BIO153H5 Lecture Notes - Lecture 13: Diacodexis, Million Years Ago (Song), Marine Mammal
Document Summary
We know something was walking on land 395 million years ago. One of the few fossils that shows an animal walking (shows footprints) Walking on land came with modified limbs (cid:455)ou"ll o(cid:374)l(cid:455) (cid:271)e su(cid:272)(cid:272)essful li(cid:448)i(cid:374)g o(cid:374) la(cid:374)d if (cid:455)ou ha(cid:448)e a(cid:374) effi(cid:272)ie(cid:374)t (cid:449)a(cid:455) of (cid:373)o(cid:448)i(cid:374)g. For efficient movement, you need modified limbs that are specialized for the lifestyles that you live. Tiktaalik show the first evidence of wrist bones, so it probably had more adaptations that allowed it to walk better on land (wrist bones allow them to adjust their limbs to the environment) Tiktaalik also has interesting eyes; they resemble those of crocodiles, whom lie underneath water and have their eyes in positions that allows them to see from these positions. The actinistian lineage has characteristics linking it to its terrestrial. Lobe-fins are an evolutionary step that allowed organisms like tiktaalik to develop the modified wrist-bones.
