Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
|
Characteristics of Early Vertebrates
|
-Early Vertebrates, most likely marine and jawless
-500+ Ma -Tripartite brain -skull and sense organs -gills and respiration -external armor -Aspidin -Ostracoderms in hagfish and lampreys- extensive radiation about 400 mya |
|
|
Characteristics of gnathostomes
|
-jaws
-480 MA early Ordovician -Placoderms- extinct -Acanthodians –extinct -Osteichthyans- bony fish -Chondrichthyans- cartilaginous fish |
|
|
What is some Vertebrate Fossil Evidence
|
-Cambrian ~540 Ma
-Myllokumingia -Haikouichthys- fish shaped body plan with distinct cranium and myomeres, no bone or mineralized scales, paired sensory structures -Late Cambrian ~500Ma -Conodonts- small with lots of elements that are spine and cone like, microstructures similar to dentine -Ordovician ~480 Ma -Ostracoderms- highly diverse -First jawed fishes |
|
|
Characteristics of Ostracoderms
|
-“shell skin” or bony armor
-more derived than extant agnathans -10-15 cm length -Movable mouth plates -Small, soft-bodied prey -Midline dorsal fin |
|
|
Why did ostracoderms have bony armor/ what was it made from?
|
- hydorxyapatite, enamel and dentine found in the bony armor of ostracoderms
-Defense against predators -Protective insulation to electroreceptors -Phosphorus storage Ostracoderms more closely related to gnathostomes, hag fish thought to be most primitive form and shares more characteristics with ancestral vertebrates. -body concentration fluid same as environment in which they lived in primitive ostracoderms |
|
|
What are some characteristics of Myxinoidea
|
-~40 species
-Marine -Deep-sea, cold-water scavengers -smell their food -Mucus glands, protein threads (tons of mucus)- protein thread will explode and can produce a lot of mucus, can deter predators will knot its body to take of mucus and sneezes to empty nasal passages -No vertebrae -Two horny plates in mouth, with long prehensile tongue Slime eel products (another name for hagfish) -eat hagfish (Korean ) also can become leather -External gill openings, species vary can be 1-15, large blood sinuses and low blood pressure, have accessory hearts in liver and hearts which are not controlled by CNS- similar to amphixious and lampreys -similar to vertebrates in several ways, many females few males. Eggs hatch into small hagfish no larval stage. |
|
|
Characteristics of Petromyzontoidea
|
-~40 species
-Vertebrate structures -Parasitic on other fish- tight attachment to host -Oral hood, spines -Anticoagulant -Nasohypophysial opening-duct allows for respiration ability -Eye and pineal body- well developed, photoreceptive hole on top of head -Heart innervated -tidal ventilation -Velum keeps water from flowing out respiratory tube and into the mouth |
|
|
Characteristics of Lamprey Lifestyle
|
-Anadromous- spend most of adult of life in salt water ocean and span in fresh water and die when they spawn
-Ammocoetes (used to be genus name now is the larval name for the lamprey) -3-7 years filter feeding -Adult 1-2 years -exotic introductions and expansions -problem in northeast |
|
|
Characteristics of Gnathostome Evolution
|
-Origins in Agnathan radiation
-Jaws and Teeth -Paired fins -Hydorfoils- gives fish thrust for propulsion -Defense (spines)- control movement -Heteroceral caudal fin -colored fins and altered fins (spines) -caudal fin used for quick propulsion -Hox gene complex duplicated a second time |
|
|
Characteristics of Teeth
|
-Bony fish, tetrapod teeth embedded
-Chondrichthyian teeth form in skin -Amphibians with pleurodont teeth- teeth set in lingual part of jaw -Many reptiles with acrodont teeth – teeth fused to jaw bone not always upright -Archosaurian reptiles and mallas with thecodont teeth- set in tooth socket and held in place by periodontal ligaments |
|
|
What are some gnathostome specializations?
|
-Jawed and hypobranchial muscles- innervated by spinal nerves- allow added suction for feeding
-Two distinct olfactory tracts leading to nostrils- different from jawless vertebrates -Elongated cranium both anteriorily and posterior for more complex systems -Complex Vertebrate- notochord by spinal column -Ribs- allow for anchorite of muscle s- horizontal septum/lateral line separation -Three semicircular canals- likely improve navigation, orientation in three dimensions -Myelin sheath- new to nervous system, increase signals -Conus arteriosus in heart, added chamber in ventricle smooth out pulsitive nature of blood through heart |
|
|
Characteristics when vertebrates began moving towards jaws
|
-Vertebrate jaws from cartilage of neural crest- first two arches
-From mandibular arch -In a very forward position -Ancestral condition non modified brachial system- derived to agnathans and gnathostomes -Spiracles- water intake in cartilaginous fishes |
|
|
How did gills become jaws?
|
-Jawless and Jawed considered two separate evolutionary lineages
-Nonhomology in branchial arches -Pouched vs. lensshaped gill openings |
|
|
Characteristics of Mallatt reconciliation
|
-Gill anatomy similar between lamprey and sharks
-Pouched gills primitive -Internal brachial arches lost in jawless fishes, external lost in jawed fishes -Mandibular for ventilation -higher metabolic respiration, brachial arches become more muscular water through pharynx, gnathosomes can such food and water in their mouths easier |
|
|
What are the jawed fishes that radiate?
|
Four distinct clades
-Placoderms -Acanthodians -Chondrichthyans -Osteichthyans -Actinoptergians- most alive today -Sarcopterygians- lobed fined fishes gave rise to tetrapod, extensive extinction events Placoderms most perimive |
|
|
Characteristics of the Placoderms
|
-Armored ‘plate skin’- ornamental in structure, jointed between head and trunk region
-Shield in head and trunk portions -Mineralized perichondral bone in endoskeleton- unique to the bony fish -pelvic fins, originated in different ways than other -highest diversity in their time -Benthic marine (deep sea dwelling marine organisms -Lamprey-like structures have simple myomeres, have 7 muscles that move eye unlike others have 6, nerves lack sheaths, lack teeth instead have teeth plates, semidentine, pelvic appendages -Pelvic appendages in some but is thought to be sexually dimorphic |
|
|
Characteristics of the Acanthodians
|
-Stout spines
-Up to 6 pairs of ventrolateral fins -Early Devonian diversity -marine and freshwater became freshwater in Devonian -Midwater dwellers -Sister to Osteichthyes -Resemble Chondrichthyans also -have tooth whorls, produced from skin instead of dermal bone, resembled cartilaginous fish |
