Chapter 32
Unlike plants, animals lack these rigid structures, allowing for greater flexibility.
What are cell walls?
This group includes animals that molt their cuticle, such as arthropods, and is a major division within protostomes.
What are ecdysozoans?
This type of free-living larva is a defining characteristic of Lophotrochozoa.
What is a trochophore?
This layer secreted by the mollusk's mantle may contain nacre and produce pearls.
What is the shell?
This phylum, exclusively found in marine environments, includes organisms such as sea stars and sea cucumbers.
What is Echinodermata?
This group of protostomes is characterized by spiral cleavage and growth by adding to their body mass rather than molting.
What are lophotrochozoans?
These two groups within deuterostomes share fewer phyla but are more uniform in structure despite their diversity.
What are chordates and echinoderms?
These ciliated tentacles surrounding the mouth are used by some Lophotrochozoa for filter-feeding.
What is a lophophore?
In mollusks, this structure is used for locomotion and may be divided into tentacles in some species
What is the foot?
The endoskeleton of echinoderms is composed of this substance, which can be tightly or loosely joined.
What is calcium carbonate?
Animals with this type of body symmetry can only be divided into two equal halves by the sagittal plane.
What is bilateral symmetry?
This type of symmetry is found in animals like cnidarians and allows for division into similar halves along any plane passing through the central axis.
What is radial symmetry?
This group of protostomes is characterized by spiral cleavage during embryonic development.
What are Lophotrochozoa?
This tonguelike structure in mollusks is used to scrape up algae but is absent in bivalves.
What is the radula?
chinoderms use this system, beginning with the madreporite, for movement, feeding, and gas exchange.
What is the water-vascular system?
This evolutionary feature in animals allows for independent movement and redundant organ systems within different segments.
What is segmentation?
This gelatinous layer in sponges contains structural elements like spicules and spongin.
What is the mesohyl?
The name "Lophotrochozoa" combines the Greek words "lopho" and "trocho." "Trocho" means this.
What is "wheel"?
These tiny bristles, made of chitin, assist in locomotion for many annelids.
What are chaetae?
Most echinoderms reproduce this way, with gametes released into the water for external fertilization.
What is sexual reproduction?
hese two animal groups were previously thought to be closely related due to their segmented body structures but are now placed in different clades.
What are annelids and arthropods?
Cnidarians use these specialized cells to capture prey, some of which contain venom.
What are nematocysts?
Arthropods in this group include insects and have a body divided into head, thorax, and abdomen.
What is Hexapoda?
This process, also called molting, is necessary for arthropods to grow due to their exoskeleton.
What is ecdysis?
These echinoderms, known for having five arms, are important predators in marine ecosystems.
What are sea stars?