Bio of Vertebrates - Exam 3 Part 1

Ch 7 (Osteichthyes), Ch 8 & 11 (Mods for Life on Land), Ch 12 (Lissamphibia), and Ch 14 (Ecto v. endo)

Osteichthyes

-Bony fishes
-Skeleton has Endochondral bone (some earlier have dermal and perichondral bone)
-Single gill opening, covered by bony operculum
-Jaws present (with teeth in some)
-Gas bladder or lung present. 

Endochondral

Bone; went from cartilage to ossified bone.

Sarcopterygii

-Fleshy-finned or lobe-finned fishes
-Paired fins with a fleshy stalk with internal skeletal axis.
-Contains Dipnoi, Actinistia, and Tetrapodmorpha

Dipnoi (Dipnomorpha)

Lungfishes; under Sarcopterygii

Actinistia

Coelacanths; under Sarcopterygii

Tetrapodmorpha

Tetrapods, under Sarcopterygii

Actinopterygii

-Ray-finned fishes
-Paired fins with membrane supported by rays that radiate from fin base, no fleshy stalk.
-Acipenseriformes, Polypteriformes, and Neopterygii under this. 

Acipenseriformes

Sturgeons and paddlefishes.
Under Actinopterygii

Polypteriformes

Bichirs, reedfishes. Under Actinopterygii

Neopterygii

Has three families: Lepisosteiformes, Amiiformes, and Teleostei

Lepisosteiformes

Gars, under Neopterygii

Amiiformes

Bowfins, under Neopterygii

Teleostei

Teleosts; under Neopterygii

Dipnoi

-Lungfishes.
-Freshwater
-Possess gills and lungs (1 or 2)
-Use of lung(s) is facultative or obligate
-Gills eliminate much CO2, which is highly soluble in water
-Swim via undulation of body, or walk along bottom using paired appendages
-Use paired fins to walk on bottom and even overland to new bodies of water.
-Estivate in mud burrows when water dries- secrete a mucus sac that encloses all but mouth.
-Oviparous with (presumably) external fertilization.

Facultative

Breathes air when O₂ level of water is too low

Obligate

Drown if unable to breathe

Estivate

mud burrows when water dries as a state of dormancy

Actinistia

-Coelacanths
-Closest extant relatives to tetrapods.
-Marine
-Predators are fish and squids
-Swim, but move paired appendages in tetrapod ‘walking’ sequence.
-Viviparous with large young
-No copulatory organs in males

Copulatory Organs

Organs which help the male transfer sperm to female

Polypteriformes and Acipenseriformes

-Few extant relicts from early radiation
-Retain many primitive actinopterygian characters.
-Heterocercal or modified heterocercal tail. 

Polypteriformes

-Bichirs or reed fish
-Least derived extant Actinopterygians
-Elongate and slow moving
-Heavily armored with thick (primitive) scales
-Well ossified skeleton
-Lungs (paired) and gills
-Modified heterocercal tail

Acipenseriformes

-No or little endochondral bone
-Persistent notochord
-Strongly heterocercal tail
-Sturgeons (Acipenseridae)
-Anadromous or entirely freshwater
-Benthic suction feeders (crustaceans and insect larva)
-Many overfished for caviar
-Paddlefishes (Polyodontidae)
-Freshwater rivers
-Elongate rostrum with electroreceptive ampullae
-Filter feeders (zooplankton or small fishes)

Anadromous

Fish born in freshwater, but migrate to saltwater

Primitive Neopterygii

-Lepisosteiformes (gars) and Amiiformes (bowfin)
-Few relicts from earlier Neopterygian radiation
-Vascularized gas bladder - lung
-All other Neopterygians are Teleosts

Lepisosteiformes

-Gars (Lepisosteidae)
-Elongate body
-Freshwater and brackish/estuarine
-Physostomous (use gas bladder as lung)
-Predators
-Long rostrum and jaws with needle-like teeth
-Body armored with thick (primitive) ganoid scales
-Modified (abbreviate) heterocercal tail

Amiiformes

-Bowfin (Amia)
-One species in N. America
-Freshwater
-Generalist predators
-Thinner scales, more similar to teleosts
-Modified (abbreivate) heterocercal tail.
-Bony gular plate.

Elopomorpha

Tarpon, bonefishes, and eels

Osteoglossomorpha

“Bone tongues” and elephantfishes

Clupeomorpha

Shad, herrings, and anchovies

Ostariophysi

Minnows, suckers, piranhas, catfishes, electric eels, and knifefishes

Euteleostei

All other teleosts

Specializations of Fins/Body (Teleosts)

-Homocercal (symmetrical) caudal fin
-With gas bladder, allows horizontal swimming without using paired fins for control.
-Paired fins specialized for other purposes (walking, flying, visual display, others)
-Thin scales to scaleless; more flexible body

Specializations of Jaws (Teleosts)

-Prey-grabber to suction device, increase volume of orobranchial chamber.
-Protrusible Jaw
-Pharyngeal jaws

Protrusible jaw

rapidly extends grasping surfaces forward and increases volume/suction.

Pharyngeal Jaws

Horny or bony teeth/plates on pharyngeal jaws (modified gill arches) crush or grind food (makes hard prey and plant foods more digestible)

Elopomorpha

-Eels, tarpons, ladyfishes, and bonefishes
-Worldwide
-Mostly marine
-Larvae drift on ocean currents for long periods
-Some are catadromous (live in freshwater, but mature adults migrate to oceans/seas to spawn (& die); young move into freshwater, until maturity. 

Catadromous

Live in freshwater, but mature adults migrate to oceans/seas to spawn (& die); young move into freshwater until maturity. 

Osteoglossomorpha

-Bone-tongues
-Worldwide
-Tropical freshwaters
-Includes the largest strictly freshwater fish
-Elephantfishes use electrolocation

Clupeomorpha

-Shads, herrings, and anchovies
-Worldwide
-Mostly marine, schooling
-Mouth and gills specialized for planktivory, strain plankton from water.
-Some are anadromous

Ostariophysi

-Worldwide, in fresh waters
-Includes over 80% of freshwater fish species
-30% of all extant fish species
-Cypriniformes (minnows and suckers)
-Characiformes (tetras and piranhas)
-Siluriformes (catfishes)
-Gymnotiformes (electric eels and knifefishes)
-Weberian Apparatus in the Otophysi (better hearing, similar to tetrapod hearing)
-Alarm substance (“pheromone”) in skin is a synapomorphy (released when skin is damaged, warning others nearby)

Weberian Apparatus in the Otophysi

-Swim bladder connected to inner ear by small bones (ossicles)
-Sound (pressure) waves vibrate gas bladder (b/c of gases within)
-Bones conduct vibrations to inner ear
-Similar to function of tympanum and ear ossicles in tetrapods
-Gives Ostariophysans better sensitivity and range of sound detection than other fishes. 

Salmoniformes

-Trouts and Salmon
-Freshwater (Trouts)
-Anadromous (salmon)
-Commercially important fisheries

Esociformes

-Pickerals, pikes, muskellunges, and allies
-Freshwater
-Ambush predators

Stomiiformes

-Dragonfishes
-Marine, open ocean and deep sea
-Includes the most abundant vertebrates (bristlemouths)

Myctophiiformes

-Lanternfishes
-Marine, deep sea
-Photophores emit light
-Migrate upward to feed at night, back to deep in the day

Polymixiiformes

-Breadfishes
-Marine, benthic or near bottom

Gadiformes

-Cods, haddock, and hakes
-Freshwater and marine
-Many important wild-caught fisheries, including Atlantic Cod

Zeiformes

-Dories
-Marine, some deep sea

Lampriformes

-Opah and ribbonfishes
-Marine and pelagic, some deep sea
-Oarfish reach up to 8m. 

Acanthopterygii

-Spiny-rayed fishes
-All teleosts have overlapping (imbricate) scales
-Cycloid scales are round, Ctenoid have bony projections on posterior
-Bony spines (and soft fin rays) in dorsal, anal, and pelvic fins
-Pectoral fins lateral instead of ventral
-Pelvic fins thoracic of instead of abdominal
-Pneumatic dust closed (absent) = physiclistous

**STRUCTURE

GENERALIZED BASAL EUTELEOST V. GENERALIZED ACANTHOPTERYGIAN

Trachichthyiformes

-Flashlightfishes
-Marine
-”Flashlight” photophore beneath eye, turns on and off

Holocentriformes

-Squirrelfishes
-Nocturnal reef (marine) fishes
-Make sounds like a squirrel

Batrachoidiformes

-Toadfishes and midshipmen
-Marine
-Produce sound by vibrating gas bladder
-Large choruses can be heard above water

Gobiiformes

-Gobies and mudskippers
-Tropical and temperate nearshore marine (few freshwater)
-Many able to move on land (even climb waterfalls)
-Defend “terrestrial” territories

Percomorpha

-All the rest of the Acanthopterygii spiny-rayed fishes
-Marine and freshwater
-Mackerels, tuna, and seahores are basal
-Perciformes includes many of our freshwaer fishes, other than the Ostariophysi (sunfishes and darters)

Anguilliform

-Most of body undulates in sinusoidal “waves”
-Elongate, flexible bodied fishes; eels, lampreys, and sharks

Subcarangiform

Undulation limited to posterior half of body

Carangiform

-Undulations limited to the caudal region, less than half a wavelength.
-Less flexible, stouter-bodied fishes.

Thunniform

Rapid, narrow oscillations of caudal fin, body stays straight to reduce drag. 

Ostraciiform

Undulation limited to caudal fin - body inflexible. Boxfishes.

Labriform

Most propulsion from pectoral fins and little from tail. Wrasses

Amiiform

Sine waves along length of elongate anal fin. Bowfin

Gymnotiform

Sine waves along length of elongate anal fin. Knifefish

Balistiform

Sine waves along both dorsal and anal fins - triggerfish.

Moliform (molas)

No caudal fin and inflexible body. Dorsal and anal fins oscillate side to side.

Reproductive Modes in Actinopterygii

-Most are oviparous, with external fertilization of eggs.
-Some have internal fertilization.
-Some are viviparous - lecithotrophy to matrotrophy.
-Eggs are demersal (buried, attached, or held in a nest) or pelagic (free-floating)
-Parental care ranges from none, to egg guarding, and brooding of eggs or young in parent’s mouth.

Oviparous

Egg-laying. Young are not born live.

Viviparous

Young born live from mother.

Lecithotrophy

a type of embryonic development where the embryo receives nourishment solely from the yolk present in the egg, with no additional nutrients from the mother after fertilization

Matrotrophy

receiving extra nutrients from the mother after fertilization

Demersal

Eggs are buried, attached, or held in a nest

Pelagic

Eggs are free-floating. Free-floating or swimming, suspended in the water column.

Reproduction in Freshwater Teleosts

-Produce relatively few, large, yolk-rich eggs.
-Eggs are demersal, which prevents eggs from floating away.
-Parents (usually male) guard eggs
-Eggs hatch into young fry, with a reserve of yolk, that soon resemble small adults, in form and habit (no free-living larval stage)

Reproduction in Marine Teleosts

-Produce large numbers of small, buoyant, transparent eggs
-Eggs are pelagic (develop while drifting at sea)
-Eggs hatch into small, free-living, planktonic larvae.
-Larvae feed on microplankton and continue development, for weeks to months.
-Larvae eventually metamorphose (in hours to days) into small adult form, and settle into adult habitat
-Benefits of pelagic spwaning may include: reduce predation of eggs/larve, abundance of plankton in surface waters, greater chance of colonizing other habitat patches.

Sex in Teleosts

Some teleosts exhibit environmental sex determination and hermaphroditism

Hermaphroditism

an individual has both male and female reproductive organs (Functional ovaries and testes)
-Some lose ovaries (become male) as large adults
-One species self-fertilizes, producing homozygous clones.
-Most alternative roles between spawning session or season.

Gonochorism

Sex remains fixed throughout life. 88% of teleosts

Protandry

-Begin as male and later become female
-Largest group member is female and reproductive
-Second largest is male and reproductive
-Upon death of female, largest male becomes female and the largest immature becomes male.
-Large female size = higher fecundity
-Anemone fishes

Protogyny

-Some females and later become male
-Species in which males defend territories against smaller males. 
-Territorial defense allows access to multiple mates
-Large size = better defender of territory
-Some wrasses

Benthic 

On or near the bottom substrate

Epipelagic

-Upper 100 m
-High productivity of plankton, because of high light levels
-High diversity and abundance of fishes
-Below, animals depend on “rain” of detritus from epipelagic for food. 

Mesopelagic

-100 to 1000 m
-Light penetrates to 1000 m or less
-Often migrate vertically, up at dusk and down at dawn.
-Closer to surface = more food, but also greater predation risk.
-Lower diversity and biomass of fishes

Bathypelagic

-Over 1000 m
-Lowest diversity and biomass.
-Food (prey) rarely encountered
-Little activity, low energy lifestyle
-Most have large mouths and stomachs, to consume large meals when food is found
-Many have bioluminescent organs to attract prey (also for communication).
-Use light and olfactory communication to find/recognize mates. 

Coral Reefs

-Among the most diverse ecosystems
-Occur in relatively warm, shallow waters, with low nutrient levels
-Complex, 3 dimensional structures of reefs provides many niches for animal life.
-Reef fishes are almost all Acanthopterygian teleosts.
-Highly adaptable and specialized mouth structure and feeding modes allow food to be collected from complex reef surface.
-Typically have two shifts of fish community. Dinural and nocturnal. 

Dinural

Active in daylight

Noctural

Active in dark of night

Coral reefs are threatened by…

-Harvesting of animals and mining of coral.
-Coastal development and pollution; increased nutrient levels lead to algal growth, covering and killing photosynthetic corals
-Siltation from runoff water, silt covers reef and blocks sunlight
-Unusually high surface water temperatures have killed large areas

Changes required for transition from aquatic to terrestrial life

1.) Ability to respire in air
2.) Ability to move on land
3.) Body able to support its own weight
4.) Sense organs that function in air instead of water
5.) Ability to eat dry food
6.) Skin that resists desiccation and abrasion
7.) Ability to reproduce on dry land
8.) Excretion of nitrogenous waste other than ammonia by diffusion

What helps the ability to respire in air?

Lungs and trachea. Aspiration ventilation in amniotes.

What helps the ability to move on land?

Neck (head and pectoral girdle no longer connected); fins to limbs

What helps the body able to support its own weight

Stronger limbs, limb girdles, and vertebral column…
-Stronger vertebral column
-More complex axial skeleton and musculature

What sense organs that function in air instead of water?

Modification of eyes, ears, olfactory organs, etc.
-Addition of ears with tympanum and ear ossicles

What helps with the ability to eat dry food?

Salivary glands, inertial feeding
-Longer snout, moveable, fleshy tongue

What helps the skin resist desiccation and abrasion?

Keratinization and thickening of epidermis

What helps the ability to reproduce on dry land

Internal fertilization, direct development, amniotic egg

What helps with excretion of nitrogenous waste other than ammonia by diffusion

Kidneys excrete urea (requires water) or uric acid

What gave rise to tetrapods?

Sacropterygian bony fishes

All tetrapods belong to what clade?

Sarcopterygii

The closest relatives to tetrapoda are included in what clade?

Tetrapodomorpha; are extinct now like the Tiktaalik