BIOL 190 Lecture Notes - Lecture 34: Tiger Salamander, Irish Elk, Bone Morphogenetic Protein 4
Document Summary
Traditional studies focussed on comparative embryology how embryos progress through development. How this differs among species: more recently. Adult phenotype is a product of environment and selection. Ex: one allele may cause a plant to grow taller at lower elevations and a different allele may grow taller at higher elevations. Reasons for interest minor changes in regulatory genes can have major effects on phenotypes. Development may constrain morphological evolution: many structures are uniform and repeated. Individualization causes these common repeated forms to become specialized. A difference in the timing or rate of developmental events. In some cases, salamander may retain gills and juvenile state. Horses have deepened their lower jaw, allowing them to eat more grass. Caused by expanding time that lower jaw bone is grown. The human head grows much smaller than the rest of the body. Antlers spanned 10 ft: mass of 100 lbs. Size of antlers is predicted from skull size.