Lecture 6 Flashcards
Which Phyla from the animal Kingdom have a backbone?
Chordata
What do all Tetrapods have in common?
They are all four-limbed vertebrates
Different animals living similar lifestyles may result in _________________
Evolutionary Convergence
Where animals show homologous structures
This does not suggest close evolutionary relationships
Structures that have no or lesser apparent function and appear to be residual parts inherited from a distant ancestor
Vestigial structures
e.g Tail bones in Humans
Pelvic girdle in snakes
The first tetrapods arise from one group of Devonian freshwater _______________
Lobe-finned Fish
Have articulated bones within their fins. They also had both gills and lungs.
These fish could walk from a dried out water body to a fresh water body using their lungs to breathe
A lobefinned fish that began to show amphibian characteristics
Tiktaalik - A transitional species from the end of the Devonian age
_____ Evolved from amphibian ancestors
Reptiles
Key evolutionary novelties of the reptiles include______
Skeletal modifications for terrestrial locomotion and development of an amniotic egg (laid on land) as opposed to amphibians who lay their legs in water.
Reptiles are classified into 4 groups based on the openings behind the eye sockets (orbits) called ____________
Temporal fenestra
The 4 different groups of openings behind the eye sockets are
Anapsids
- Turtles
Euryapsids
- icthyosaurs, plesiosaurs
Synapsids
- includes the sail-finned Dinetrodin and the therapsids (mammal like reptiles
Diapsids
- All other reptiles including dinosaurs
Diapsid reptiles are divided into:
Lepidosaurs ( the lineage that leads to modern lizards and snakes)
Archosaurs ( two lineages: crocodilian called pseudosuchia and another called avemetatarsalia which includes the pterosaurs and dinosaurs
Key evolutionary novelties of the archosaurs include
changes to the ankle that allowed for semi upright (pseudosuchia) and fully upright postures (avemetatarsalia)
____________ include dinosaurs and pterosaurs (sister clade to the dinosaurs).
Avemetatarsalia
________ are known from rare fossils in strata from the Late Triassic through to the end of the Cretaceous (228-66 m.y.a)
Pterosaurs
They ranged in size from very small to massive in size. One of the largest lived at the end of the Cretaceous in North America (Quetzalcoathus)
Vertebrate palaeontologists employ_______ in assigning phylogenies (evolutionary relationships)
Cladistics
