Exam 5 Material (Annelids: Group of Lophotrochozoans: Part 2)

Question 1

What group is being described?:
- about 80,000 species—most of them are decomposers and live in soil—they’re exceedingly numerous—have a pseudocoelom (is filled w/ fluid that forms a hydrostatic skeleton—provides rigidity for muscles to contract against)—they have a tough and flexible cuticle—are pointed at both ends (w/o a very distinct head)—have a complete digestive tract—the males are generally smaller than the females/typically have separate male and females (nematodes are not homophoridic)—probably NOT a monophyletic group—their simplified body is maybe something that evolved from more complex ancestors—so nematodes are not decomposers but are parasitic

Answer 1

Nematoda (round worms)

Question 2

What group is being described?:
- about 80% of all known animals are anthropods—they are segmented—have a hard exoskeleton (made of chitin—must molt it when they outgrow it—it serves for protection and support—exodermal skeleton to where muscles attach—helps w/ water retention)—have paired/jointed appendages (serve many different purposes)—their nervous system is similar to annelids (simple ganglia/ventrally located nerve cord)—have a variety of affective sensory organs (including antennae and compound eyes)—have an open circulatory system (aren’t blood vessels sending hemolymph to all of the different structures but organs bathed by hemolymph)—have gills when they’re aquatic and have tracheal tubes or book lungs when they live on land

Answer 2

Arthropoda (includes insects and crustaceans)

Question 3

Which group is being described?:
- we see legs and claws, but legs are not jointed, jaws are derived from their appendages)

Answer 3

Onychopharans

Question 4

Which group is being described?:
- they are tiny, have short and unjointed legs (8), can live in various conditions

Answer 4

tardigrades

Question 5

Which type of Arthropoda is being described?:
- are the “arthropods plus”—we see segmentation/legs and claws

Answer 5

patharthropoda

Question 6

Which type of Anthropoda is being described?:
- means “many feet”—have many segments—have between 1 and 2 uniramous (one single end) legs per segment

Answer 6

Myriapoda

Question 7

Which type of Anthropoda is being described?:
- only have two segments (the cephalothorax: fused head and thorax and the abdomen)—only anthropoid w/ no anttenae—their first two pair of appendages are the fang-like CHILISORAE and the PEDIPELTS (have numerous ways they are used)—the remaining four pairs of appendages are used for walking (walking legs)—have book lungs (books gills for horseshoe crabs)

Answer 7

Chelicerate (horseshoe crabs/arachnids: spiders, scorpions, ticks, mites)

Question 8

Which group is being described?:
- are primarily aquatic (live in the water though there are some land crabs)—have a nonporous larva—have biradius appendages (end at two points)—their mandibles (third pair of appendages—used for biting/grinding food)—their first two pair of appendages are the antennae (for touch and taste)—behind the mandibles, there are two pairs of maxillae (they have modified appendages that can be used by males to transport sperm)

Answer 8

Crustacea (lobsters, crabs, shrimp, isopods, barnacles, and copepods)

Question 9

What makes barnacles special?

Answer 9

They are the only sessile crustaceans

Question 10

Which group is being described?:
- have about 10,000 species (lobsters, crayfish)—have four pairs of walking legs but anteriorly have a pair of chelipeds (used for various functions—fighting, getting food)—they have swimmerets (used for swimming/holding eggs—first pair of swimmerets can be used by males for copulation—can insert into female and deposit sperm)—have three distinct segments (cephalothorax—head, thorax, abdomen)

Answer 10

Dectopoda

Question 11

Which group is being described?:
- means “six legs”—over 1 million species—most successful animal group on the planet—not necessarily a monophyletic group (might be sister taxa to crustacea though)—insect legs are articulated/tracheated (have spiracles)—three distinct body segments—b/c of exoskeletons, they have to go through several molts as they grow—have uniramous appendages (doesn’t end in two tips)—have one pair of antennae—they have wings (not every insect has wings though)—most insects have complete metamorphosis

Answer 11

Hexapods (bees, ants, grasshoppers, roaches, flies, beetles)