lec 6: Rwptiles, birds, non-hominin mammals Flashcards
Amniotes
tetrapod vertebrates (reptiles birds mammals) defined by amniotic egg ( extra embryonic membranes protect embryo allowing for reproduction on land without needing water) crucial for terrestrial success, adaptation to desiccation (drying out) Has keratinized skin (reduces water loss) expandable rib cage (oxygen intake)
300 mya
most primitive amniotes (reptiles) appear, development of amniotic egg, amniotes split into synapsids (later mammals) and diapsids (leading to reptiles and birds)
diapsid ancestor
early reptile-like amniote w/ two temporal holes in skull (lighter skull, stronger bite force) and orbit (eye sockets) allowed reptiles to have greater diversity (dinosaurs reptiles birds)
Class reptilia
Amniotic egg, cold blooded, scales/keratinized skin (reduce water loss) 3 chambered heart
order squamata
Snakes/lizards
order crocodilla
Alligators, crocs, caimans
order testudines
turtles, tortoises
Class Aves
Birds! Have feathers, warm blooded (endothermy), hollow bones (flight) beak, 4 chambered heart (supports higher metabolism for flight) amniotic egg, air sac respiratory sys (one way airflow sys allows for more oxygen = longer flights)
150 mya
Archeoptrix lived, direct evidence of birds being related to dinosaurs, both reptile/bird traits (teeth, diapsid skull, feathers) evidence that feathers evolved before flight
order strigiformes
owls
order passeriformes
perching birds
order falconiformes
hawks, falcons
Mammals (also amniotes)
evolved from synapsid ancestor (only one temporal hole in skull providing space for larger jaw muscles) Jaw bones (articular/quadrate) evolved into middle ear bones (superior hearing to ancestors) *produce milk/have hair, warm blooded, 4 chambered heart, heterodontic dentition (diff types of teeth, molars, incisors, canines)
order monutremata
egg laying mammals (platypus, echidnas (spiky anteater)
order marsupialia
underdeveloped young, complete development in mothers pouch (marsupium) (kangaroos, koalas, opossums)
order lagomorpha
characterized by large incisors (herbivores) rabbits, hares
order rodentia
ever growing incisors (squirrels, beavers, mice, rats, porcupines)
order carnivora
Meat eating, dogs, wolves, cats, bears
order cetartiodactyla
even-toed (cows, deer, pig, sheep) - artiodactyla.
order cetaceans
Fully adapted to aquatic life (whales dolphins porpoises)
order perissodactyla
odd-toed (horses, zebras, tapirs, rhinos)
order chiroptera
Bats, only mammals capable of true flight
order primates
characteristics: hands/feet (grasping) forward facing eyes, large brain, social behavior/learning
55 mya ~ first true primates appear (lemurs, tarsiers)
35 mya ~ new world monkeys (S. America)
25 mya ~ old world monkeys (Africa)
15 mya ~ apes
