Deuterostomes Flashcards
(31 cards)
what are the shared derived characteristics in the deuterostome clade?
- radial, indeterminate cleavage
- coelom from archentron
- blastospore -> anus
describe Phylum Echinodermata
- “spiny skins”
- sea stars, sea urchins, sea cucumbers, sand dollar
- often 5-part symmetry
- endoskeleton (internal CaCO3)
what is the SDT for Echinodermata?
Water Vascular System
- network of fluid-filled canals
- feeding, gas exchange, movement
SDTs for Phylum Chordata
- Notochord
- Dorsal, hallow nerve cord
- Post-anal tail
- Pharyngeal slit/cleft
Basal Chordate (s)
Lancelet (Cephalochordate) and Tunicates (Urochordates)
- invertebrates
- marine suspension feeders
- 1 Hox cluster
what are the SDTs for Vertebrates
- bone or cartilage vertebrate that replaced notochord
- 2 + Hox clusters (result of complete genome duplication and increased genetic complexity - > more complex body plan)
- chordate character more evident in embryo
Basal Vertebrate (s)
Jawless Fish
- hagfish, lamprey
- cartilage
Gnathostome characteristic
Jaw-mouth
SDTs for Gnathostome
- hinged jaw
- bony skeleton
- 4 Hox Clusters - more complexity (from another genome duplication)
Basal Gnathostome (s)
Chondricthyes - cartilaginous fish (bone only in teeth and fin tails)
- ancestor had bone all over body
- DERIVED TRAIT of LOSING most bone
describe Osteichthyes
“bone fish”
named for ancestral bony skeleton - Calcium Phosphate
DT for Osteichthyes
Swim bladder (homologous with lungs)
Basal Osteichthyes
Actinoptyergii - ray-finned fish
SDTs for Lobe-Fins
Muscular fins/limbs for locomotion (includes all terrestrial vertebrates)
Basal Lobe-Fins
Actinisitia - coelcanths
Dipnoi - lungfish (lungs and gills)
SDTs for Tetrapods
- 4 limbs with digits
- neck
- fused pelvic girdle (efficiently transmits forces through body) [there’s no buoyancy on land!]
Basal Tetrapods
Amphibia
Terrestrial, but require moist environment
- eggs laid in water
- aquatic larva
- thin, moist skin
Ex. frogs, toads, salamanders
SDTs for Amniotes
- amniotic egg (amnion: membrane that forms fluid-filled sac around embryo) [allows for completely terrestrial life]
- ribcage ventilation (more efficient than through skin)
Reptilia
Phylum Amniotes, Sister Taxon to Mammals
- turtles, lizards, snakes, alligators
- shelled eggs laid on land
DTs of Mammals
- mammary glands
- give birth to live young (mostly)
- hair, fat layer under skin -> retain heat
what are the three groups of Mammals?
- monotremes
- marsupials
- eutharians
monotremes
Basal Animals
- lay eggs
- have hair
- produce milk, but no nipples
Platypus echidnas - only in Australia and New Guinea
marsupials
- give birth to live young
- have nipples
- born very early (complete their development while nursing, often in pouch)
- Placenta: structure for nutrient exchange from mother to embryo
Oppossums, Kangaroos, Koalas
Eutharians
- “placental mammals” - have complex placenta
- longer pregnancy than marsupials
- complete their embryonic development in uterus
