lecture vertebrates 1 - fish to reptiles Flashcards
(18 cards)
Describe (Subphylum) Vertebrata.
Animals with a backbone or vertebral elements (bone or cartilidge), cranium, and usually paired appendages; includes fish, amphibians, reptiles, birds, mammals. (Phylum Chordata)
Describe (superclass) Agnatha.
Jawless fish; filter or detritus feeders; armored head plates; unpaired fins; examples: extinct ostracoderms, living hagfish and lampreys. vertebrate made of cartilage
Describe (class) conodonts.
Extinct jawless vertebrates; known from tiny, tooth-like microfossils; used in biostratigraphy; had feeding apparatus with diverse element shapes. (superclass agnatha)
Describe (Class) Placodermi.
extinct class of armored, jawed fishes that lived during the Silurian to Devonian periods. They were among the first vertebrates to evolve true jaws and paired fins, and are characterized by their bony head and thoracic armor. cartilage skeleton with bony head armor
Describe (Class) Acanthodii.
oldest jawed fish; spines built into front of fins, small scales; Late Ordovician–Early Permian; mix of shark- and bony-fish traits.
Describe (Class) Chondrichthyes.
Cartilaginous fish (made of cartilidge instead of bone); includes sharks, rays, skates; fossils mostly teeth and fin spines; first appeared in the Devonian.
Describe (superclass) Osteichthyes.
Bony fish; internal skeleton of endochondral bone; divided into (class) Actinopterygii (ray-finned) and (class) Sarcopterygii (lobe-finned).
Ray-finned fish have fins supported by thin, flexible rays (bony spines) with no muscle outside the body.
Lobe-finned fish have fleshy, muscular fins with bone and muscle inside the fin, making them more limb-like
Describe (Class) Sarcopterygii.
Lobe-finned fish; fleshy paired fins with bone supports; ancestors of tetrapods; includes coelacanths and lungfish. lobe fins usually are attached like arms at the base
describe (class) actinopterygii
ray-finned fishes, the most diverse and abundant group of vertebrates alive today. Their paired fins are supported by thin, flexible bony rays (not fleshy lobes), and they have a fully bony internal skeleton. ray fins are attached like ram on a motherboard
Describe (genus) Eusthenopteron.
Devonian lobe-finned fish; key transitional form toward amphibians; well-preserved fossils show limb-like fin bones.
Describe (genus) Acanthostega.
Late Devonian amphibian; fish-like tail, limb bones similar to fins; among earliest tetrapods. more aquatic opposed to ichthyostega
describe (genus) ichtyostega
early tetrapods (four limbs) from the Late Devonian, showing a mix of fish and land-animal traits. It had limbs with digits for walking in shallow water or mud, but also retained a tail fin and possible gills, making it a key transitional fossil between lobe-finned fish and land vertebrates. more land based as opposed to acanthostega
Describe (Class) Amphibia.
Early tetrapods; Carboniferous–Recent; often carnivorous; needed water for reproduction; includes temnospondyls.
Describe the amniotic egg.
Key reptile innovation; allowed eggs to be laid on land; contains amnion, yolk sac, and allantois.
Describe (Class) Reptilia.
Amniotes; diversified in the Permian; includes stem reptiles, turtles, lizards, snakes, crocodiles, dinosaurs. can lay eggs on land unlike amphibians
How did jaws evolve in vertebrates?
From modified gill arches that became bony supports for the mouth.
Why are amphibians important in evolution?
They were the first vertebrates to colonize land, though they still relied on water for reproduction.
What key traits allowed reptiles to dominate on land?
Amniotic egg, keratinized skin, stronger limbs, more efficient lungs.
