Animal Phylogeny Exam 2

What kind of cleavage pattern do Annelids have?

Spiral Cleavage

What kind of cell fate do Annelids have?

Mosaic Cell Fate

Are Annelids protostomes or deutrostomes?

Protostomes - blastula turns into the mouth first

How many germ layers do annelids have?

3 germ layers

What is different about Annelids compared to Phlatyhelminthes?

Annelids are round

What kind of body cavity do Annelids have? What does it consist of?

True ceolom - has muscle which can contract to change shape of segments - hydroskeleton for structure

What is the symmetry of Annelids?

Bilateral symmetry (have cephalization)

Are Annelids segmented?

Yes - some have limbs

What is the key feature of Annelids?

They have satae/parapodia

What is the purpose of segmentation in Annelids?

Segmentation is used to increase the efficiency of burrowing

Is segmentation a homologous triat?

NO - segmentation is not homologous for annelids, arthropods, and chordates

What do humans use Annelids for?

Annelids are used as food for fish, support for agriculture (soil aeration, compost, vermiculture), medicinal leeches, used in research, and important for the ecosystem as detrivores

Which class of Annelid contains of 80% of its species?

Polychaeta

Which class of Annelids consists primarily of Earthworms and leeches?

Clitellata

What are the different anatomical features of Annelids?

They have a head - areas of segmentation which consist of repeated units with repeated organs - tail called a pygidium

What is the parapodia?

Parapodia is a locomotory organ that helps Annelids with crawling, swimming, or anchoring, it also functions as a respiratory organ (like gills in fish)

What kind of digestive tract do Annelids have?

Complete digestive tract

What do Polychaetes eat?

Mobile Polychaetes are predators and sedentary Polychaetes consume plankton/filter feed with tentacles that have cilia and mucus

What do Oligochaetes eat?

Oligochaetes consume detritus

What do Hirudinians eat?

Hirudinians are parasites

How do Annelids transport nutrients?

Annelids have closed circulatory system - the fluids transport nutrients, wastes, and respiratory gasses - and a respiration system which diffuses nutrients across its skin or via the parapodia

What is the Nephidia in Annelids?

Nephridia is the excretory organ in Annelids which is present in each segment and has ciliated funnel which pulls in waste and tubules with capillaries to resorb water - excess waste empties out the Nephridiopore

What kind of nervous system do Annelids have?

Annelids have a cerebral ganglia (brain) which connects to ventral nerve cords and giant axons that increases signal speed

What kind of sense organs do Annelids have?

Annelids have eyes (some have eyespots and some have more complex structures), statocysts, palps (used for sensory and feeding) and antennae

How do Annelids locomote?

Most use the parapodia for movement or as anchors - Annelids also have longitudinal and circular muscles which allows for peristalsis and anchoring with satae - they also can undulate which uses only longitudinal muscles

How can Annelids reproduce?

Annelids can reproduce asexually via budding (in polychaetes) or sexually via external fertilization

What type of larvae do Annelids have?

Early larvae is called trochophore

How many sexes do Annelids have?

Annelids can have separate sexes, sexes which can change, or be hermaphroditic

What are the two classes for Annelids

Class Clitellata and Polychaetes

What does the class Clitellata consist of?

Oligochaetes (earthworms) and Hirudinea (leeches)

What do species in Class Clitellata lack?

They have no parapodia

What feature is unique to the class Clitellata?

Clitellum (make a cocoon for development)

What kind of digestive features do Class Clitellata exhibit? What type of consumers are they?

Clitallata are detrivores and they have an unsegmented digestive tract - they have a crop to store food and a gizzard to grind it - their digestion and absorption occurs in the intestine

What are the purpose of the satae in class Clitellata?

The satae are bristle moved by tiny muscles which can act as anchors - when longitudinal muscles contract, segments widen, pushing setae against the soil

How does class Clitellata reproduce?

1) Align in opposite direction, ventral surfaces, together

2) Exchange sperm

3) After copulation, Clitellum secretes caccon

4) Cocoon passes forward: eggs and sperm poured into it

5) Fertilization occurs in cocoon; cacoon slips overhead

6) Young worm emerge from cocoon (no trochophore)

What is different about Hirundinea (leeches) in the class Clitellata?

Hirundinea (leeches) do not have setae and they have anterior and posterior suckers - their Clitellum is only present during breeding

Where do Hirundinea (leeches) live?

Most are freshwater species

How do Hirundinea (leeches) obtain nutrients?

Hirundinea (leeches) are endoparasites and they secrete an anticoagulant in their saliva to hide their bite

How do Hirundinea (leeches) reproduce?

Hirundinea (leeches) transfer sperm by their penis or hypodermic impregnation - their temporary clitellum secretes cocoon and bury it in the mud

What is the name for the worms that infested the sewers under Cameron village? What group are they connected with?

Tubifer worms or sludge worms which is a Oligochaetes

What are some different features about Polychaetes?

Polychaetes have a well-differentiated head with well-developed sense organs (eyes, tentacles, and sensory palps)

Polychaetes do have parapodia with many satae in bundles

What type of Polychaetes are the family scale worms? What is a unique feature about them?

Scale worms are mobile polychaetes which have flattened bodies covered in with broad scales

What type of Polychaetes are the family clamworms? What is a unique feature about them?

Clamworms are mobile polychaetes which are the most abundant of polychaetes

What type of Polychaetes are the family fireworms? What is a unique feature about them?

Fireworms are mobile polychaetes which have hollow, brittle satae containing poisonous neurotoxins - fireworms also feed on cnidarians like corals and sea anemones

What type of Polychaetes are the family tubeworms? What is a unique feature about them?

Tubeworms are sedentary polychaetes which burrows and uses cilia/mucus to obtain food

What type of Polychaetes are the family fanworms? What is a unique feature about them?

Fanworms are sedentary polychaetes which have ciliated tentacles to help move food into their mouths

What type of Polychaetes are the family zombie (bone-eating) worms? What is a unique feature about them?

Zombie worms are sedentary polychaetes which are common at whale sites

What other early species are Phyla Annelids related to?

Annelids are related to Cambrians and Edacarians

What is important about Spoonworms?

Spoonworms have loss of segmentation, they burrow in empty shells or rocky crevices, and they have a ciliated groove on proboscis which gathers detritus

What type of polychaetes are parchment worms and why are they unique?

Parchment worms are sedentary polychaetes which live in burrows where they can pull water into burrow via parapodia and push water out in exit of burrow

What is important about the phylum Sipincula (peanut worms)?

Sipuncula (peanut worms) are sendentary worms which live in burrows, snail shells, and coral (near benthic zone of tropical areas), they have no segmentation or setae, a retractable proboscis, and trochophore larvae

What is the cleavage for mollusks?

Spiral

What is the cell fate for mollusks?

Mosaic

How many germ layers do molluks have?

3 germ layers

What kind of body cavity do mollusks have?

True coelom

What is the symmetry of mollusks?

Bilateral (with cephalization)

Do mollusks have segmentation?

No segmentation/limbs

What kind of structures do mollusks have?

They can have hydro, exo, or endoskeletons

How is the phylum Mollusca ranked among the other phylums?

Phylum Mollusca is the third largest phylum in general and the largest marine phylum

What is the study of mollusks called?

Malacology

What is the head-foot region in mollusks?

The head-foot region is the area of the mollusk that contains feeding, cephalic sensory, and locomotor organs

What is the visceral mass of mollusks?

The visceral mass is the area of the mollusk which contains digestive, circulatory, respiratory, and reproductive organs

What is the radula?

The radula is a unique feature to mollusks which is a rasping, tongue-like organ with up to 250,000 teeth

Which class of mollusks do not have a radula? Why?

Bivalves because they are filter feeders

How is the foot region used in limpets, bivalves, gastropods, and cephalopods?

Foot used as an attachment disc for limpets

Foot used for digging in bivalves

Foot used for gliding for gastropods

Foot used as Siphon jet/arms in cephalopods

How does the foot work in mollusks?

Mucus in foot aids in adhesion or gliding with cilia

What is the most defining trait of mollusks?

The mantle and mantle cavity

What is the mantle in mollusks?

The mantle is on the dorsal body wall which secretes shell that covers visceral mass

What is the mantle cavity?

The mantle cavity houses the gills or lungs for gas exchange and digestive and excretory wastes and gametes empty into it

What is the Periostracum in mollusks?

The Periostracum is the outer protein layer

How is the Periostracum different in freshwater mollusks? Why?

The Periostracum is thicker in freshwater mollusks because it is needed to protected against acid from leaf decay

What is the Prismatic layer?

The prismatic layer is the layer of the shell which is closely packed with CaCo3

What is the Nacre?

The Nacre is the innermost layer which is next to the mantle and it is secreted continuously throughout a mollusks life

What kind of digestive system do mollusks have?

Complete digestive system - with anus emptying into mantle cavity

What kind of circulatory system do mollusks have?

Most mollusks have a open circulatory system with a pumping heart and few vessels

Which class of mollusks does not have an open circulatory system?

Cephalopods

How are mollusks able to respire?

Mollusks will either have gills or lungs (depending in what environment they live in) which allows them to respire

What kind of excretory features do mollusks have?

Mollusks can either have kidneys or nephridia

What is something unique that travels through mollusks kidneys?

Kidney ducts can also discharge sperm and eggs having the gonads push them out

What kind of nervous features do mollusks have?

Mollusks have a cerebral ganglia which is found near the pharynx

They also have 2 nerve cord pairs (in food and lower visera)

Which class has the most advanced invertebrate brain?

Cephalopods

What kind of sensory organs do mollusks have?

Mollusks sense organs vary depending on how they live (stationary less complex, while mobile/predators are more complex)

How do mollusks reproduce?

Most mollusks have separate sexes which can involve external or internal fertilization leading to an egg hatching and producing trochophore larva

Which class of mollusks has some species which are hermaphroditic?

Some gastropods are hermaphorditic

What kind of defense features do mollusks have?

Mollusks can have a shell, venom/poison, ink, mucus, camouflage, mutualism, etc.

Which class of mollusks is the most diverse?

Gastropods

What kind of environments do gastropods live in?

Gastropods live in all environments (marine, freshwater, terrestrial)

What is the main defense for gastropods?

Shells are the main defense for gastropods (although still some reduced or lost)

What kinds of gastropods live on land? In the ocean?

Land: snails and slugs

Ocean: limpets, whelks, conches, periwinkles, cowires

Nudibranchs, sea hares, sea butterflies

How many pieces make up a gastropod shell?

A gastropod shell is one-piece

What is the operculum? Which class exhibits this?

The operculum is a structure that covers aperture to prevent water loss - Gastropoda exhibit this mostly in aquatic snails

What did ancestral shells look like?

Ancestral shells looked more like flat spirals which developed into the helix shape

What is gastropod torsion?

Gastropod torsion is when the mantle cavity and anus rotate to the right side until opening above head

What are the results of gastropod torsion?

Resulting of gastropod torsion the viscera shift from left to the right side, the nerve cords form a figure eight, and fouling can occur

What is fouling?

Fouling is when the anus empties over the mouth and sense organs

When does gastropod torsion occur?

Gastropod torsion occurs during development and the shell shifts 180 degrees

What kind of feeders are gastropods?

Gastropods can be all kinds of feeders (herbivore, scavenger, or carnivore) because the radula allows for feeding variation

How do gastropods respire (both marine and terrestrial)?

Marine gastropods respire via gills in the mantle cavity or “lung” (the vascular area in the mantle)

Terrestrial gastropods respire via lung which opens to the outside by pneumostome (small hole-looking part near mantle cavity)

How can gastropods reproduce?

Gastropods have dioecious and hermaphroditic species (but no self-fertilization)

Land snails lay eggs in the ground/under logs and aquatic snails lay eggs in gelatinous masses

Which class of mollusks has species with their foot modified into tentacles (and a funnel)?

Class cephalopods