
Term
| The mastax in rotifers is.... |
|
Definition
| A muscular, modified pharynx with trophi |
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|
Term
|
Definition
| found in rotifers; they grind food and are made of acid mucopolysaccharide infused with calcium |
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Term
| Rotifers have toes and spurs....what's the difference? |
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Definition
| Toes are found on the foot (touching to surface) and range from 0 to 4; spurs do not touch the surface and are modified toes |
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|
Term
| The pedal glands found in rotifers are... |
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Definition
| Like cement glands of earlier organisms; they are ducts that open over the toes and secrete a sticky substance |
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|
Term
| Rotifer locomotion involves.... |
|
Definition
| looping, swimming using coronal cilia, free swimming larvae |
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|
Term
| How do sessile rotifers move? |
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Definition
| They actually create permanent attachment through pedal gland secretions by building a tube from debris, sand grains, or fecal pellets |
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Term
| Describe the digestive system of rotifers. |
|
Definition
-It is tubular with an anterior mouth and a posterior anus
-Extracellular in the stomach where gastric glands release enzymes
-The cloaca accepts waste that will be passed out through the anus |
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|
Term
| The nervous system of rotifers is composed of... |
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Definition
| A bi-lobed brain with a photoreceptor, sensory receptors and antennae that serve as chemoreceptors and mechanoreceptors |
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|
Term
| To accomplish excretion and water balance, rotifers.... |
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Definition
| Allow diffusion to occur across their body surface; protonephridia with flagella send waste to the bladder then to the cloaca |
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Term
| Describe asexual reproduction in rotifers. |
|
Definition
-It is called Parthenogenesis
-All females are amictic (unfertilized and diploid) and do not need sperm to reproduce
-Diploid females make diploid eggs that become more diploid females in good environmental conditions
-This causes LOW genetic variation |
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|
Term
| Describe sexual reproduction in rotifers. |
|
Definition
-When a negative environmental stimulus is present, diploid females undergo meiosis
-A haploid egg (mictic egg) is produced and hatches into a haploid male
-The male produces haploid sperm and combines with mictic eggs creating more resting diploid eggs
-A good environmental stimulus triggers the eggs to hatch out (all of these diploid eggs hatch as females) |
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Term
| What makes rotifer males so short lived in comparison to rotifer females? |
|
Definition
| Males are non-feeding, have no mouth or anus, fast swimmers, and only live a few days |
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|
Term
| How many eggs does a rotifer female create in her lifetime? |
|
Definition
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|
Term
| What is the phylum name for spiny headed worms? |
|
Definition
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|
Term
| Spiny headed worms (Acanthocephalans)have three common characteristics. What are they? |
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Definition
1. They are all gut parasites of vertebrates (especially freshwater fish)
2. Intermediate hosts are usually arthropods
3. They are gonochoristic (have separate sexes) |
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|
Term
| Spiny headed worms have cement glands. What do these do? |
|
Definition
| They produce a sticky substance that plugs the female vagina after mating |
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|
Term
| The proboscis of spiny headed worms is filled with fluid and allows... |
|
Definition
| attachment to the gut wall of the host |
|
|
Term
| Spiny headed worms (Acanthocephalans) have no digestive tract and females have no well-defined ovary. Describe the female system. |
|
Definition
-They have fragments of the ovary called ovarian balls that float around in a ligament sac.
-Mature eggs enter the uterus via the uterine bell |
|
|
Term
| Explain the general life cycle of an Acanthocephalan. |
|
Definition
-An encysted acanthor stage exits the definitive host in feces.
-The acanthor stage is eaten by a crustacean like an ostracod (the intermediate host).
-Here it develops into the infective stage.
-The intermediate host is eaten by a freshwater snail, the transport host.
-No development occurs here, but it is required for the parasite to reach the definitive host.
-The snail is eaten by the definitive host, a turtle, where the acanthocephalan reaches adulthood. |
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|
Term
| The Ribbon Worms belong the which phylum? |
|
Definition
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Term
| The Nemerteans have ____, _________ bodies. They are __________ flattened. They occur in _____ water. They burrow into _____ or are _____ _____, or ____ __ ______. They occupy _______ (many species), _______ (one genus), ________ _______ ________ _______ (a few species). |
|
Definition
*soft, unsegmented
*dorsoventrally
*shallow
*sediment, under rocks, mats of algae
*marine, freshwater, tropical moist terrestrial environments |
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|
Term
| Nemerteans have 8 similarities to Turbellarians. Name all 8 of them. |
|
Definition
1.Acoelomates- parenchyma in some species
2.Move via cilia embedded in a mucous layer by waves of muscle contraction
3.Circular, longitudinal, and dorsoventral muscles
4.Ladder-like arrangement of longitudinal muscles
5.Pigmented photoreceptors
6.Statocysts
7.Protonephridia
8.Digestion is primarily intracelluar |
|
|
Term
| How are Nemerteans different from Turbellarians? |
|
Definition
-Molecularly, they have no recent common ancestor.
-Have a true circulatory system
-Have a complete digestive tract
-Have a muscular eversible proboscis housed in a fluid filled cavity called the rhyncocoel |
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|
Term
| Nemerteans have a circulatory system. Describe it. |
|
Definition
-It contains well-defined contractile vessels.
-No true heart, no one-way valves
-Blood circulates multidirectionally
-A few species have hemoglobin |
|
|
Term
| The digestive system of Nemerteans is... |
|
Definition
*One-way, meaning they have a mouth and an anus.
*The food is moved via ciliary action
*Nutrients are distributed by the circulatory system |
|
|
Term
| IS the proboscis distinct from the digestive tract of Nemerteans? |
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Definition
| Yes, it is contained in a ryhncocoel (a fluid-filled cavity). The muscles contract around the rhyncocoel and the proboscis turns inside out because of fluid displacement. |
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|
Term
| Describe the 2 ways Nemerteans are viewed as predators. |
|
Definition
1.The stylet pierces the prey and releases a paralyzing toxin into the wound.
2.The proboscis wraps around the prey, and the proboscis retractor muscle pulls the proboscis and the prey in |
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|
Term
| What basic information is known about Nemertean reproduction? |
|
Definition
-Asexual reproduction by fission or fragmentation is rare
-Most are gonochoristic
-Few are protandric hermaphrodites: they begin life as males and become females as they age
-they rely on external fertilization |
|
|
Term
| What is the key way the proboscis is used by Nemerteans? |
|
Definition
| *The proboscis function makes use of the hydrostatic skeleton for food capture |
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|
Term
| Molluscs occupy habitats ranging from.... |
|
Definition
-the tropics to polar seas
-fresh and salt waters
-terrestrial habitats
-burrowers, borers, pelagic (open ocean), benthic |
|
|
Term
|
Definition
*filter feeders
*carnivores
*herbivorous grazers |
|
|
Term
| The foot region of a mollusc is.... |
|
Definition
-ventral in position
-highly muscular
-used for locomotion or attachment |
|
|
Term
| The head region of a mollusc contains three parts which are... |
|
Definition
1. the mouth
2. the radula-a protrusible feeding organ
3. specialized sensory organs |
|
|
Term
| The radula is the feeding organ of a mollusc. What details are important about this organ? |
|
Definition
*a firm ribbon of chitin and protein
*made up of 2 rows of chitinous teeth
*produced from a radular sac and supported by the odontophore
*the buccal mass is extended and the radular ribbon is moved forward then pulled back for feeding
*new teeth are produced by the radular sac as teeth get worn away |
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|
Term
| The visceral mass of a mollusc contains most of the internal organs such as... |
|
Definition
-the ones needed for digestion, excretion, reproduction, circulation, and the nervous system
-molluscs have nephridia for osmoregulation and waste removal |
|
|
Term
| The mantle of a mollusc hangs down on each side of the body. It is the skin... |
|
Definition
-Growing out of the dorsal side of the visceral mass
-Has 2 functions: protecting the visceral mass and secreting the shell |
|
|
Term
| What is the mantle cavity of molluscs? |
|
Definition
-the space between the visceral mass and the mantle
-it houses the ctenidia (molluscan gill) that are used in respiration and collection/ sorting of food |
|
|
Term
| Ctenidia allow molluscs to achieve... |
|
Definition
| A 100% gas exchange rate called counter current exchange; The high oxygen concentration of water decreases as the low oxygen concentration of the blood increases. |
|
|
Term
| Co-current exchange allows for... |
|
Definition
| An exchange rate of about 50% |
|
|
Term
| Cross current exchange allows for... |
|
Definition
| An exchange rate of about 60-70% |
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|
Term
| The coelom of molluscs is restricted to... |
|
Definition
| The area around the heart and gonads; it has been reduced over time because these animals are not very active |
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|
Term
| Describe the variety in molluscan shells, which are secreted by the mantle. |
|
Definition
*one piece-gastropods
*two equally sized valves-bivalves
*8 transverse valves-polyplacophorans
*reduced or absent-cephalopods and some gastropods |
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|
Term
| Name and describe the outermost layer of the molluscan shell. |
|
Definition
| The periostracum- a thin, horny layer made of conchiolin; growth only occurs at the shell margin |
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|
Term
| Name and describe the middle layer of the molluscan shell. |
|
Definition
| The prismatic layer- calcite prisms (vertical calcium carbonate crystals)surrounded by protein (conchiolin); growth only occurs at the shell margin |
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|
Term
| Name and describe the innermost layer of the molluscan shell. |
|
Definition
| The nacreous (shiny layer)- calcium carbonate surrounded by protein, deposited as sheets parallel to the surface; it is deposited continuously |
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|
Term
| How are the Chitons classified? |
|
Definition
| Phylum Mollusca, Class Polyplacophora |
|
|
Term
| These are common in intertidal zones, have 8 overlapping and articulating plates that are partially or wholly covered by the mantle, and the foot is over the entire ventral surface. |
|
Definition
|
|
Term
| What are the downfalls associated with being a chiton? |
|
Definition
-More tissue exposure means there is a higher chance of drying out
-Ganglia are poorly developed, thus they have a simple ladder-like nervous system
-Sensory structures are reduced
-Have no statocyst, no eyes, and no tentacles |
|
|
Term
| Most chitons (Class Polyplacophora) are herbivores and have.... |
|
Definition
| Sugar glands that release amylase into the stomach |
|
|
Term
| Snails and slugs are classified as.... |
|
Definition
| Phylum Mollusca, Class Gastropoda |
|
|
Term
| Gastropods are attached to their shells by.... |
|
Definition
|
|
Term
| What is an operculum seen in gastropods? |
|
Definition
| A proteinaceous shield on the foot that may be strengthened with calcium carbonate |
|
|
Term
| The gastropod shell leads to the left side of the body to... |
|
Definition
| Balance the center of mass of the organism over the foot |
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|
Term
| The shell of most gastropod species coil clockwise, making them "right-handed" shells or.... |
|
Definition
|
|
Term
| Sinister shells of gastropods are described as.... |
|
Definition
| Shells that coil counterclockwise, making them "left-handed" shells |
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|
Term
| In dextral shells, there are 4 certain structures that are reduced or absent on the right side of the shell. What are they? |
|
Definition
1. Ctenidium (gill)
2. Osphradium (chemo/ tactile receptor)
3. Heart auricle
4. Nephridium (kidney) |
|
|
Term
| Gastropods undergo torsion as embryos or larvae. What is the adaptive significance of this? |
|
Definition
-The center of gravity is moved forward for stability
-Ctenidia are headed into the current which facilitates aeration
-The osphradia are positioned in the direction of locomotion |
|
|
Term
| Snails and slugs undergo torsion as embryos or larvae. Why is this a disadvantage? What have some species done to accommodate? |
|
Definition
*The visceral mass is rotated 180 degrees relative to the head/foot
*The anus discharges over the head!!
-Some species have compensated by exhibited detorsion such as sea hares and sea slugs (Opisthobranch mollusca) |
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|
Term
| Gastropods move by pedal waves. Describe this movement. |
|
Definition
*Dorsoventral and trasverse muscles contract, squeezing the foot forward
*Edges of the foot are sealed with mucous causing negative pressure in the area of contraction
*The negative pressure causes the dorsoventral muscle to re-extend |
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|
Term
| Retrograde waves are one type of pedal waves. Describe this type. |
|
Definition
| Retrograde waves- direction of the contraction is opposite to the direction of movement (anterior to posterior) |
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|
Term
| Direct waves are a specific type of pedal waves. Describe them. |
|
Definition
| Direct waves- direction of the contraction is in the same direction as the animal (posterior to anterior) |
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|
Term
| Animals such as clams, oysters, shipworms and mussels are classified as.... |
|
Definition
| Phylum Mollusca, Class Bivalvia |
|
|
Term
| The class Bivalvia includes animals with hinged shells,.... |
|
Definition
-adductor muscles that keep the shell closed
-a ligament that allows the shell valves the spring open when the muscles relax |
|
|
Term
-The body and foot are laterally compressed
-No head or sensory structures
-No radula/odontophore complex |
|
Definition
| The bivalves (Class Bivalvia) |
|
|
Term
-Spacious mantle cavity
-Sedentary or sessile
-Most are marine, 10-15% freshwater, none are terrestrial
*What Class? |
|
Definition
|
|
Term
| Lamellibranch bivalves have siphons and gills. What is the significance of these two structures? |
|
Definition
| Siphons are tubular extensions of mantle tissue located posteriorally. There is always an incurrent and excurrent siphon. Gills generate currents through the siphons. They collect food particles and are used in gas exchange. |
|
|
Term
| How are invasive species significant in regards to filtering capacity of lamellibranch bivalves? |
|
Definition
| Zebra mussels can filter up to 1400 gallons of water in an hour where as native oysters can only filter 8-10.5 gallons an hour. |
|
|
Term
| Describe lamellibranch bivalve digestion. |
|
Definition
*Crystalline style is found in the stomach
*It is made of structural protein and contains digestive enzymes
*Cilia in the style sac cause the crystalline style to rotate
*The abrasion against the gastric shield releases enzymes |
|
|
Term
| Lamellibranch bivalves that attach to hard substrata do so by one of three methods. Name and describe them. |
|
Definition
1. Byssal threads: Proteinaceous liquid is secreted by the byssal gland and it runs down a groove along the foot. It then solidifies upon contact with the sea water.
2. Cement one valve to the substrate: An organic adhesive is produced first by the foot then the mantle. Protein, iron and calcium carbonate make up the adhesive. Calcium carbonate is affected by ocean acidification.
3. Unattached: use valves for short bursts of swimming |
|
|
Term
| What classification do the tooth shells and tusk shells belong to? |
|
Definition
| Phylum Mollusca, Class Scaphopoda |
|
|
Term
| Tooth shells and tusk shells HAVE: |
|
Definition
-Foot
-Mantle Cavity
-Mantle
-Radula
-Shell |
|
|
Term
| Tooth shells and tusk shells LACK.... |
|
Definition
*Ctenidia
*Heart
*Circulatory System
*Osphradium (sensory receptors) |
|
|
Term
| What are some general characteristics of tooth shells and tusk shells? |
|
Definition
-Water moves in and out of the same opening
-They consume small organic particles, small bivalves, and foraminiferans
-Have captacula: ciliated tentacles with a sticky bulb at the end used for food capture (each animal has 100-200) |
|
|
Term
| Phylum Mollusca, Class Cephalopoda includes.... |
|
Definition
| The octopus, squid, cuttle fish, and the nautilus |
|
|
Term
|
Definition
~Ctenidia
~Radula
~Mantle Cavity
~Foot-modified into a siphon
~Head-anterior margin drawn out into the arms or tentacles; sensory structures are well-developed |
|
|
Term
| In all cephalopods except the _______, the _____ is greatly reduced. |
|
Definition
|
|
Term
| In the nautilus, the shell chambers are connected by the.... |
|
Definition
| Siphuncle which is a calcified tube with vascularized tissue |
|
|
Term
| What is unique about the nautilus alone? |
|
Definition
-It exists in the outer chamber of the shell
-The shell is divided by septa
-It is the only cephalopod with a shell |
|
|
Term
| -The siphuncle controls the amount...; -Enzymes concentrate solutes.... |
|
Definition
-of gas and fluid in chambers
-inside or outside siphuncluar tissue |
|
|
Term
| If solute concentration inside the chamber increases... |
|
Definition
*Fluid in the chamber increases
*Gas in the chamber decreases
--Buoyancy goes down |
|
|
Term
| If solute concentration inside the chamber decreases... |
|
Definition
-Fluid in the chamber decreases
-Gas in the chamber increases
~Buoyancy goes up |
|
|
Term
| What is the minimal shell of a squid called? |
|
Definition
| A pen: it is an internal thin, stiff, proteinaceous sheet |
|
|
Term
| An octopus has no shell at all, but the brain and visceral mass.... |
|
Definition
| Are still distinct within the body of the organism |
|
|
Term
| Most cephalopods have chromatophores. What are these and what are they used for? |
|
Definition
| They are pigment cells that overlay iridocytes (reflective cells) that allow camouflage. They are used for courtship and defensive behaviors too. |
|
|
Term
| Photophores are common in mid and deep water squid. What are they and how are they used? |
|
Definition
| They are cells that produce light through bioluminescence. Flashes may startle predators and the cells make it harder to see from below during the day. |
|
|
Term
| The ink sac found in cephalopods is associated with their digestive system. What else is important about it? |
|
Definition
*The ink is discharged through the anus
*The ink is made up mainly of mucus and melanin.
*They form a cloud that confuses the predator and changes it's mood or behavior because the ink may be mildly narcotic |
|
|
Term
| Cephalopods have ctenidia, but they do not use a countercurrent exchange system. What do they use instead and how do they compensate for it? |
|
Definition
| They have a co-current exchange system and they compensate for the low exchange rate by having rapid muscle-generated water movement and a greater surface area on their gills created by more folding. |
|
|
Term
| Class Cephalopoda have what type of circulatory system? |
|
Definition
| A CLOSED circulatory system |
|
|
Term
| Cephalopods have a ______ heart and ____ ________ hearts. |
|
Definition
|
|
Term
| What is hemocyanin and what is the only class to have it? |
|
Definition
| It is an oxygen transport protein that contains copper instead of iron, so the blood is blue. It is only seen in the Class Cephalopoda. |
|
|
Term
| The systemic heart of cephalopods.... |
|
Definition
| Receives oxygenated blood from the gills and sends it back to the tissues |
|
|
Term
| These increase blood pressure to help push blood through tiny gill capillaries |
|
Definition
| The two branchial hearts of cephalopods |
|
|
Term
| The Class Cephalopoda has a unique foot modified into.... |
|
Definition
*A funnel, muscular arms, and/or extensible tentacles
*Arms and tentacles number 8-10 (80-90 arms in the nautilus)
*The mouth lies in the center of the foot |
|
|
Term
| Cephalopods are the only class to have a HIGH degree of cephalizaton. This means.... |
|
Definition
*They have a large, well-developed brain
*Can learn and distinguish objects based on shape, color intensity, and texture, but NOT wieght |
|
|
Term
| Organisms in the class Cephalopoda do not behaviorally respond to sound. Why? |
|
Definition
| Even though the statocyst is affected by sound stimuli, the sound is not processed in their brain. This protects them from stunning/paralyzing sounds made by predators like dolphins and whales. |
|
|
Term
| An example of convergent evolution can be seen in the octopus, squid and cuttle fish.... |
|
Definition
EYES!
*Mammals-focusing on things by changing the shape of their lens
~Cephalopods (except the nautilus) move their lens toward or away from the retina to focus on something |
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