click below
click below
Normal Size Small Size show me how
Tetrapods
Bio Midterm 2
Term | Definition |
---|---|
Env of early tetrapods | -same time animals were "invading the land" -mainly gymnosperms (water dependent) -swamp habitats and very food rich |
evolution of tetrapods | -lungfish with fins were ancestors -pectoral and pelvic find homologous to fore- & hind- limbs -lungfish are sister group to tetrapods bc dna evidence |
tiktaalik and acanthostega | -found in cold regions -lived in tropical warm climates -fossils moved with tectonic plates |
genius tiktaalik | -around 375 m.y.a -"fishpod" -between fish & tetrapod (characteristics of both groups) |
tiktaalik trais | 1. primitive neck -allowed head movement 2. forelimb bones 3. had pelvic girdle but not good 4. had ribs |
genius acanthostega | -lived around 360 mya -mainly aquatic but first tetrapod -well developed pelvic and pectoral girdles |
acanthostega habitat | -benthic organism on bottom of pools -able to come on land and crawl |
traits of acanthostega | 1. well developed muscular laterally compressed tail 2. well-developed gills 3. relatively well developed legs (weight bearing) 4. had toes 5. weak ribs and small lungs |
Exaptation | -an organism possesses a trait that was used for one purpose, but happened to be useful for other purposes -suggests teleology but NO! |
exaltation examples | 1. evolution of tetrapods (legs evolved first before tetrapods moved to land) 2. feathers(originally used for insulation but now used for flight |
homologous | -similar position, structure, and evolutionary origin, but not same function |