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50 Cards in this Set
- Front
- Back
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vertebrates |
-have a backbone -365 MYA vertebrates evolve limbs and colonize land terrestrial vertebrae: amphibians, reptiles, and mammals -vary enormously in characteristics such as body mass |
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Chordates |
-phylum that includes vertebrates -bilaterian animals -clade: Deuterostomia |
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Which two groups of invertebrates still belong to the deuterosome clade? |
cephalochordates & urochordates |
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Derived characteristics of chordates |
-notochord -dorsal, hollow nerve cord -pharyngeal slits or clefts -muscular, post-anal tail |
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Notochord |
-a longitudinal, flexible rod located between the digestive tube and the nerve cord -provides skeletal support -provides a firm but flexible structure against which muscles can work during swimming -in most vertebrates, adults only retain remnants of the notochord |
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Dorsal, Hollow Nerve Cord |
-unique to chordates -a plate of ectoderm that has rolled into a tube located dorsal to the notochord -develops into CNS: brain and spinal cord |
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Pharyngeal Slits or Clefts |
-pharyngeal clefts develop into slits that open into the pharynx -pharyngeal slits allow water entering the mouth to exit the body without passing through the entire digestive tract -function as suspension-feeding devices -have been modified in vertebrates to be gills -in tetrapods the arches develop into parts of the ear and other structures of the head and neck |
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Muscular, Post-Anal Tail |
-tail that extends posterior to the anus -in many species it has been greatly reduced -contains skeletal elements an muscles, helps propel many aquatic species in the water |
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Lancelets |
-earliest diverging group of living chordates -blade-like shape -cilia draw seawater into the lancelet's mouth -swimming mechanism of fishes -globally rare, found in large densities in Tampa Bay, FL |
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Tunicates |
(urochordata) -larva use tail and notochord to swim through water in search of a suitable substrate -once settles undergoes radical metamorphosis -as an adult, tunicate draws in water through an incurrent siphon -shoot a jet of water through their excurrent siphon when attacked, have nickname "sea squirts" -have lost 4 HOX genes |
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Hagfish |
-jawless vertebrates with highly reduced vertebrae and a skull made of cartilage -all marine species -most are bottom dwelling scavengers -produces slime to defend against predators |
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Lamphreys |
-jawless vertebrate -marine and freshwater species -mostly parasitic -skeleton made of cartilage made of proteins (not collagen) |
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When do chorodate fossils show up? |
530 MYA during Cambrian Explosion -most primitive is a Haikouella (resembles a lancelet) -early signs of skull can be seen in Myllokunmingia |
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When do vertebrate fossils show up? |
500 MYA |
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conodonts |
a group of slender, soft-bodied vertebrates that lacked jaws and whose internal skeleton was made of cartilage -large eyes to locate prey -became extinct by end of Devonian period |
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Gnathostomes |
jawed vertebrate -appear 440 MYA -diverse groups including sharks, ray-finned fishes, lobe-finned fishes, amphibians, reptiles, and mammals -have duplicated genome -enlarged forebrain -enhanced sense of smell and vision -lateral line system |
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lateral line system |
organs that form a row along each side of the body and are sensitive to vibrations in the surrounding water |
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placoderms & acanthodians |
"plate skinned" -earliest gnathostomes -444-359 MYA |
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Chondrichthyans |
sharks, rays, and their relatives -have a skeleton of cartilage -most sharks have a streamlined body and are swift swimmers -trunk and tail fin propel them forward -dorsal fins as stabilizers -sharks are more than than water and will sink if they stop swimming -sharks have sharp vision but cannot distinguish colors -regions in the skin on their head that can detect electric fields generated by other animals |
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oviparous |
eggs hatch outside the mothers body, these sharks release their fertilized eggs after encasing them in protective coats |
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ovoviviparous |
eggs are retained in the oviduct -nourished by the egg yolk, the embryos develop into young that are born after hatching within the uterus |
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viviparous |
young develop within the uterus and obtain nourishment prior to birth |
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cloaca |
a common chamber in the shark that has a single opening to the outside -reproductive tract, excretory system, and digestive tract all use this hole |
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Rays |
-mostly bottom dwellers that feed by using their jaws -have a flattened shape and use their pectoral fins to move through water |
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Osteichthyans |
-UNLIKE chondrichthyans: all have an ossified (bony) exoskeleton with a hard matrix of calcium phosphate -tetrapods included in this group -mostly fishes breathe with gills -oviparous (mostly) |
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operculum (fishes) |
a protective bony flap that covers the chambers with gills |
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swim bladder (fishes) |
how fishes retain their buoyancy by filling their swim bladders with air -lungs arose in early osteichthhans; later swim bladder evolved from lungs: Charles Darwin was WRONG |
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Ray-Finned Fishes |
named for the body rays that support their fins -originated 444-416 MYA -cod |
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Lobe-fins |
-originated during the Silurian period (444-416 MYA) -key derived trait: presence of rod-shaped bones surrounded by a thick layer of muscle in their pectoral and pelvic fins -today only three lineages survive 1) coelacanths 2) lungfishes 3) tetrapods |
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Which clade did tetrapods develop from and when? |
gnathostomes: lobe-fins 365 MYA |
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Derived characters of tetrapods |
-four feet -limbs and digits -head is separated from the body by a neck with one vertebrae so the scull can move vertically and a second so the scull can move horizontally -bones of the pelvic girdle are fused to the backbone -no gills -pharyngeal cleats give rise to parts of the ear |
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Amphibians |
6,150 species in three clades -salamander "tailed ones" -frogs "tail-less ones" -caecilians "legless ones" -mostly found in damp habitats -rely on moist skin for gas exchange -external fertilization -lay eggs in water |
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Salamanders |
-aquatic or terrestrial -Paedomorphosis is common among aquatic salamanders |
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Frogs |
-powerful hind legs -"toads" are simply frogs that have leathery skin or other adaptations for life on land -many adaptations to avoid being eaten |
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Caecilians |
-legless, nearly blind, superficially they resemble earthworms -inhabit tropical areas |
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Larval Stage of a Frog |
"tadpoles" -aquatic herbivore with gills, a lateral line system, and a long, finned tail -"second life" the tadpole develops legs, lungs, a pair of external eardrums, and a digestive system adapted to a carnivorous diet |
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Amniotes |
a group of tetrapods whose extant members are the reptiles and mammals -The amniotic egg is the major derived trait -use their rib cage to ventilate their lungs -350 MYA |
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Amniotic egg |
amnion-encloses a compartment of fluid that bathes the embryo and acts as a hydraulic shock absorber yolk sac-the yolk sac contains the yolk, a stockpile of nutrients. Chorion-gas exchange between the embryo and air Allantois-a disposal sac for certain metabolic wastes produced by the embryo |
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Reptiles |
clade includes: tuataras, lizards, snakes, turtles, crocodilians, and birds along with a number of extinct groups such as plesiosaurs and ichthyosaurs -reptiles have scales (different from amphibians) -lay eggs on land -fertilization occurs internally before the eggshell is secreted -"cold blooded"-don't use their metabolism to control their body temperature |
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ectothermic reptiles |
they absorb external heat as their main source of body heat |
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endothermic birds |
capable of maintaining body temp through metabolic activity |
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parareptiles |
-one of the first major groups to emerge -large, stocky, quadrupedal herbivores -died 200 MYA at end of triassic period |
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diapsids |
-pair of holes on each side of skull -composed of two main lineages lepidosaurs-tuataras, lizards, snakes archosaurs-crocodilians, pterosaurs, dinosaurs |
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Pterosaurs |
-originated in late Triassic period -first tetrapods to exhibit flapping flight -consisted of collagen-strengthened membrane that stretched between the trunk or hind leg and a very long digit on the foreleg |
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dinosaurs |
very diverse group -ornithischians-herbivores, tail clubs and horned crests -theropods-bipedal carnivores. T-Rex as well as ancestors of birds -all dinosaurs became extinct (besides birds) by the end of the Cretaceous period (65.5 MYA) -asteroid or commet extinction? |
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Turtles |
-all have a boxlike shell made of upper and lower shields that are fused to the vertebrae, clavicles, and ribs -oldest known fossil dates 220 MYA -live in deserts, ponds, rivers, sea |
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Lepidosaurs |
-tuataras -lizards and snakes or squamates -snakes descended from lizards with legs -snakes are carnivorous, sensitive to ground vibrations, olfactory organs on roof of the mouth |
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Crocodilians |
-Alligators and crocodiles belong to a lineage that reaches back to the late Triassic -confined to warm regions of the globe |
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Birds |
-archosaurs -weight-saving modifications that make flying more efficient: lack urinary bladder, only one ovary, gonads are small, toothless -wings and feathers: made of beta-keratin -birds are endothermic -acute vision and fine muscle control -excellent eyesight -fertilization is internal, engage in elaborate courtship rituals feathers evolved before flight |
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ratites |
-ostrich, rhea, kiwi, cassowary, emu, are all flightless -penguins make up the flightless order Sphenisciformes, have powerful pectoral muscles -flamingoes are filter feeders |
