Exam 33: An Introduction to Invertebrates

Use the following information to answer the questions below. This nudibranch, a type of sea slug, has many reddish cerata on its dorsal surface, as well as two, white-tipped rhinophores located on the head. The nontaxonomic term sea slug encompasses a wide variety of marine gastropods. One feature they share as adults is the lack of a shell. We might think, therefore, that they represent defenceless morsels for predators. In fact, sea slugs have multiple defences. Some sea slugs prey on sponges and concentrate sponge toxins in their tissues. Others feed on cnidarians, digesting everything except the nematocysts, which they then transfer to their own skins. Whereas the most brightly coloured sea slugs are often highly toxic, others are nontoxic and mimic the colouration of the toxic species. Their colours are mostly derived from pigments in their prey. There are also sea slugs that use their colouration to blend into their environments. -By which structures are nematocysts most likely to reach the skin of sea slugs?

In incomplete metamorphosis, the young ________, while in complete metamorphosis, the young ________.

Which of the following is true of members of the phylum Cnidaria?

The heartworms that can accumulate within the hearts of dogs and other mammals have a pseudocoelom, an alimentary canal, and an outer covering that is occasionally shed. To which phylum does the heartworm belong?

Use the following information to answer the questions below. This nudibranch, a type of sea slug, has many reddish cerata on its dorsal surface, as well as two, white-tipped rhinophores located on the head. The nontaxonomic term sea slug encompasses a wide variety of marine gastropods. One feature they share as adults is the lack of a shell. We might think, therefore, that they represent defenceless morsels for predators. In fact, sea slugs have multiple defences. Some sea slugs prey on sponges and concentrate sponge toxins in their tissues. Others feed on cnidarians, digesting everything except the nematocysts, which they then transfer to their own skins. Whereas the most brightly coloured sea slugs are often highly toxic, others are nontoxic and mimic the colouration of the toxic species. Their colours are mostly derived from pigments in their prey. There are also sea slugs that use their colouration to blend into their environments. -Which structure do sea slugs use to feed on their prey?

Use the following information to answer the questions below. Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips. -The crown-of-thorns sea star, Acanthaster planci, preys on the flesh of live coral. At times, these sea stars undergo poorly understood population explosions. What impact should such explosions have on those sea slugs that bear cerata (cerata contain nematocysts)? Population explosions of this sea star should

Which of the following describe(s)echinoderms?

Use the following information to answer the questions below. Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips. -The parapodia of polychaetes have a function most similar to that of

Use the following information to answer the questions below. Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips. -The lateral flaps of planaria heads have a function most similar to that of

How many of the following are characteristics of at least some members of the phylum Cnidaria? 1. a gastrovascular cavity 2. a polyp stage 3. a medusa stage 4. cnidocytes 5. a pseudocoelom

You find a small animal with eight legs crawling up your bedroom wall. Closer examination will probably reveal that this animal has

Use the following information to answer the questions below. Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips. -A natural predator of the crown-of-thorns sea star is a mollusc called the Giant Triton, Charonia tritonis. If the triton uses a radula to saw into the sea star, then to which clade should the triton belong?

Infection with which parasite might cause excessive elasticity in human skeletal muscles?

The teacher was unaware of the difference between suspension feeding and predation. The teacher thought that providing live copepods (2 mm long)and feeder fish (2 cm long)would satisfy the dietary needs of all of the organisms. Consequently, which two organisms would have been among the first to starve to death (assuming they lack photosynthetic endosymbionts)?

Use the following graph to answer the questions below. Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates. -Aside from the density of dinoflagellates in P. ianthina skin, how many of the following factors can affect whether or not the endosymbiotic dinoflagellates promote the sea slug's survival (assuming latitudes above or below Earth's equator)? 1. day length 2. height of sun above the horizon 3. cloud cover 4. depth at which P. ianthina lives 5. water clarity

Use the following information to answer the questions below. Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips. -The sharp, inch-long thorns of the crown-of-thorns sea star are its spines. These spines, unlike those of most other sea stars, contain a potent toxin. If it were discovered that crown-of-thorns sea stars do not make this toxin themselves, then the most likely alternative would be that this toxin is

The sea slug Pteraeolidia ianthina can harbour living dinoflagellates (photosynthetic protists) in its skin. These endosymbiotic dinoflagellates reproduce quickly enough to maintain their populations. Low populations do not affect the sea slugs very much, but high populations (> 5 × 10⁵ cells/mg of sea slug protein) can promote sea slug survival. -If 100 000 sea slug cells together contain 1.0 mg of protein, then what is the minimum number of dinoflagellates per sea slug cell that constitutes a "high," and therefore beneficial, population?

Humans most frequently acquire trichinosis by

Use the following information to answer the questions below. A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from university. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly "jet" through the water. Watching further, she is able to conclude that the "mystery organisms" are ambush predators, and their prey includes everything from insects to small fish and tadpoles. -Sarah had learned that ancestral (Carboniferous era)dragonfly species were much larger than extant dragonfly species are, with wingspans of 70 cm. This struck her as odd, because she had also learned that one of the things that keeps insects small is their relatively inefficient respiratory system. Which two hypotheses might help account for the large size of ancestral dragonflies? 1. If the atmosphere during the Carboniferous era had featured a higher oxygen content than the modern atmosphere, then the tracheae might have been a sufficient means for oxygen delivery to the interior tissues. 2. If large size was a drawback, then the large dragonflies underwent extinction, which explains why all extant dragonflies are smaller. 3. If the ancestral dragonflies had possessed muscles that permitted effective ventilation of the tracheae, then the tracheae might have been a sufficient means for oxygen delivery to the interior tissues. 4. If ancestral dragonflies existed during greenhouse conditions, then they must have survived by decreasing their activity levels, such as no longer capturing prey in flight. Thus, for them, an ineffective respiratory system was sufficient.

Use the following graph to answer the questions below. Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates. -If we assume that carbon is the sole nutrient needed by sea slugs to drive their cellular respiration, then based on the graph, during which season(s)is it least necessary for P. ianthina to act as a chemoheterotroph?