Bio Ch 29 Flashcards
Chordates
euterostomes; don’t have an exoskeleton; have an internal skeleton made of bone and cartilage to which muscles are attached (allows freedom of movement and attainment of a larger body size than invertebrates)
Notochord
dorsal supporting rod; located just below the nerve cord; majority of vertebrates have an embryonic one of these that is replaced by the vertebral column during embryonic development
Dorsal tubular nerve cord
spinal cord, protected by vertebrae
Gills
respiratory organs of aquatic vertebrates
Cephalochordates
ex. Lancelets; marine chordates
Urochordates
sea squirts; AKA tunicates because adults have a tunic (outer covering) that makes them look like thick-walled, squat sacs
Gnathostomes
animals with jaws
Tetrapods
terrestrial vertebrates with 4 limbs
Amniotes
animals that exhibit an amniotic membrane
Fishes
largest group of vertebrates (28K species)
Ostracoderms
earliest fossils of Cambrian origin were these small, filter-feeding, jawless, finless fish
Agnathans
jawless fishes; have a cartilaginous skeleton and persistent notochord; cylindrical, up to a meter long, have smooth, nonscaly skin
Ectotherms
depend on the environment to regulate their temperature
Fins
projections that are controlled by muscles
Placoderms
extinct jawed fishes of the Devonian period; probably the ancestors of early sharks and bony fishes
Cartilaginous fishes
Chondrichthyes; skeleton composed of cartilage instead of bone; 5-7 gill slits on both sides of the pharynx; lack the gill cover of bony fishes; many have openings to the gill chambers located behind the eyes (spiracles)
Bony fishes
Osteichthyes; majority of living vertebrates (25K species)
Ray-finned bony fishes
majority of fish species; fan-shaped fins supported by a thin, bony ray; most successful and diverse of all the vertebrates
Swim bladder
gas-filled sac many bony fishes have into which they can secrete gases or from which they can absorb gases, altering its pressure
Lobe-finned fishes
possess fleshy fins supported by bones
Lungfishes
fish with lungs and gills for gas exchange
Amphibians
vertebrates that live on both land in in water; typically tetrapods, smooth & nonscaly skin, lungs, double-loop circulatory pathway, sense organs, ectothermy, & aquatic reproduction
Reptiles
very successful group of terrestrial animals consisting of more than 17K species, including birds; have paired limbs, skin, efficient breathing, efficient circulation, efficient excretion, ectothermy, well-adapted reproduction
Amniotic egg
contains extraembryonic membranes, which protect the embryo, remove nitrogenous wastes, and provide the embryo with oxygen, food, and water
Anapsid
skull with no openings behind the orbit (eye socket); ex. turtles
Diapsid
having two openings in the skull behind the orbit (ex. reptiles other than turtles; birds)
Synapsid
having one opening in the skull behind the orbit (ex. mammals)
Dinosaurs
varied greatly in size and behavior; average size = chicken; some were the largest land animals ever to live
Birds
share a common ancestor with crocodilians and have traits such as the presence of scales (feathers = modified scales), a tail with vertebrae, and clawed feet that show they are indeed reptiles
Endotherms
use metabolic heat to maintain a constant internal temperature; property associated with efficient nervous, respiratory, and circulatory systems
Mammals
include the largest animal ever to live (blue whale), the smallest animal (Kitti’s bat), and the fastest land animal (cheetah); distinguished by hair, mammary glands, skeleton, internal organs, and internal development
Monotremes
egg-laying mammals that include only the duck-billed platypus and two species of echidna (spiny anteaters); term refers to the presence of a single urogenital opening (cloaca), which is a shared excretory & reproductive canal
Marsupials
pouched mammals; ex. kangaroos, koalas, Tasmanian devils, wombats, sugar gliders, and opossums; have a true uterus
Placental mammals
AKA eutherians; dominant group of mammals on Earth
Placenta
very specialized organ for the exchange of substances between maternal blood and fetal blood
