Homework's 8-12

A complete digestive systems is a feature found in nematodes.

True

A respiratory systems is a feature found in nematodes.

False

Nematodes have a muscular systems of possessing longitudinal, diagonal and circular muscles under the tegument.

False

Copulatory spicules function to hold the female vulva open against hydrostatic pressure.

True

Two phyla that belong to the Ecdysozoan clade are Nematoda and Annelida.

False

The tracheal system has the advantage of preventing water loss but disadvantage of slower gas exchange.

False

Jointed appendages have the advantage of specialized function but at the cost of reduced locomotion.

False

Metamorphosis has the advantage of reducing competition within a species.

True

The exoskeleton of arthropods reduces dessication but has the disadvantage requiring ecdysis.

True

High metabolic rates are possible in arthropods due to greater intake of glucose.

False

Sea spiders belong to subphylum Chelicerata.

True

Members of the subclass Arachnida have a cephalothorax and abdomen.

True

Daddy longlegs are an arachnid.

True

A spider's food is partly digested externally and the nutritive juices are sucked into the stomach.

True

Millipedes belong to subphylum Diplopoda.

Flase

The generalized appendage of a crustacean has a distal portion that has a lateral endopod and a medial exopod.

False

Crayfish belong to order Crustacea.

False

The respiratory apparatus of a crayfish is

A set of gills under the carapace

The first pair of walking legs in a crayfish, lobster, crab, and their relatives, that is enlarged with a terminal claw is the

cheliped

Most appendages of crustaceans are biramous.

True

The correct order for layers of exoskeleton from outside to inside is epicuticle-endocuticle-exocuticle.

False

Molting and subsequent ecdysis in crustaceans is initiated by a stimulus perceived by the central nervous system.

True

The stages in the life cycle of a hemimetabolous insect are egg, nymph, and adult.

True

Division of labor is a disadvantage for social insects.

False

When insects have two pairs of wings, they are attached to the

Thorax with one pair on the mesothorax and one pair on the metathorax

In echinoderms, the coelom buds off from the archenteron.

True

In echinoderms, mesoderm derived cells line the entire coelom.

True

Brittle stars differ from sea stars by

-Having tube feet without suckers

-Lacking papulae, intestine, or an anus

-Lacking pedicellariae

-All of the choices are correct distinctions

-Having the ambulacral grooves closed and covered with arm ossicles

If you went to the ocean and brought back a sea star to keep in a marine aquarium, what would you feed it?

live clams

The function of the papulae in the sea star is digestion.

False

The tube feet of sea stars and sea urchins have actin and myosin in muscles in the five arms or "rays" that constrict the tube feet directly when stimulated by nerves from the sea star brain.

False

Tube feet run along the hemal groove that extends along the oral side from the mouth to the tip of each arm.

False

Pedicellariae are small pincer-like projections clustered on the skin of a sea star which serve to keep it clean of parasites and aquatic growth.

True

Water enters the water vascular system of a sea star through a porous plate on the aboral surface called the pedicellariae.

False

The orientation of a sea star is dorsal mouth and a ventral spiny surface facing upward.

False

Describe 3 of the 5 hallmark traits, explaining each trait.

1. Short Generation TimeA short generation time means the organism can reproduce quickly, allowing researchers to observe multiple generations rapidly. This is important for studying inheritance patterns, gene mutations, and evolutionary changes.

2. Large Number of OffspringModel organisms typically produce many offspring per mating. This provides a large sample size for statistical analysis of genetic crosses and increases the likelihood of observing rare genetic events.

3. Well-Annotated GenomeA well-annotated genome means the organism's DNA has been sequenced and its genes are well-mapped and studied. Researchers can easily identify, modify, or knock out specific genes.

Colonial sea squirts share an excurrent siphon.

True

Jawless fishes belong to subphylum cephalochordata.

False