Vertebrates Lecture Flashcards

Class Chondrichthyes (Sharks)

• To immobilize a shark, one can punch it in the nose or use a magnet (sharks don't like magnets).

Class Osteichthyes (Bony Fishes)

• Subphylum Vertebrata: Animals with a vertebrae.

• Two groups:

  • Ray-finned fish (99.9% of fish).

  • Lobe-finned fish (coelacanth and lungfish).

• Coelacanths were thought to be extinct but were rediscovered about 50 years ago.

Ray-finned Fish

• Fins have bones that radiate outwards, covered by thin skin.

• Fins are used for balancing and steering underwater.

• Most have a swim bladder or gas bladder containing nitrogen gas for buoyancy.

• Have an operculum (covering over the gills) to draw water into the gills, allowing them to breathe without constant swimming.

Lobe-finned Fish

• Bones in fins resemble bones of land animals.

• Fins are more for walking or crawling.

• Includes coelacanths and lungfish.

Swim Bladder Disease

• Disease found in aquarium fish. May be due to infection or overeating.

• Interferes with swim bladder function, causing the fish to flip over.

• Feeding green peas is suggested as a remedy.

Swim Bladders as Valuable Commodity

• The swim bladder of certain fish in the Gulf of Mexico/California is highly prized in Asia (up to $10,000).

• Illegal fishing due to declining populations.

  • Example case: Man drying 214 swim bladders worth $3.6 million.

• Negative consequences: Nets catch unwanted animals like porpoises.

Lobe Fin Fish Details

• Scientists believe they are the direct ancestors of animals that moved onto land.

• Ancestors of tetrapods (four-limbed animals).

• First land animals likely resembled amphibians.

Fish Respiration

Gills and Capillaries

• Fish breathe through gills; gas exchange occurs in capillaries.

• Countercurrent flow of blood and water maximizes oxygen diffusion into the capillaries.

• In countercurrent flow, blood and water flow in opposite directions, ensuring efficient gas exchange.

Shark Respiration

• Sharks swim to pass water through their gills.

Tetrapods

• Animals that move on land evolve feet with digits, ears for airborne sounds, and lungs.

• Early land animals (amphibians) have both lungs and gills.

Class Amphibia

• Includes frogs, toads, salamanders, and caecilians.

• The word "amphibian" means "two lives" (aquatic tadpole stage and terrestrial adult stage).

• Ectothermic (cold-blooded).

• Amphibians have both lungs and gills.

  • Tadpoles have gills. Adults have lungs.

  • Many amphibians breathe through their skin.

Sensitivity to Pollution

• Amphibians are susceptible to water pollution due to skin breathing and can serve as pollution detectors.

• Insecticides and agricultural chemicals may mimic hormones, causing abnormal limb development.

Amniotic vs Non-Amniotic Eggs

• Amphibians do not lay amniotic eggs (shelled eggs with an amnion).

• Amphibian eggs have a jelly-like protective layer (not an amnion) that may prevent drying out and protect from predation.

Orders of Amphibians

• Urodela (Caudata): Newts and salamanders.

• Anura: Frogs and toads.

• Apoda: Caecilians.

Order Urodela (Caudata)

• Contains newts and salamanders, mostly found in North America.

• Adults and young have tails.

• Newts arms tend to be angled, salamanders' arms tend to be at a right angle.

Toxic Newts

• Taricha granulosa exudes a poison (tetrodotoxin), like puffer fish.

Order Anura

• Frogs and toads that do not have tails in their adult forms.

• Frogs tend to have colorful, smooth skin and legs for jumping.

• Toads tend to have brownish, bumpy skin and hop rather than jump.

• Frogs have teeth-like ridges in their upper jaw.

• Frogs are found near water, while toads can be found away from water.

• Frog eggs are laid in clusters; toad eggs are laid in long chains.

Poison Dart Frogs

• Used by native people in the Amazon for hunting by dipping arrows in their skin.

• Toxins are derived from their diet (possibly beetles).

• Native people use trace amounts of poison for spiritual rituals, though it can be fatal.

Surinam Toad

• Eggs merge into the female's skin and develop into tadpoles until they emerge.

Transparent Frog

• Species with transparent underside, showing its organs.

Order Apoda

• Contains caecilians, which look like a cross between snakes and earthworms.

• They do not have limbs and have tentacles for smelling or sensory purposes.

• They have small, non-functional eyes and live underground.

• They use internal fertilization (males inject sperm into females).

• Some species of mother thicken their skin for scraping off the skin by young for food.

Amniotes

• Reptiles, birds, and mammals are amniotes.

• Amniotic eggs have an amnion layer with amniotic fluid surrounding the embryo.

• Amniotes also have an allantois and chorion.

Amnion Structures

• Amnion: Contains amniotic fluid to cushion the embryo.

• Allantois: Used in respiration and waste excretion.

• Chorion: Gives rise to the placenta for nutrient and waste exchange.

• Most amniotes lay shelled eggs and have thick skin to prevent water loss.

• They have rib cages for respiration and well-developed kidneys and large intestines for water retention.

Class Reptilia

• Includes tuatara, lizards, snakes, turtles, crocodiles, and dinosaurs. Have waterproof skin and lay shelled eggs.

• Ectothermic.

• Very efficient at converting food into energy.

• Have a closed circulatory system.

• Amphibians and Reptiles have a three-chambered heart.

  • Two atria and one ventricle.

Crocodile Evolved Hearts Structure

• Crocodiles are considered the most evolved reptiles. Although technically they have a three-chambered heart, their hearts begin to show two ventricles.

Reptile's Kidney and Urine

• Reptiles cannot produce concentrated waste because their kidneys lack a Loop of Henle to reabsorb water.

Orders of Reptilians

• Crocodilia: Crocodiles, alligators, and caimans.

• Sphenodontia: Tuatara.

• Squamata: Lizards, snakes, and skinks.

• Testudines: Turtles, tortoises, and terrapins.

Order Crocodilia

• Crocodilians are considered the most advanced reptiles based upon their heart.

• Scales are covered with scutes that are shed individually.

• They are found in warm/tropical climates because their stoop does not protect them against cold weather.

• Crocodilians do not have sweat glands and open their mouths to release heat (panting just like dogs do to release heat).

• They can run faster than humans, are good at climbing trees, and have a strong sense of smell, sight, and hearing.

Crocodilia Eyelids Structures

• Consist of Three eyelids, with the innermost called the nictitating membrane.

  • The clear nictitating membrane acts as underwater goggles.

  • Tapetum reflects light to improve night vision but is only used with tapetum.

Gender Determination

• Sex is determined by the temperature during egg development (not chromosomes).

• Crocodilians replace their teeth throughout their lifetime and produce tears (crocodile tears).

Crocodilian Muscle Details

• They have strong muscles for closing their mouths but weak muscles for opening them.

Crocodile Compared to Alligator

• How to tell the difference between crocodile and alligator:

  • Alligators and caimans have a U-shaped snout, while crocodiles have a V-shaped snout.

  • Crocodiles have spots on their scales, while alligators do not ("crocs with spots, gators not").

  • When a crocodile closes its mouth, teeth from both jaws are visible. With alligators, only upper teeth are visible.

  • Crocodiles can live in saltwater due to salt glands; you will never find gators in salt water.

Crocodilian Digestion

• Crocodile stomachs have very strong acid that has a pH of 1 to digest hard prey components.

• Crocodiles do not chew and have strong acid for digestion of bones and other hard-to-break-down proteins.

• They never stop growing, and they can get as large as 20' 3".

Order Sphenodonta

• Contains only the tuatara in New Zealand.

• "Tuatara" means "two peaks" in the Maui language.

• Tuatara are ancient reptiles and are considered living fossils and are not closely related to lizards.

• They are the least specialized of the reptiles

Tuatara vs. Lizard Distinctions

• How to tell if this reptile is a Turatara, not a lizard.

  • Tuatara has a third eye in the top of their head; lizards do not.

  • Tuatara does not have visible ears.

  • Tuatara has front teeth; lizards do not.

  • Tuatara are nocturnal only; lizards can be active during the day and mostly inactive at night.

  • Tuatara teeth are projections of the jaw, act like teeth; lizards have real teeth.

  • Tuatara have very slow metabolism.

Turatara Life Span Details

• Because of their slow metabolism, turataras live a long time (60-70 years or more).

• Their numbers are declining because cats kill them and their reproduction rate is slow, so they are protected in New Zealand.

Order Squamata

• Contains lizards and snakes. Snakes evolved from lizard-like ancestors.

Squamata Bone Structure

• Squamata scales are horny.

• They have bones called quadrate bones that connect lower and upper jaw.

  • These bones allow snakes to dislocate their jaws to swallow large prey.

Other Bone Characteristics

• Primitive snakes like pythons have anal spurs, remnants of legs.

• Skinks are a cross between snakes and lizards that look like snakes but have tiny arms and legs.

Reptilian Eyelid Details

• Burrowing snakes have clear eyelids called a brill for protection.

How Snakes Take in Sensory Information Information

• Snakes possess Jacobson's organs and pit organs for sensory input.

• Jacobson's organ: Used along with their tongue, which picks up chemicals in the air; snake hunts food source to eat.

• Pit organ: Used for detecting heat to sense prey heat from food source.

Coral Snakes

• How to tell a coral snake versus a fake coral snake:

  • Red to black is a friend of Jack; red to yellow will kill a fellow.

Additional Venomous Snake Information

• The most venomous snake is the inland taipan in Australia.

• Different snakes have different venoms that affect the nervous system, blood clotting, and tissue breakdown.

More Snake FYIs

• Flying snake fly through gliding.

• Spitting cobra spits venom for temporary blinding, which does not really do any harm.

Order Testudines

• Includes turtles, tortoises, and terrapins (chelonians).

• Tortoises live on land.

• Terrapins live in brackish water (salt marsh).

• Turtles live in the ocean.

Chalonians Structures

• Has two shells, shells are connected to their bones:

  • Carapace (top shell).

  • Plastron (abdomen shell).

Teeth/Cloaca and Aging

• Modern chelonians do not have teeth but have jaw ridges.

• Their butt is near the cloaca.

  • There is an opening used for waste and egg laying and extracting oxygen. Chelonians live in the water.

  • Aging and cells of old chelonians are very similar to those of young chelonians.