Upgrade to remove ads
BIO 101 Exam #2 Prep Arthropods
Terms in this set (26)
pincer-like first pair of legs in crustaceans, used for seizing and crushing
pair of head appendages on members of Chelicerata (including arachnids)
second pair of appendages in arachnids
shell-like plate (calcified chitin) covering the cepahlothorax of some crustaceans
compound body segments of arthropods formed through the fusion of two or more segments (e.g., head, thorax, abdomen)
respiratory openings along the sides of abdominal segments
What feature(s) make arthropods ecdysozoan protostome bilaterian animals?
Arthropods are ecdysozoans in that they have an outer, non-cellular cuticle layer that is shed (except in Nematoda). Arthropods are protostomes in that the blastopore (first opening) develops into the mouth, the nerve cord is ventral, and the developing embryo divides with spiral cleavage. Arthropods are bilaterians in that they are bilaterally symmetrical, have triploblastic tissues, and are cephalized (nervous structures concentrate in a head region). Arthropods are animals in that they are multicellular heterotrophs that gain nutrition through ingestion.
List the synapomorphies for Arthropoda
chitinous exoskeleton (shed); jointed (articulated) appendages; compound eyes; segmented bodies
List the synapomorphies for Chelicerata
two tagmata (cephalothorax and abdomen); chelicerae (first pair of appendages developed as "fangs")
List the synapomorphies for Myriapoda
one pair of antennae; loss of compound eyes; two tagmata (head and trunk)
List the synapomorphies for Crustacea
compound eyes on stalks; two pairs of antennae; biramous appendages; two tagmata (cephalothorax and abdomen)
List the synapomorphies for Hexapoda
three pairs of uniramous legs; abdominal legs lost; three tagmata (head, thorax, and abdomen); two pairs of wings
How do the tagmata differ among different arthropod groups?
Tagmata are the segmented, functional body parts of arthropods. Myriapods, chelicerates, and crustaceans have two tagmata (head and trunk in myriapods; cephalothorax and abdomen in crustaceans and chelicerates). Hexapods have three tagmata (head, thorax, and abdomen).
What does it mean for an arthropod to be "biramous" or "uniramous", and which arthropod groups are characterized by each term?
"Biramous" refers to appendages that have two branches
"uniramous" appendages have only a single branch (unbranched).
Crustaceans are biramous, and all others are uniramous.
Distinguish between different myriapod clades.
Chilopods (centipedes) have one pair of legs per trunk segment
Diplopods (millipedes) have two legs per trunk segment.
How do myriapods differ from other arthropod clades?
Myriapods have two tagmata (head and trunk) and they lack compound eyes (secondarily lost).
How might you tell the difference between a chilopod centipede and a polychaete annelid?
Chilopod arthropods (centipedes) and polychaete annelids look superficially similar because they both have elongate, segmented bodies.
Chilopods have a chitinous exoskeleton (absent in annelids) and jointed appendages (polychaetes have parapodia with setae that look like appendages).
What is the advantage of ecdysis (molting) in arthropods such as crustaceans?
Molting is initiated hormonally when inhibiting hormones are decreased and molting hormones are increased. During the pre-molt phase, the old cuticle thins and separates from the epidermis. Ecdysis itself occurs when the cuticle ruptures and the animal "backs out" of its old exoskeleton. In the post-molt phase, the new cuticle stretches and thickens
What is the most diverse clade of Hexapoda called?
Distinguish between complete and incomplete metamorphosis in hexapods.
Incomplete metamorphosis-gradual transition from larvae to adults with an intermediate nymph stage
Complete metamorphosis- the larva develops dramatically within a chrysalis (pupa) before emerging as an adult. (No nymph stage)
Distinguish the wings of Lepidoptera (one of major clades of hexapods)
butterflies and moths with two pairs of large, scale-covered wings
Distinguish the wings of Coleoptera (one of major clades of hexapods)
beetles with two pairs of wings, forewings covered by protective shell (elytra)
Distinguish the wings of Hymenoptera (one of major clades of hexapods)
ants and bees with two pairs of membranous wings
Distinguish the wings of Diptera (one of major clades of hexapods)
true flies with one pair of wings (hindwings modified as halteres)
Would you consider crustaceans to be predatory, suspension feeders, parasites, or any combination of those?
predatory (malacostracans= crabs)
suspension feeders (maxillopods= barnacles)
parasitic (maxillopods= fish lice)
How does the cuticle differ between crustaceans and all other arthropods?
The cuticle of all arthropods is composed of chitin
the cuticle in crustaceans is calcified to form a carapace.
You might also like...
SDSU Ekdale Bio101 Test 2 #2 Spring'16
Other sets by this creator
BIO EXAM 2 Terms
BIO 101 Exam #2 Prep Mollusks, Segmented Worms, &…
BIO 101 Exam #2 Prep Cnidarians and Flatworms