19.5 - Vertebrate groups Flashcards
Disclaimer - All chordates have 3 tissues: bilateral, complete digestive tract, true coelom
Absence of jaws: Agnatha lacks true jaws, setting them apart from other vertebrate classes.
Membranous roof in the skull: Their skull has a membranous roof, distinguishing them from other vertebrates with bony skulls
Lack of teeth, paired appendages, and exoskeleton: Agnatha do not possess teeth, paired fins, or an exoskeleton.
Agnatha - hagfish and lampreys
Cartilaginous skeleton: Their skeletons are made of cartilage rather than bone.
Placoid scales: Chondrichthyans have rough, tooth-like scales.
Multiple rows of teeth: They continuously replace their teeth throughout life.
Chondrichthyans - cartilage fishes (sharks and rays)
Bony skeleton: Their skeletons are made of bone.
Ray-finned fins: Their fins are supported by bony rays.
Operculum – able to fan water over it gills without swimming
Swim bladder = lung derivate that helps regulate buoyancy (higher lower in water)
Muscles controlling fin – no muscles inside fin
Actinopterygii - ray-finned fish
Lobe-finned fins: Their fins have fleshy lobes with bones similar to tetrapod limbs.
Lungfish: Can breathe air and survive in oxygen-poor environments.
Coelacanths: Ancient fish thought to be extinct until rediscovered.
Bones and muscles inside the fin allow for more types of movement/locomotion on solidish surfaces.
Sarcopterygii - lobe-finned fishes (and technically tetrapods) HUMANS ARE FISH
Four limbs: Tetrapods have four limbs adapted for walking on land.
Lungs for breathing: They can breathe air.
Vertebral column: Backbone provides support.
Tetrapods - Frogs, Salamanders, Caecliiains
Metamorphosis: Undergo a larval aquatic stage (tadpole) before becoming terrestrial adults.
Moist skin: They breathe through their skin. (Gas exchange)
Dual life: They live both in water and on land.
Ectothermic – thermoregulation from external sources
Amphibia - Amphibians
Scaly skin: Have dry, scaly skin.
Ectothermic: They rely on external heat sources for body temperature regulation.
Amniotic eggs: Eggs with protective membranes.
Reptilia - Reptiles
Feathers: Have feathers for insulation, flight, and display.
Hollow bones: Lightweight bones aid in flight.
Endothermic: Birds are warm-blooded.
Adapted to flight, no teeth, very few small post-anal vertebrae, honeycomb bone structure, efficient lungs, efficient circulation.
Aves - Birds
Hair or fur: have hair or fur covering their bodies.
Mammary glands: Females produce milk to nourish their young.
Three middle ear bones: have three tiny bones
(malleus, incus, and stapes) in their middle ear.
Endothermal: are warm-blooded, maintaining a constant body temperature.
Mammals
Large brains: have relatively large brains compared to body size.
Forward-facing eyes: Enhanced visual acuity at the expense of smell.
Flat nails: have flat nails on their digits instead of claws.
Prehensile hands and feet: Adapted for grasping objects.
Order Primates
Bipedal locomotion: walk on two legs.
Reduced canine teeth: Smaller canines compared to other primates.
Increased brain size: exhibit brain expansion.
Tool use and culture: Evidence of early technology and social behavior.
Post anal tail
Hominis
Placenta: have a well-developed placenta, allowing for longer gestation periods and nourishment of the fetus within the womb.
Live birth: They give birth to fully developed live young.
Diverse habitats occupy various ecological niches worldwide.
Mammal - Placental Mammals (Antelope, Groundhog, Dolphin)
External pouch: raise their newborn offspring inside an external pouch.
Less-developed placenta: Their placenta is less efficient, limiting the gestation period.
Live birth: Like placentals, they give birth to live young.
Mammal - Marsupials (Kangaroos, Koala, Wombat)
Egg-laying: lay eggs instead of giving birth to live young.
Milk production: They still produce milk to nourish their offspring.
Spiny anteater (echidna) and platypus are the only living monotremes.
Mammal - Monotremes (Playtpus & Echindna)
