Based on species numbers and ecological diversity, which lineage of protostomes is the most successful?
Arthropods
Select the correct statement about protostomes.
They are bilaterally symmetrical.
Which term describes an animal that lacks a body cavity?
Acoelomate
Which of the following statements correctly describes the arthropod exoskeleton?
The exoskeleton consists of layers of tough proteins interwoven by a stiff polysaccharide called chitin.
In addition to the lophophore, what are the two unique morphological traits that define lophotrochozoans?
Trochophore larvae and spiral cleavage
Which of the following statements about the phylogeny of protostomes is true, based on Figure 31.2? [[INSERT FIGURE 31.2]]
Rotifers are a basal group within the Lophotrochozoa.
Which of the following statements correctly describes a major adaptation in the water-to-land transition made by the following groups of animals?
Insects can close their respiratory passages.
What is a major line of evidence indicating multiple transitions to land in the Lophotrochozoa?
Annelid, flatworm, and mollusk lineages all include both aquatic and terrestrial members.
What key innovation allowed protostome animals to make precise and directed movements?
Jointed limb
Which reproductive innovations arose during protostome diversification?
Metamorphosis and a desiccation-resistant egg
The _____ is a structure that is used for feeding by sessile lophotrochozoans.
lophophore
Which group of mollusks feeds by siphoning water over the gills?
Bivalves
The bivalve shell is an adaptation that _____.
reduces predation
Molting involves _____.
shedding an external covering
Which of the following traits has helped to make arthropods so successful?
Metamorphosis
Which arthropod taxon has three body regions?
Insects
A group of three protostome animals includes one with trochophore larvae, one that molts, and one with a reduced coelom. Which statement most accurately describes this group?
The group includes both lophotrochozoans and ecdyzoans.
A school group is assigned to survey vast museum collections of all non-microscopic animals collected from various regions. Which observation is the group of students likely to make that sheds light on the reason for the success of protostomes?
The majority of the animals have wings.
If tetrapods had arisen 50 million years before they actually did, which of the following scenarios reflects the most predictable effect this change might have had on protostome evolution?
Protostome groups would exhibit less diversity in feeding structures and reproductive strategies.
Which of the following is the most reasonable assumption to make about an animal group that exhibits metamorphosis?
The juvenile and adult forms in this group eat different foods.