Invert Zoology Test 3

What is a defining feature of organisms in the Cycloneuralia group?

They have an introvert, which can be everted or withdrawn.

What respiratory pigment is often found in the large fluid-filled cavity of some cycloneuralia?

Hemerythrin.

How is the trunk of a cycloneuralian organism described?

Superficially segmented externally, but not internally.

What type of feeding strategy do cycloneuralia organisms exhibit?

They can be predatory or detritivorous.

What is the form of reproduction commonly observed in cycloneuralia?

They exhibit separate sexes and spawning.

What is the characteristic larval form produced by cycloneuralia?

Lorica larvae.

What do Kynorrhynchia organisms have that is unique to their classification?

They are exclusively found in marine sediments and are less than one millimeter in length.

What is the primary distinction between lobopodia and arthropods?

Lobopodia have unjointed appendages, while arthropods have jointed appendages.

What is the common name for tardigrades, and what does it mean?

Water bears; 'tardigrade' means 'slow step' in Latin.

What ability do tardigrades have that allows them to survive extreme environments?

They can undergo cryptobiosis, a state of suspended animation.

What type of ecological habitats do tardigrades commonly inhabit?

Semi-aquatic habitats, such as mosses and lichens.

What unique feature do onychophorids (velvet worms) possess?

They have slime-producing oral papillae to capture prey.

What is the respiratory and circulatory status of tardigrades?

They lack specialized respiratory organs; gas exchange occurs via diffusion.

What is the difference between nephridia and Malpighian tubules?

Nephridia filter and reabsorb, while Malpighian tubules selectively secrete waste.

In what environment are onychophorids primarily found?

Tropical and humid environments.

What are the key physical characteristics of nematodes?

Nematodes are non-segmented, have a cuticle, possess a pseudocele under high pressure, and have a round cross-section.

How many nerve cords do nematodes have?

Nematodes have four nerve cords: one ventral, one dorsal, and two laterals.

What type of motion do nematodes utilize for movement?

Nematodes use a side-to-side whipping motion for movement due to their longitudinal muscles.

What kind of reproductive structures do nematodes possess?

Nematodes have discrete reproductive structures and are typically dioecious with sexual dimorphism.

What is the digestive system structure of nematodes?

Nematodes have a complete digestive system with regional specialization.

What distinct feature do nematodes possess that aids in their sensory functions?

Nematodes possess amphids, which are sensory structures located at the anterior end.

What is the significance of Trichinella spiralis?

Trichinella spiralis is a nematode that can cause illness in humans via undercooked pork.

What are some common human parasitic nematodes?

Common human parasitic nematodes include hookworms, pinworms, and heartworms.

What characterizes nematomorphs compared to nematodes?

Nematomorphs lack a functional digestive system as adults and have only one nerve cord.

What is the lifecycle of nematomorphs?

Nematomorphs have a juvenile stage that is parasitic on arthropods; they become free-living adults that reproduce in aquatic environments.

How do nematodes conduct gas exchange?

Nematodes perform gas exchange across their body surface due to their small size and thin body walls.

Describe the reproductive strategy of pinworms.

Pinworms lay eggs around the anal area at night, leading to easy transmission among children.

What is the relationship between Wuchereria bancrofti and elephantiasis?

Wuchereria bancrofti is a nematode that infects lymphatic systems, leading to the swelling characteristic of elephantiasis.

What is the ecological importance of nematodes?

Nematodes play significant roles in soil health and various ecosystems; many are free-living while some are parasitic.

What invertebrate group do priapulins belong to?

Priapulins are considered a group of blastocoelomate invertebrates, often referred to as penis worms.

What feature distinguishes priapulins from other worms?

Priapulins are unique in some species resembling a penis shape and are thought to possess a large body cavity filled with salomicides.

What is a defining feature of spoon worms in terms of their body structure?

Spoon worms have a proboscis structure that comes off anteriorly and is used for feeding.

In which form do spoon worms show signs of segmentation?

Signs of segmentation are only apparent during larval development.

What is a consequence of the arrangement of the anus and tentacles in spoon worms?

The anus is positioned to prevent fouling of the tube they inhabit.

What unique reproductive characteristic do some species of spoon worms exhibit?

Males are greatly reduced in size, demonstrating sexual dichomorphism.

What is the significance of the ciliated urns in the body of spoon worms?

Ciliated urns help in waste removal by collecting dead and damaged cells.

What unifying feature characterizes the group Ectisozoa?

All members of Ectisozoa have a cuticle that is shed, a process known as ecdysis.

What is the primary purpose of ecdysis in Ectisozoa?

Ecdysis allows for the shedding of the old cuticle and the growth of a new one.

Which organism is a model organism widely used in developmental studies?

C. elegans (Caenorhabditis elegans) is a widely used model organism.

What type of muscle arrangement do nematodes possess?

Nematodes only have longitudinal muscles, lacking circular muscles.

How do nematodes primarily move through their environment?

Nematodes move by contracting longitudinal muscles in a whip-like motion.

What are amphids in nematodes?

Amphids are chemosensory structures located anteriorly on the head of nematodes.

How does the cuticle structure of nematodes compare to that of arthropods?

Nematodes' cuticle is made of collagen, while arthropods have a chitin-based exoskeleton.

What is a common habitat for nematodes?

Nematodes are found in various habitats including soil, freshwater, marine environments, and within plants.

What type of symmetry do nematodes exhibit?

Nematodes exhibit bilateral symmetry.

Which phylum do nematodes belong to?

Nematodes belong to the phylum Nematoda.

What is unique about the development of C. elegans?

C. elegans has a fixed number of cells and a well-mapped developmental pathway.

What adaptation helps nematodes prevent internal damage due to their high-pressure environment?

Nematodes possess a muscular pharynx to push food into their bodies, aided by their high internal pressure.

What is the basic ability of annelids when it comes to appendages?

Annelids have the ability to regenerate lost appendages, such as parapodia and tail ends, but not the head.

Which segment of an annelid can regenerate the tail?

Only the anterior most segment is capable of regenerating the tail.

What type of reproduction is rare among annelids?

Asexual reproduction is rare among annelids.

What is transverse partitioning in annelids?

Transverse partitioning refers to a form of reproduction where segments of the annelid undergo autonomy to form clones that may detach.

What are dioecious organisms?

Dioecious organisms have separate sexes.

Where do gametes develop in most annelids?

Gametes develop in the coelomic cavity rather than in distinct gonads.

How are gametes released in marine annelids?

Gametes are released through nephritic pores or ruptured body walls.

What type of larva do annelids produce after fertilization?

They produce a trochophore larva, which is a planktonic larva.

What is the function of the trophosome in giant tube worms?

The trophosome is a specialized organ containing symbiotic bacteria that enable chemosynthesis.

What role do environmental cues play in the reproductive strategy of epitokes?

Environmental cues trigger atokes to transform into reproductive epitokes, which then swim to the surface for spawning.

What is a unique characteristic of the hemoglobin in giant tube worms?

Their hemoglobin can bind both oxygen and hydrogen sulfide, allowing them to survive in toxic environments.

What are zombie worms and what is their ecological role?

Zombie worms consume the bones of large marine animals, playing a critical role in decomposing and recycling nutrients.

What distinguishes leeches from other annelids in terms of reproduction?

Leeches are hermaphrodites with permanent gonads, capable of reciprocal sperm exchange.

What is the significance of a clitellum in earthworms?

The clitellum secretes a cocoon for fertilized eggs during reproduction.

How do leeches prevent blood pooling during their feeding process?

Leeches inject anticoagulants into their prey to keep blood flowing.

What is the life cycle of the palolo worm known for?

The palolo worm is known for its massive swarming reproductive events tied to lunar cycles.

What adaptations do echiuran worms have for feeding?

Echiuran worms have a ciliated proboscis used for collecting organic material from their environment.

What is a ganglion?

A collection of cell bodies of neural tissue acting as a coordinating center.

Where are dorsal ganglia typically located in organisms?

Dorsally, with ventrally running nerve cords.

What does 'circumenteric' mean in the context of connectives?

Connectives that circle the digestive system.

What are the two major classes of Annelids mentioned?

Polychaetes and Clitellata.

What feature distinguishes Clitellata?

The presence of a clitellum.

How do sensory structures differ between Errantians and sedentary Annelids?

Errantians tend to have more well-developed sensory structures due to their mobility, while sedentary forms have reduced sensory structures.

What are parapodia?

Fleshy appendages used for locomotion and gas exchange in some Annelid species.

What is the significance of the nouveau organs?

Chemosensory structures found exclusively in certain Annelids.

How do spaghetti worms feed?

They extend their tentacles across the surface to capture organic material and transport it back to their mouth.

What is a distinguishing feature of the bloodworm?

It has a highly developed proboscis with fang-like structures for capturing prey.

What distinguishes organisms with complete digestive systems from those with gastrovascular cavities?

Complete digestive systems allow for regional specialization and continuous eating, unlike gastrovascular cavities where all processes occur in one large space.

What are the primary regions of the complete digestive system?

Foregut, midgut, and hindgut.

What is the function of the hindgut in a digestive system?

The hindgut is primarily responsible for absorption of nutrients.

Define deposit feeders.

Deposit feeders are organisms that ingest sediment or substrate to extract organic material.

What role does the muscular pharynx play in deposit feeders?

The muscular pharynx helps to grind up sediment for better digestion and assimilation.

What is the function of the crop in many organisms?

The crop stores material until it is ready to be processed further.

Describe the structure and function of an earthworm's gizzard.

The gizzard is a muscular structure that physically breaks down food into smaller particles for digestion.

How does the circulatory system of annelids differ from that of vertebrates?

Annelids often have a closed circulatory system with large dorsal blood vessels, and many lack red blood cells.

What is hemoglobin and how does it differ in earthworms?

Hemoglobin is the oxygen-carrying protein, but in earthworms, it is large with many binding sites, unlike vertebrate hemoglobin.

What is the difference between evaginations and invaginations in respiratory structures?

Evaginations protrude outward (like gills), while invaginations extend inward (like lungs).

What is the function of metanephridia in annelids?

Metanephridia are osmoregulatory structures that filter body fluids to maintain water and ion balance.

How do annelids achieve nutrient absorption in their intestines?

They increase surface area with folds, villi, and microvilli to enhance nutrient transport across membranes.

Why do fish suffocate when taken out of water despite having oxygen in the air?

Fish gills collapse out of water, reducing surface area for gas exchange.

What adaptations do some annelids have for surviving in extreme environments, like hydrothermal vents?

They modify their respiratory structures and can withstand high temperatures and other extreme conditions.

What is the Indo-Pacific known for in terms of marine diversity?

The Indo-Pacific has massive diversity in cephalopods, fish, corals, and other invertebrates, being the oldest part of the ocean.

How do cephalopods with thicker mantles move?

They rely on muscularity of the mantle for movement, utilizing jet propulsion.

What is the relationship between cephalopods like squid and octopuses in terms of swimming habits?

Squid are constantly swimming in the water column, whereas octopuses and cuttlefish prefer to crawl on the bottom.

How do squid and cuttlefish utilize their body structure?

Squid have long tentacles and arms; cuttlefish have a more pronounced shell structure.

What adaptation do octopuses have regarding their activity patterns?

Most octopuses are nocturnal and less active during the day.

What is the significance of chromatophores in cephalopods?

Chromatophores allow cephalopods to change color and patterns for camouflage.

What unique behavior is exhibited by the coconut octopus?

It carries coconut shells to use as shelter and hides from predators.

What is the difference between dioecious and monoecious organisms in terms of sex?

Dioecious organisms have separate sexes, while monoecious organisms have both male and female reproductive structures.

How do female octopuses care for their young?

Females often guard and care for their eggs, not feeding until the young hatch, after which they typically die.

What role does hydrostatic pressure play in annelids?

Hydrostatic pressure provides structure and assists in locomotion by allowing localized deformations of the body.

What are metamerism and its significance in annelids?

Metamerism refers to the serial repetition of segments which allows for localized control and independent function within body segments.