Vertebrates 2 - Classification Flashcards
3 domains
Prokarya, Archaea, Eukarya
Kingdoms in Eukarya
Protists, Plantae, Fungi, Animalia
Phylum of vertebrates
Chordata (falls under Animalia Kingdom)
Breakdown of Chordata
Urochordata (tunicates), Cephalochordata (Amphioxus), Craniata (Hagfish, vertebrates)
5 synapomorphies of all chordates (p28)
Pharyngeal pouches, Notochord, Endostyle, Hollow Nerve chord, postanal muscular tail
Pharyngeal pouches
Becomes parts of gills, or inner ear.
Endostyle
groove in pharynx. In some vertebrates it becomes part of thyroid; other just stays as a groove.
Notochord
Fibrous tissue like cartilage that acts as a support for the body. Found on Dorsal side below the nerve chord. Sometimes found in adult.
Hollow Nerve chord
Anterior end may become brain in higher vertebrates
Postanal tail
Muscular, past anal opening. Present at some point in development.
Urochordata
Sea squirts. Don’t move. Filter feed. Adult doesn’t look like vertebrate, but larva stage is mobile and has all the vertebrate characteristics.
Cephalochordata
Lives buried in sand, filter feeding. Possesses chordata characteristics.
Are Urochordata or Cephalochordata more closely related to Craniata?
Actually Urochordata (genomic comparison).
Craniata
Has a cranium (brain case); Cephalization (specialized sensory structures at anterior end)
Craniata categories
Hagfish and vertebrates.
Craniates synapomorphies
Neural crest cells; brain case; complex sense organs; tripartite brain; complex endocrine system; muscularization of the gut tube; differentiation of digestive system; multichambered heart; type of hemoglobin
Neural Crest cells
Become part of peripheral nervous system. Develop during development
Tripartite brain
A true brain. Forebrain, midbrain, hindbrain.
How are vertebrates classified?
Generally by shared anatomical characteristics; in last 20 years we use molecular comparisons.
Examples of shared anatomical characteristics (p15)
Amniotic egg, hair, endothermy, viviparity, marsupium.
Closest living relative of whales and dolphins?
The hippo and other even-toed ungulates like deer (archyodactyls). Determined by molecular phylogeny.
Gnathostome
Organism with a Jaw. Includes all vertebrates except agnathians (lampreys and hagfish)
Importance of Extinct Animals
fig 3-2
Agnatha
Jawless fish, about 120 species. Hagfish and lampreys (closely related).
Hagfish
mixiniformes. Benthic, scavengers. Do not have vertebrae. Only a notochord to support the body which is not as specialized as a real vertebral column. Secrete lots of mucus as defense.
Lamprey
petromyzontiformes. Open ocean and benthic. Sometimes parasitic.
Chondrichthyes
Cartilaginous fish. No bone, just calcified cartilage. Sharks and Rays (and Ratfish and chimeras). Large, diverse group, 1000 species.
Osteichthyes
Bony fish. Bone replaces cartilage. 29000 species. 3 main groups: Ray-finned fishes (majority). Coelacanths and Lungfishes (only 8 species), have fleshy fins with more bones (more similar to an arm).
Names for Ray-finned fish, Coelacanths and lungfishes
Actinopterygii, actinistia, dipnoi
Amphibia
6500 species. Anurans (frogs - no tail); Salamander (Urodela), Caecillians (legless amphibians). Live part of life in water and part in land.
Reptilia
8200 species. Testudinae (turtles, torteses), Lepidosaura (snakes and lizards), Crocodilia. Thicker skin, more developed lungs.
Aves
10000 species. Ratites (flightless), and Neognatha (all others, including penguins). Feathers, high metabolism, 4 chambered heart, light skeleton, wings.
Mammalia
5500 species. Monotreams (echidna, platypus - no teats, rather pores), metatheria (marsupials - pouch - birth to underdeveloped young), eutheria. Mammary glands, hair.
Vertebrate evolution timeline
Pikaia 570mya, Jawless fish 450mya, Jawed 415mya, First tetrapods 350 mya, First amniotes 300mya, First dinos 250mya, mammals 200mya, birds 140mya,
Anatomical terminology
Anterior/rostral, caudal/posterior for most animals (use this for humans too). Sagittal (L/R), frontal (feet on bottom, back on top), and transverse (cross section)
