BIOL 1114 Studying (species identification/tree of life)

Cnidaria

Tubular, diploblastic animals with radial symmetry, polyp & medusa forms, cnidocytes (stinging cells), and a nerve net throughout the body

Scyphozoa

Class of Cnidaria (jellyfish); medusa-dominant; manubrium for food capture; rhopalium sense organs; separate sexes; strobilation for asexual reproduction

Cubozoa

Class of Cnidaria (box jellyfish); very deadly

Hydrozoa

Class of Cnidaria; colonial, polyp-dominant; sexual reproduction in medusa stage; gastrozooids for feeding, gonozooids for reproduction

Anthozoa

Class of Cnidaria; no medusa stage; includes anemones, corals, sea fans; siphonoglyph moves water into cavity; attach via pedal disc; have nematocysts and acontia

Ctenophora

Comb jellies; no nematocysts; ctenes for movement; colloblasts (2 sticky tentacles) for food capture; apical sense organ; first complete gut in animal evolution; hermaphroditic

Coral bleaching

Caused by loss of zooxanthellae; 5 mass bleaching events since 1988

Lophotrochozoa

Animals with either a lophophore (crown of ciliated tentacles) or a trochophore larval stage

Platyhelminthes

Flatworms; mostly parasitic; organ-level organization; bilateral symmetry with cephalization; ladder-type nervous system with 2 main nerve cords

Turbellaria

Free-living, non-parasitic freshwater flatworms; have chemoreceptors and eyespots; 3 muscle layers; asexual and hermaphroditic

Trematoda

Parasitic flukes; well-developed reproductive system; hermaphroditic

Cestoda

Tapeworms; scolex attaches to host intestinal wall; body made of proglottids, each with male and female reproductive organs; can self-fertilize

Rotifera

Free-living pseudocoelomates with lophophore-like feeding device; parthenogenesis default; switch to sexual reproduction under stress; sexual reproduction produces diploid resting eggs

Annelida

Segmented worms; metamerism; septa divide fluid-filled coelom acting as hydrostatic skeleton; chaetae (bristles) for movement

Polychaeta

Marine annelids; errantia are predators with long chaetae, developed eyes, and powerful jaws; sedentaria anchor to burrows with chaetae close to body wall

Oligochaeta

Earthworms; hermaphroditic

Hirudinea

Leeches; 2 suckers (one on each end); secrete hirudin to prevent clotting

Siboglinids

Annelids living near hydrothermal vents; gut tissue forms trophosome with bacteria for nutrient conversion

Mollusca

Soft-bodied animals with 3-part body plan (visceral mass, mantle, head-foot); open circulation

Visceral mass

Mollusca body part that contains the internal organs

Mantle

Mollusca body part that secretes the shell and helps develop gills or lungs

Head-foot

Mollusca body part; muscular structure for movement, food capture, and sensory reception

Bivalvia

Molluscs (clams, oysters, mussels); two hinged shells; separate sexes; filter feeders

Gastropoda

Molluscs (snails, slugs, nudibranchs); mantle functions as lungs in land species, gills in aquatic species

Cephalopoda

Most advanced molluscs (Nautilus, cuttlefish, squid, octopus); head-footed; jet propulsion via mantle cavity; only mollusks with closed circulation; spermatophores transferred male to female

Ecdysozoa

Animals that undergo ecdysis (molting); some with metamorphosis; internal fertilization allows reproduction in dry environments

Nematoda

Roundworms; habitat/host specific; most are predators or saprophytes; eutely (fixed cell number at maturity); only longitudinal muscles

Eutely

Characteristic of nematodes where all mature individuals of a species have the same number of body cells

Hookworms

Nematode parasite; penetrate skin → heart → lungs → up trachea → swallowed → mature in intestine → eggs passed in feces

Arthropoda

Most speciose phylum; segmented body with fused regions (tagmata); setae for sensory/locomotion; complete digestive system with 2-part stomach and gastric mill

Crustacea

Arthropods with thorax bearing 5 pairs of legs; first pair = chelipeds; head and thorax fused into cephalothorax

Chelicerata

Arthropods (spiders, scorpions, ticks, horseshoe crabs); all appendages on cephalothorax; first pair = chelicerae, second = pedipalps; no antennae

Uniramia

Arthropods with uniramous (single-branch) appendages; use tracheae to breathe; largely terrestrial

Hexapoda

Insects; 3 pairs of legs; undergo metamorphosis

Ametabolous

Type of insect development with no metamorphosis; organism just grows larger (e.g. silverfish)

Hemimetabolous

Gradual/incomplete metamorphosis; nymph stage before adult (e.g. dragonflies, grasshoppers)

Holometabolous

Complete metamorphosis in most insects; egg → larva → pupa → adult (e.g. butterflies, beetles)

Myriapoda

Uniramians including centipedes (chilopods) and millipedes (diplopods)

Chilopoda

Centipedes; flat body; fast and carnivorous; have poison glands

Diplopoda

Millipedes; rounded body; slow-moving deposit feeders on decaying matter

Deuterostomia

Animals with radial indeterminate cleavage; blastopore becomes the anus; eucoelomates; coelom forms by enterocoely

Echinodermata

Marine animals (starfish, sea urchins, sea cucumbers); bilateral as larvae, radial as adults; mutable connective tissue; water vascular system; no cephalization (nerve ring instead)

Water vascular system

Echinoderm system using water for movement, feeding, and gas exchange; pathway: madreporite → stone canal → ring canal → 5 radial canals → lateral canals → ampulla → tube foot

Pedicellariae

Pincer-like structures made of ossicles on echinoderms; function to protect and clean the organism

Dermal branchiae

Projections of the coelomic cavity in echinoderms; serve as respiratory and excretory structures

Chordata

Animals with 5 key features at some point in development: notochord, dorsal hollow nerve cord, pharyngeal pouches, post-anal tail, and endostyle/thyroid gland

Notochord

Chordate feature; flexible supporting rod

Pharyngeal pouches

Chordate feature (gill slits); used for filter feeding or respiration

Post-anal tail

Chordate feature that evolved for water propulsion

Endostyle / Thyroid gland

Chordate feature; secretes iodinated hormones

Cephalochordata

Lancelets; fish-like marine invertebrates; no backbone but retain notochord and nerve cord along entire body; all 5 chordate characteristics throughout life

Urochordata

Tunicates and sea squirts; sessile filter feeders; only retain gill slits and endostyle as adults; exhibit paedomorphosis

Paedomorphosis

Retention of juvenile or larval traits of an ancestor in the adult form of a descendant

Vertebrata

Chordates with vertebral column, cranium, endoskeleton, GI tract, closed circulation, endocrine system, and multiple Hox gene clusters

Cyclostomata

Jawless vertebrates; hagfishes (no jaws, eyes, fins, or vertebrae) and lampreys (no scales; parasitic with sucker-like oral disk; developed eyes)

Gnathostomata

Jawed vertebrates; jaws evolved from gill arches for more efficient prey capture

Chondrichthyes

Cartilaginous fishes (sharks, skates, rays); fusiform body; heterocercal tail; placoid scales; denser than water with no swim bladder; internal fertilization via claspers

Ampullary organs of Lorenzini

Shark sensory organs that detect weak electrical fields produced by prey movement

Lateral line system

Row of neuromasts in sharks (and fishes) that detect vibrations in the water

Shark reproduction

Oviparous = lays eggs; ovoviparous = live young develop in ovarian cavity; viviparous = live young develop with placenta

Osteichthyans

Vertebrates with bony skeleton; have scales, operculum, and swim bladder; external fertilization

Operculum

Bony plate covering and protecting the gills in Osteichthyans

Swim bladder

Gas-filled organ in most bony fishes for buoyancy control; absent in tuna and flounder; regulated by rete mirabile and reabsorption area

Ganoid scales

Primitive, non-overlapping scales found in ancient bony fishes

Placoid scales

Tooth-like scales found in cartilaginous fishes

Cycloid / Ctenoid scales

Overlapping scales found in modern teleosts

Marine teleost osmoregulation

Hypo-osmotic to seawater; must drink seawater and excrete salts to avoid losing water by osmosis

Freshwater teleost osmoregulation

Hyper-osmotic to surrounding water; must pump water across kidney and absorb salts from gills

Actinopterygii

Ray-finned fishes; fins supported by thin bony flexible rays; sickle-shaped tail correlates with faster swimming

Sarcopterygii

Lobe-finned fishes; fins supported by skeletal extensions of pectoral and pelvic areas, moved by muscles; includes tetrapods

Tetrapoda

Vertebrates evolved from lobe-finned fishes; 4 limbs with bony endoskeleton

Amphibia

Quasiterrestrial, ectothermic tetrapods; gills as larvae, lungs as adults; buccal pumping to breathe; includes salamanders, newts, frogs, toads

Poison dart frogs

Amphibians with aposematic coloration warning of alkaloids and batrachotoxins

Reptilia

Amniotes with desiccation-resistant egg; keratin scales impermeable to water; excrete uric acid; thoracic breathing (negative pressure); advanced circulation and senses

Amniote egg

Desiccation-resistant closed shell permeable to O2 and CO2; allowed vertebrates to reproduce on land

Testudines

Turtles; high nest temperature produces females

Squamata

Lizards and snakes; Jacobson's organ detects chemicals; have venom glands

Crocodilia

Crocodiles and alligators; 4-chambered heart; secondary palate allows breathing while holding prey; teeth in sockets; care for young; high nest temperature produces males

Aves

Birds; feathers and air sacs; light skeleton; no bladder; double circulation; ratite = flightless, carinate = flighted; feathers are modified keratin reptile scales

Precocial young

Bird hatchlings covered with down and immediately active

Altricial young

Bird hatchlings with no down that require extended parental care

Mammalia

Milk-producing amniotes; endothermic; high metabolism; secondary palate; 4-chambered heart; highly developed brain

Eccrine glands

Sweat glands producing watery secretion; found in hairless places; function in temperature regulation

Apocrine glands

Sweat glands producing milky secretion; found in hair follicles

Sebaceous glands

Produce sebum to protect hair and skin

Mammary glands

Produce milk for offspring; defining feature of mammals

True horns

Grow continuously; hollow keratinized epidermis over a bone core (e.g. cattle, goats)

Antlers

Solid bone covered by vascularized velvet; shed annually; found only in males

Rhino horn

Made of keratinized filaments from the dermis matted together; not true bone

Prototheria

Egg-laying mammals (e.g. platypus); no pregnancy

Metatheria

Marsupials; pouched; short gestation period; young born undeveloped

Eutheria

Placental mammals; longer gestation; extended parental care; placenta provides embryo nutrients