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A larva represents a distinct juvenile stage in the life cycle of many animals, preceding the adult form, and is particularly characteristic of species undergoing indirect development.
Answer: True
A larva constitutes a distinct juvenile morphological form within an animal's life cycle, preceding its transformation into the adult stage via metamorphosis. This developmental phase is notably prevalent in organisms exhibiting indirect development.
Larval forms typically exhibit significant morphological differences from the adult stage, rarely resembling the adult form closely except in size.
Answer: True
Larval forms typically exhibit significant morphological differences from the adult stage, often possessing unique structures and organs not found in adults, and may also differ considerably in diet.
Distinct larval environments can confer adaptive advantages, such as reduced competition with adults and decreased predator exposure.
Answer: True
Larvae can inhabit environments distinct from those of adults, providing adaptive advantages such as reduced competition for resources and enhanced protection from predators.
Mobile larval stages are crucial for dispersal, particularly for species where adults are sessile or have limited mobility.
Answer: True
For organisms with sessile adults, such as certain polychaetes or barnacles, mobile larval stages are critically important for dispersal, enabling the species to colonize new habitats.
Larval dispersal strategies primarily involve either planktotrophic feeding or reliance on endogenous yolk reserves (lecithotrophy).
Answer: True
Larval dispersal strategies are broadly categorized into planktotrophic, where larvae feed on plankton, and lecithotrophic, where larvae subsist on yolk reserves without external feeding.
Neoteny is defined as the retention of larval or juvenile morphological characteristics into adulthood, often accompanied by sexual maturity.
Answer: True
Neoteny refers to the retention of juvenile or larval morphological traits into sexual maturity. This phenomenon allows for reproduction without complete somatic development, as seen in certain amphibians.
The assumption that larval forms invariably reflect an animal group's deep evolutionary history is often inaccurate, as larval stages can evolve secondarily.
Answer: True
The assumption that larval forms invariably reflect an animal group's deep evolutionary history is often inaccurate. Larval stages can evolve secondarily, potentially diverging more from ancestral forms than the adult stage does, particularly evident in insects.
Which of the following best defines a larva in the context of animal life cycles?
Answer: A distinct juvenile form that undergoes metamorphosis into an adult.
A larva constitutes a distinct juvenile morphological form within an animal's life cycle, preceding its transformation into the adult stage via metamorphosis.
According to the source, how do larval appearances typically compare to adult forms?
Answer: Larvae often possess unique structures and significantly different appearances from adults.
Larval forms typically exhibit significant morphological differences from the adult stage, often possessing unique structures and organs not found in adults.
What advantage can distinct larval environments provide, as mentioned in the text?
Answer: Shelter from predators and reduced competition with adults.
Larvae can inhabit environments distinct from those of adults, providing adaptive advantages such as reduced competition for resources and enhanced protection from predators.
For immobile adult organisms like barnacles, what is the primary role of their mobile larval forms?
Answer: To facilitate dispersal to new locations.
For organisms with sessile adults, such as certain polychaetes or barnacles, mobile larval stages are critically important for dispersal, enabling the species to colonize new habitats.
Which of the following describes the lecithotrophic strategy of larval dispersal?
Answer: Larvae rely on stored yolk reserves and do not feed.
Larval dispersal strategies are broadly categorized into planktotrophic, where larvae feed on plankton, and lecithotrophic, where larvae subsist on yolk reserves without external feeding.
What is neoteny?
Answer: Reaching sexual maturity while retaining larval features.
Neoteny refers to the retention of juvenile or larval morphological traits into sexual maturity.
Which of the following statements about larval forms and evolutionary history is accurate according to the text?
Answer: A larval stage might have evolved later and differ more from the common ancestor than the adult form.
The assumption that larval forms invariably reflect an animal group's deep evolutionary history is often inaccurate. Larval stages can evolve secondarily, potentially diverging more from ancestral forms than the adult stage does.
The parenchymula, or stereogastrula, is a characteristic larval form observed in sponges belonging to the phylum Porifera.
Answer: True
Sponges (Porifera) exhibit larval forms such as the coeloblastula (also known as blastula or amphiblastula) and the parenchymula (also known as parenchymella or stereogastrula).
Cnidarians possess diverse larval stages, including the planula and actinula forms.
Answer: False
Cnidarians possess larval stages such as the planula (also termed stereogastrula) and the actinula. The statement implies only one type exists, which is false.
The miracidium represents a larval stage associated with Trematoda, a class within the phylum Platyhelminthes.
Answer: True
Platyhelminthes display diverse larval forms: Trematoda have miracidium, sporocyst, redia, and cercaria stages.
Annelids, or segmented worms, exhibit larval forms such as the nectochaete and polytroch.
Answer: True
Annelids, or segmented worms, possess larval forms known as nectochaete and polytroch.
The Dauer larva is a recognized developmental stage found within the life cycle of Nematodes.
Answer: True
Nematodes exhibit larval forms including the Dauer larva and the microfilaria.
The pelagosphera larva is the characteristic larval stage of Sipuncula (peanut worms), not Ectoprocta (moss animals).
Answer: True
The larval stage of Sipuncula, commonly known as peanut worms, is termed the pelagosphera larva.
The actinotroch is the specific larval stage identified for Phoronids.
Answer: True
The actinotroch is the characteristic larval stage of Phoronids.
Cycliophora larvae are known by various names, including the chordoid larva, but they do not exclusively use this single form.
Answer: True
Cycliophora possess larval forms known as pandora and chordoid larva, indicating multiple forms exist.
The pilidium is a distinctive larval form associated with Nemertea, commonly referred to as ribbon worms.
Answer: True
Nemertea, or ribbon worms, have larval forms including the pilidium, Iwata larva, and Desor larva.
The acanthor is the larval form of Acanthocephala (spiny-headed worms), not Brachiopoda (lamp shells).
Answer: True
The acanthor is the larval form of Acanthocephala, also known as spiny-headed worms.
Echinodermata larvae include diverse forms such as bipinnaria, pluteus, and auricularia.
Answer: True
Echinodermata exhibit several larval forms, including bipinnaria, vitellaria, brachiollaria, pluteus, ophiopluteus, echinopluteus, and auricularia.
The larval stage of sponges (Porifera) is indeed called a coeloblastula or amphiblastula.
Answer: True
Sponges (Porifera) exhibit larval forms such as the coeloblastula (also known as blastula or amphiblastula) and the parenchymula (also known as parenchymella or stereogastrula).
Platyhelminthes exhibit various larval forms, including cysticercus and oncosphere stages, particularly within the Cestoda and Trematoda.
Answer: True
Platyhelminthes display diverse larval forms: Trematoda have miracidium, sporocyst, redia, and cercaria; Cestoda have cysticercus, cysticercoid, oncosphere, coracidium, and plerocercoid.
The loricate larva is the characteristic larval form of Priapula, commonly known as penis worms.
Answer: True
The loricate larva is the characteristic larval form of Priapula, commonly referred to as penis worms.
The pluteus larva is associated with Echinodermata, not the phylum Cnidaria.
Answer: True
Echinodermata exhibit larval forms including the pluteus. Cnidarians typically have planula larvae.
The larval form known as 'parenchymula' or 'stereogastrula' is associated with which phylum?
Answer: Porifera
Sponges (Porifera) exhibit larval forms such as the parenchymula (also known as parenchymella or stereogastrula).
Which of these is a larval stage found in Cnidarians?
Answer: Planula
Cnidarians possess larval stages including the planula (also termed stereogastrula).
The larval forms 'miracidium' and 'cercaria' are associated with which group?
Answer: Trematoda (Platyhelminthes)
Platyhelminthes display diverse larval forms: Trematoda have miracidium, sporocyst, redia, and cercaria stages.
What are the two larval forms mentioned for Annelids (segmented worms)?
Answer: Nectochaete and Polytroch
Annelids, or segmented worms, possess larval forms known as nectochaete and polytroch.
Which of the following is a larval form found in Nematodes?
Answer: Dauer larva
Nematodes exhibit larval forms including the Dauer larva and the microfilaria.
The 'pelagosphera larva' is the larval stage of which group?
Answer: Sipuncula (peanut worms)
The larval stage of Sipuncula, commonly known as peanut worms, is termed the pelagosphera larva.
Which larval form is characteristic of Phoronids?
Answer: Actinotroch
The actinotroch is the characteristic larval stage of Phoronids.
Which of the following is a larval form associated with Echinodermata?
Answer: Auricularia
Echinodermata exhibit larval forms including the auricularia.
The trochophore larva is a larval form found in several phyla, including Molluscs, but it is not unique to them.
Answer: True
A shared larval form among certain Molluscs, Annelids, Nemerteans, and Sipunculids is the trochophore larva.
The veliger larva is a distinct larval stage found in some species of Mollusca, including certain Bivalvia (freshwater mussels).
Answer: True
Some molluscs possess a larval stage called the veliger larva.
The glochidium is the characteristic larval stage of freshwater mussels, which belong to the class Bivalvia.
Answer: True
Freshwater mussels, which are bivalves (a class of Mollusca), have a larval stage known as the glochidium.
Trilobite developmental stages included the protaspis, meraspis, and holaspis, representing distinct phases of growth.
Answer: True
Trilobites exhibited developmental stages including the protaspis (unjointed), meraspis (with an increasing number of joints but one less than the adult), and holaspis (which is the adult stage).
The euproöps larva, often termed a 'trilobite larva,' is the larval form characteristic of horseshoe crabs (Xiphosura).
Answer: True
The larval form of Xiphosura, also referred to as a 'trilobite larva,' is called the euproöps larva.
The protonymphon is the larval stage of Pycnogonida, commonly known as sea spiders.
Answer: True
The larval stage of Pycnogonida, commonly known as sea spiders, is known as the protonymphon.
The kentrogon is the larval form of Rhizocephala, a highly specialized parasitic crustacean.
Answer: True
The larval form of Rhizocephala, a highly specialized parasitic crustacean, is called the kentrogon.
The 'trochophore larva' is a shared larval form found in which of the following groups?
Answer: Molluscs, Annelids, Nemerteans, and Sipunculids
A shared larval form among certain Molluscs, Annelids, Nemerteans, and Sipunculids is the trochophore larva.
What is the specific larval stage of freshwater mussels (Bivalvia)?
Answer: Glochidium
Freshwater mussels, which are bivalves (a class of Mollusca), have a larval stage known as the glochidium.
Which larval stage is described as the adult stage for Trilobites?
Answer: Holaspis
The holaspis stage is considered the adult stage for Trilobites, following the protaspis and meraspis larval stages.
The larval form of Xiphosura (horseshoe crabs) is also known by what name?
Answer: Trilobite larva
The larval form of Xiphosura, also referred to as a 'trilobite larva,' is called the euproöps larva.
Which of the following is a general larval form found in crustaceans?
Answer: Nauplius
General larval forms found in crustaceans (a subphylum of Arthropoda) include nauplius, metanauplius, protozoea, and zoea.
The ammocoete is the larval stage of lampreys, not eels.
Answer: True
The specific larval form of lampreys (order Petromyzontiformes) is called the ammocoete.
Tadpoles and polliwogs are common vernacular terms for amphibian larvae.
Answer: True
Common terms used for amphibian larvae include tadpole and polliwog.
The dipleurula is a hypothetical larval form proposed for Deuterostomes, not Protostomes.
Answer: True
The hypothetical larval form proposed for Deuterostomes, a major clade of animals, is called the dipleurula.
The tornaria is the larval stage of Hemichordates, not Urochordates.
Answer: True
The larval form of Hemichordata, commonly known as acorn worms, is known as the tornaria.
The tadpole larva of Urochordates is considered a 'swimming embryo' because it is a mobile, non-feeding embryonic stage.
Answer: True
The larval stage of Urochordates (tunicates) is called a tadpole. It is sometimes considered a 'swimming embryo' because it does not feed and is essentially a mobile embryonic stage before metamorphosis.
Ichthyoplankton is the general term for fish larvae, not amphibian larvae.
Answer: True
The general term used for the larval stage of fish is ichthyoplankton.
The leptocephalus larva is characteristic of eels, not lampreys.
Answer: True
The larval form of eels (order Anguilliformes) is known as the leptocephalus.
The larval stage of lampreys is called the ammocoete.
Answer: True
The specific larval form of lampreys (order Petromyzontiformes) is called the ammocoete.
The 'dipleurula' is a hypothetical larval form proposed for which major group of animals?
Answer: Deuterostomes
The hypothetical larval form proposed for Deuterostomes, a major clade of animals, is called the dipleurula.
The 'tornaria' larva belongs to which group?
Answer: Hemichordata
The larval form of Hemichordata, commonly known as acorn worms, is known as the tornaria.
Why is the Urochordate larval stage sometimes called a 'swimming embryo'?
Answer: Because it does not feed and is essentially a mobile embryonic stage.
The larval stage of Urochordates (tunicates) is called a tadpole. It is sometimes considered a 'swimming embryo' because it does not feed and is essentially a mobile embryonic stage before metamorphosis.
What is the general term for fish larvae?
Answer: Ichthyoplankton
The general term used for the larval stage of fish is ichthyoplankton.
The 'ammocoete' is the larval form of which type of fish?
Answer: Lampreys (Petromyzontiformes)
The specific larval form of lampreys (order Petromyzontiformes) is called the ammocoete.
Which of the following are common terms for amphibian larvae?
Answer: Tadpole and Polliwog
Common terms used for amphibian larvae include tadpole and polliwog.
In certain eusocial Hymenoptera, the capacity to feed larvae is restricted to specific castes, such as female workers.
Answer: False
While female workers are primary feeders in many eusocial Hymenoptera, males can also participate in larval feeding in some species, though often less efficiently. Therefore, the restriction is not absolute.
Caterpillars are the larval forms of Lepidoptera (butterflies and moths), not beetles.
Answer: True
The larval form of Lepidoptera, which includes butterflies and moths, is commonly known as a caterpillar.
Maggots represent the larval form of flies, and also occur in some bees and wasps.
Answer: True
The larval form of flies (Diptera), and also some bees and wasps (Hymenoptera), is commonly called a maggot.
Endopterygotes are insect groups characterized by complete metamorphosis, which includes a distinct larval stage.
Answer: True
Insects belonging to the group Endopterygotes exhibit complete metamorphosis, which includes a distinct larval stage.
Apodous larvae are defined by their lack of legs and are typically poorly sclerotized.
Answer: True
Apodous larvae are characterized by having no legs and are poorly sclerotized (hardened). They are found in various insect groups.
Polypod larvae, also known as eruciform larvae, possess abdominal prolegs in addition to thoracic legs and are generally poorly sclerotized.
Answer: True
Polypod larvae, also known as eruciform larvae, possess abdominal prolegs in addition to the usual thoracic legs. They are generally poorly sclerotized, relatively inactive, and live in close proximity to their food source.
Scarabaeiform larvae are typically grub-like, poorly sclerotized, and inactive burrowers, not long-legged predators.
Answer: True
Scarabaeiform larvae are poorly sclerotized, with a flat thorax and abdomen, typically short-legged and inactive burrowing forms.
The larval form of the goldenrod gall fly is known as *Eurosta solidaginis*.
Answer: True
The image of an *Eurosta solidaginis* larva shows the larval stage of a goldenrod gall fly (Diptera).
The larval form of the Hercules beetle, *Dynastes hercules*, is renowned for its exceptionally large size.
Answer: True
The image shows the larva of the Hercules beetle, *Dynastes hercules* (Coleoptera), which is noted for being among the largest insect larvae.
Campodeiform larvae, such as those of *Micromus sp.*, are typically characterized by being well-sclerotized, active, and often predatory, not poorly sclerotized and inactive.
Answer: True
Campodeiform larvae are typically well-sclerotized, active, and often predatory, with long legs and prognathous mouthparts.
The larval form of flies, bees, and wasps is commonly called a maggot.
Answer: True
The larval form of flies (Diptera), and also some bees and wasps (Hymenoptera), is commonly called a maggot.
In species like the paper wasp *Ropalidia marginata*, who can potentially feed the larvae?
Answer: Both male and female workers, though females are more efficient.
While female workers are primary feeders in many eusocial Hymenoptera, males can also participate in larval feeding in some species, though often less efficiently. Therefore, the restriction is not absolute.
What is the common term for the larval form of Lepidoptera (butterflies and moths)?
Answer: Caterpillar
The larval form of Lepidoptera, which includes butterflies and moths, is commonly known as a caterpillar.
Which insect larva is typically referred to as a grub?
Answer: Larva of beetles
The larval form of beetles (order Coleoptera) is typically referred to as a grub.
What is the larval form of mosquitoes commonly called?
Answer: Wriggler
The larval form of mosquitoes (a type of fly) is known as a wriggler.
According to Antonio Berlese's classification, which type of insect larva has no legs and is poorly sclerotized?
Answer: Apodous larva
Apodous larvae are characterized by having no legs and are poorly sclerotized (hardened). They are found in various insect groups.
Which type of Oligopod larva is described as well-sclerotized, flattened, and often a predator?
Answer: Campodeiform
The two types of Oligopod larvae are Campodeiform (well-sclerotized, flattened, often predatory) and Scarabaeiform (poorly sclerotized, grub-like, inactive burrowers).
The larval form of the Hercules beetle, *Dynastes hercules*, is noted for being:
Answer: Among the largest insect larvae
The image shows the larva of the Hercules beetle, *Dynastes hercules* (Coleoptera), which is noted for being among the largest insect larvae.