LIFESCI 1 Lecture Notes - Lecture 24: Clavicle, External Fertilization, Convergent Evolution
Document Summary
Salmon, yellowfin tuna, common seahorse, fine0spotted moray eel, red lionfish. Anadromous (salmon) spend most of their lives in ocean then go back to freshwater to reproduce. Protogyny-> sex change from female to male (sheephead species) Protandry -> sex change from male to female. Can crawl around using fins & go to surface and gulf air through lung-like organs. Can live in very little to no water, burrow themselves in mud and stay moist until the lake fills back up. A neck, allows separate movement of the head. Fusion of the pelvic girdle to the backbone. The absence of gills (except some aquatic species) Tiktaalik, nicknamed a fishapod, shows both fish and tetrapod characteristics. Ribs to breathe air and support its body. Fins with the gone pattern of a tetrapod limb. Gas exchange organs-allows for more aerobic activity in land environment. Amphibians form 3 distinct clades: frogs & toads, salamanders, caecilians. Water to land transition: external vs. internal fertilization.
