BIOL1300 Systematics Lecture Notes

Flashcards covering key vocabulary terms and definitions from the lecture notes.

Lophotrochozoa

Major group within the animal kingdom belonging to the Bilateria.

Bilateria

Larger group within the Animalia; bilaterally symmetrical with a left and a right side.

Lophophore

A feeding structure consisting of a ciliated crown of tentacles surrounding a mouth, characteristic of Lophotrochozoa.

Trochophore larva

A distinct developmental stage of members of Trochozoa such as molluscs, platyhelminths and annelids though some may have none.

Protostomia

Includes Lophotrochozoa and Ecdysozoa. Flatworms, Molluscs, Annelids, Roundworms and Arthropods.

Deuterostomia

Includes Echinoderms and Chordates.

Platyhelminthes

Phylum of flatworms characterized by bilateral symmetry and lacking a body cavity (acoelomate).

Acoelomate

Lacking a body cavity (coelom).

Gastrovascular cavity

Incomplete digestive system in flatworms with one opening (mouth).

Cephalization

Evolutionary trend whereby nervous tissue becomes concentrated toward one end of an organism.

Protonephridia

Present in Platyhelminthes for osmoregulation and excretion of waste.

Flame bulbs/cells

Ciliated structures in protonephridia that draw water in and expel it out.

Nephridiopores

Excretory pore where water is expelled out.

Hermaphrodites

Organisms that possess both male and female reproductive organs.

Class Turbellaria

Includes marine worms & planarians, most are free living and not exclusively parasite.

Class Trematoda

Flukes; obligate internal parasites (endoparasites) which sucks blood or cell fluids.

Obligate internal parasites

Endoparasites that are parasites that sucks blood or cell fluids.

Schistosomiasis

Disease caused by the blood fluke Schistosoma.

Class Monogenea

Parasitic (most are ectoparasites) distinguished by the presence of haptor, a posterior attachment organ.

Haptor

A posterior attachment organ present in Monogenea.

Class Cestoda

Tapeworm; parasite with scolex, no mouth, and segmented body.

Scolex

Hooks, and suckers that attach to the intestinal wall (no mouth) of the tapeworm.

Proglottid

Segment containing reproductive organs.

Annelida

Phylum of segmented worms.

Serial homology

Condition in annelids where most internal and external parts are repeated with each segment.

Metanephridia

Excretory organs in annelids.

Prostomium and peristomium

Head is composed of a prostomium and peristomium.

Chaetae

Lateral, segmentally arranged epidermal bristles.

Clitellum

Unique reproductive structure is a ring of secretory cells in the epidermis that appears on the worm’s exterior.

Parapodia

Lateral appendages bearing tufts of many setae in errantia.

Phylum Mollusca

The second largest phylum and includes the snails and slugs, oysters and clams, and octopuses and squids.

Mantle

A fold of tissue that drapes over the visceral mass and secretes a shell (if one is present).

Mantle cavity

Water-filled chamber that houses the gills, anus, and excretory pores.

Hemocoel

Principal body cavity (open circulatory system).

Radula

Rasping organ usually present in mollusca.

Classes of Mollusks

Caudofoveata, Solenogastres, Polyplacophora, Monoplacophora, Scaphopoda, Gastropoda, Bivalvia, Cephalopoda.

Class Polyplacophora

Chitons; flattened with a convex dorsal surface bearing eight articulating calcareous plates.

Class Scaphopoda

Tusk shells or tooth shells, which are marine molluscs that have a slender tubular shell open at both ends.

Visceral mass and mantle

Rotate 90-180° on foot (a process known as torsion).

Class Bivalvia

Laterally compressed with typically of two valves hinged together dorsally by elastic ligament.

Class Cephalopoda

Head with large, complex eyes and circle of prehensile arms or tentacles around mouth.

Ecdysozoa

Characterized by a three-layered cuticle composed of organic material, which molts as the animal grows.

Ecdysis

The process of molting in ecdysozoans.

Phylum Nematoda

Roundworms; cylindrical body with tapered ends.

Pseudocoelom

False cavity; located between endoderm and mesoderm.

Amphids

Sensory organ at the anterior.

Phasmids

Sensory organ at the posterior.

Phylum Arthropoda

Jointed foot; largest phylum with insects, spiders, crustaceans, millipedes, scorpions, ticks, etc.

Tagma/tagmata

Regions with jointed appendages.

Ectoderm

Gives rise to the epidermis and nervous system.

Mesoderm

Gives rise to the muscles, connective tissues, and internal organs.

Endoderm

Gives rise to the lining of the digestive tract and associated organs.

Chelicerae

Clawlike feeding appendages in Chelicerata.

Pedipalps

Sensing or feeding appendages in Chelicerata.

Biramous appendages

Two main branches.

Subphylum Crustacea

Lobster, crayfish, shrimp, crab, water flea, barnacles.

Myriapoda

Two tagmata—head and trunk— with paired appendages on most or all trunk segments.

Hexapoda

Six legs present in its members All legs are uniramous.

Holometabolous

Complete metamorphosis.

Hemimetabolous

Gradual, or incomplete metamorphosis.

Amniotic egg

Structure that prevents water loss of embryo. Allows for eggs to be laid on dry land.

Ambulacraria

Echinoderms and Hemichordates that are the closest extant phylogenetic relatives of chordates.

Chordates

Bilaterally symmetrical animals with a coelom, three germ layers, segmented bodies, a complete digestive system, and a closed circulatory system.

Notochord

Skeletal structure present in all chordate embryos.

Hollow Nerve Cord

Develops from a plate of ectoderm that rolls into a neural tube located dorsal to the notochord which develops into the central nervous system.

Pharyngeal Slits or Clefts

Grooves or slits that open into the pharynx.

Muscular, Post-Anal Tail

Tail that extends posterior to the anus.

Pentaradial symmetry

the body parts extend from the center along five spokes.

Tube feet

Extensions of the water-vascular system.

Class Crinoidea

lily-like; Examples: sea lilies, feather stars with mouth facing up).

Class Ophiuroidea

Snake-tail; basket stars and brittle stars, which can regenerate easily.

Class Echinoidea

Spinelike; sea urchins, sand dollars with Aristotle’s Lantern.

Class Holothuroidea

Water polyp; sea cucumbers. Use tentacles to bring food to the mouth.

Class Asteroidea

Starlike; sea stars that can have 5 arms.

Chordata

All chordates possess a notochord & a dorsal, hollow, nerve cord, pharangeal slits and muscular post-anal tail

Agnatha

Jawless Fish that include Hagfish & Lampreys.

Scales

Protective outer layer.

Operculum

Bony flap allows water to be drawn over gills by fins.

Class Amphibia

First vertebrates to inhabit land with heart 3 chambered.

Reptilia

Lizards, snakes, turtles, and crocodilians, that can reproduce independently of water.

Aves

Birds; nearly all adaptations of these animals are made for flight.

Mammalia

Efficient mammalian Characteristics are they Have Hair, Endothermic & Mammary glands.