Post-Midterm Pt 2 Flashcards
What mouth parts/antennae do Crustaceans have?
2 pair antennae (1st uniramous, 2nd biramous), 1 pair mandibles, 2 pair maxillae
Describe the crustacean larva
Called “nauplius”, have 3 sets of limbs (all for swimming) - 1st antennae, 2nd (biramous) antennae, and a biramous “mandible” which becomes the mandible in the adult
The thoracic appendages of crustaceans are called ______
Periopods
The abdominal appendages of crustaceans are called _____. What is their function?
“Pleopods”. Can help in swimming but may be modified in males for sex. May hold eggs in females.
What is unique about the anterior thoracic limbs of crustaceans?
May be modified as claw-bearing structures
Describe the life cycle of the anchor worm, “Lernea”
Starts as nauplius larva, burrows into fish. There it grows “anchors” (basically little hooks) off the cephalothorax and the abdomen elongates, and mouth and gut disappear
Describe the basic features of the chelicerata
Includes spiders, scorpions. Have no antennae, mandibles, or maxillae. Instead have two pairs of head appendages called chelicerae and pedipalps. Usually have 4 pairs of locomotory appendages.
How are the bodies of chelicerates divided? How do these differ from others?
Into Prosoma - cephalothorax and opisthosoma - posterior behind cephalothorax. Opisthosoma includes respiratory organs and heart as well.
_____ are mites that burrow into human skin, causing inflammation and turning the skin red
Scabies
In scorpions, the claws are formed by _____
The first pair of walking legs
When chelicerates feed, they engage in pre-oral digestion. What is this?
Occurs when chelicerates inject prey with digestive enzymes so they can drink the body contents
Describe the basic insect body structure
Divided into head, thorax, and abdomen.
Head has 6 segments with 1 pair mandibles, 1 pair antennae, 1 pair maxillae.
Thorax has three segments, prothorax, mesothorax, and metathorax. Each bears 1 pair legs.
Abdomen has 11 segments
Wings of insects are found on the _____ and _____
Mesothorax and metathorax
What is the primary function of the insect abdomen
Reproduction. Egg storage and such
Moths and butterflies are of the order _____
Lepidoptera
What is unique about cicadas
Live underground for years, randomly emerge in swarms of thousands.
Have no predators because nothing can adhere to their weird schedules
What is the common name of the order Coleoptera? What makes them unique
Beetles. Forewings form a hard shell called the “elytra” that protects the hind wings
The bees, wasps, and ants belong to order _____
Hymenoptera
Describe insect order Diptera
True flies with only 1 pair flying wings
The dragonflies are in order ____
Odonata
What does the word “echinoderm” mean?
Spiny skin
Briefly describe class Stelleroidea of the Echinoderms
Contains the Asteroidea (sea stars) and the ophiuroidea (brittle stars).
Describe the Asteroidea
Sea stars. Have a large coelomic cavity that extends into the arms, with open ambulacral grooves on the oral surface
Describe the Ophiuroidea
Includes brittle stars (ex. Gorgonocephalus). Arms set off from a central disk, have no ambulacral grooves, arms filled with calcified ossicles (very thin with no water-vascular system)
Describe the Crinoidea
Includes the sea lilies and feather stars. Have branched arms with pinnules to increase surface area for feeding. Unlike the Stelleroidea, the Crinoidea’s oral side is directed upwards. They appear in both stalked and free moving forms
Describe the Echinoidea
Includes sea urchins, sand dollars, Heart urchins.
They have no arms, are slightly spherical or dorso-ventrally flattened. Ossicles are fused to form a solid skeleton (called test)
Describe the Holothuroidea
Body elongated along oral-aboral axis. Are kind of cylindrical, may be slightly flattened in cross section. Skeleton is reduced to microscopic ossicles.
The Echinoderms are the only invertebrates that are _____. What does this mean?
Deuterostomes. Embryologic blastopore becomes the anus
What Echinoderm trait makes them more similar to Vertebrates than other Inertebrates? What does this mean?
Echinoderms are deuterostomes (just like all vertebrates). Embryologic blastopore becomes the anus
Describe the basic characteristics of the Echinoderms
Exhibit pentaradial symmetry, with the body arranged in 5 parts around a central axis. Have an endoskeleton of calcareous ossicles in body wall. Have spines or tubercles projecting through the epidermis.
Most have a water-vascular system. There is no cephalization and they are divided into oral (mouth bearing) and aboral surfaces.
Describe the skeleton of the Echinoderms
Have an endoskeleton of calcareous ossicles in body wall, which can link together to form a flexible skeleton or fuse to form a rigid “test” (is reduced to be microscopic in Holoturoidea). Have spines or tubercles projecting through the epidermis.
What makes the Crinoidea unique when compared to other Echinoderms?
Oral surface is dorsal instead of ventral
Describe the water vascular system of Echinoderms
Internal, closed system filled with water. Internal surface is ciliated and water enters through madreporite. The stone canal leads from the madreporite to the circular duct around the mouth, which splits off into radial vessels (1 through each arm). Tentacle-like outpocketings called “tube feet” protrude from the skin.
What is the purpose and structure of Echinoderm tube feet? How do they move?
Suckered feet adhere to substrate and may function in movement, seizing/holding prey, passing food to mouth, and as respiratory organs.
They move by contracting a reservoir (“ampulla”) above the foot to generate hydrostatic pressure
What are the two portions of the Enterocoel of the Echinoderms
Perivisceral coelom - Around viscera
Hydrocoel coelom - Forms water vascular system (distinct from perivisceral)
Describe the digestive system of Echinoderms
Begins at mouth, ends at anus, lined by endoderm. Lateral evaginations close to the anus form digestive glands that may also store food. The anus removes very little waste, as most excretion is performed by the papillae and tube feet
What is unique about the digestive system of the Asteroidea
Many digest food outside the body, extracellularly. Thus, no waste and very little need for digestion
What is unique about the feeding method of the class Echinus
Feed using a structure called “Aristotle’s Lantern”. It is an apparatus used to scrape rocks and other substrates. Consists of 5 teeth operated by muscles, and can be protruded slightly when in use
How do varying Echinoderm classes respirate?
The Stelleroidea respirate using dermal papillae (skin gills), Holothuroidea take in air through their cloaca (which then enters the respiratory tree), and Echinoidea use tube feet
Describe the nervous system of Echinoderms
Divided into one or more nerve rings surrounding the mouth. These give off radial nerves into the arms (similar to water-vascular system)
Describe reproduction in Echinoderms
Most have 2 sexes and external fertilization. Usually have 10 gonads (2 per arm), each in a genital sac. Each gonad has a duct connected to a gonopore which opens near the base of arms or, where no arms are present, between ambulacral zones. Gametes are shed seasonally
Describe fertilization in Echinoderms
Eggs are very small and surrounded by a jelly-coat. The sperm are flagellated, and the fusion of the two produces a diploid zygote. Eggs stick to substrate using their viscous covering.
Sea star larvae are called _____
“Brachiolaria”
Describe the mutable connective tissue of Echinoderms. Give examples of how different Echinoderms do this
Echinoderms can change the consistency of their connective tissue to an almost liquid form. This results from changing the polymerization of collagenous tissue in the dermis (by changing concentration of Ca++ ions).
Sea urchins stiffen dermis to anchor spines so they can lodge in a crevice or scare off predators.
Sea stars stiffen dermis to provide a scaffold against which they can pry bivalves open.
