Key Characteristic of notochords
- Anus develops from the blastospore and the mouth from a second opening
- Can spew from both ends
Key characteristics of Echinodermata
- Ring canal connects to the eusphogus
- Branches into 5
- separate sexes
Members of Echinodermata
All October Eskimos Hate Cold
Aestroidea -Starfish Ophiuroidea -Brittlestars Echinodea - Sea urchins/sand dollars Holothuroidea - Sea cucumbers Crinoidea - Sea lilies and feather stars
Key Characteristics of Chordata
- Notochord
- Dorsal nerve cord
- Slits or clefts
- Muscular post anal tail
What are gnathostomes?
Jawed vertebrates!
Members of Gnathostomes?
Two types of fish:
- Chonrichthyians (cartilaginous)
- Osteichthyes ( Bony fish)
Chonrichthyians members
Sharks, skates, rays, chimeras
How shark eggs develop?
3 ways
Oviparous - Outside
Ovoviparous - inside embryo in uterous
viviparous - inside embyro in uterus but connected by placenta
Osteichthyes members?
Ray finned fish
lobe finned fish
Osteichthyes: fish characteristics
- Bony endosketeton
- Vertebrates
- Breathe through operculum
- Swim bladder (buoyancy)
Tetrapods characteristics (eg) Amphibians
Four limbs with digits
Ears for detecting sound
Derived characteristics of vertebraes
- Vertebrae enclosing a spinal cord
- Elaborate skull
- Fin rays in aquatics
What are aminotes?
Include: Reptiles, birds and mamals
- Amphibians split 350 mya
First major group of reptiles
Parareptiles
Two main lineages of Diapsids
Lepidosaurs
Archosaurs
Members of lepidosaurs
lizards, snakes, tuataras
Members of archosaurs
Crocodiles, dinosaurs, pterosaurs, birds
Major adaptations of brids?
- lack of a bladder
- one ovary
- small gonads
- loss of teeth
When and what did birds derive from?
- 150 mya
- Derived from theopods
What differentiates mammals in the aniote clade?
- Mamary glands - produce milk
- Large brain
- Hair
- Differentiated teeth
What did mammals evolve from?
Synapsids
What lineages of mammals emerged by the cretaceous period?
Monotremes, Marsupials, eutherians
Monotremes?
- Egg laying mammals
eg) platypus
Marsupials?
- Develop in mother’s placenta
- Embryonic development while in a maternal pouch
