BIOLOGY 1M03 Lecture Notes - Lecture 4: Spalax, Sebaceous Cyst, Aniridia
Document Summary
Vestigial traits traits that have lost their ancestral function in a species but are still retained by that species ex. Human appendix, human coccyx, eyes of a blind mole rat, foot bones on a whale, pelvic spurs of a snake. Homology- a similarity that exists in species that was inherited from an ancestor. Genetic homology- a similarity among species in dna sequences, gene content, or other genetic attributes that are due to shared ancestry. Developmental homology- a similarity among species in embryonic traits that is due to shared ancestry. Evidence: gill pouch still present in chick, human and house cat embryo: brachial cleft cyst- congenital epithelial cyst that is derived from the brachial arches (normally reabsorbed during embryonic development, fish arches usually develop into gills. Turtle, human, horse, bird, bat, seal all have humerus, radius and ulna, carpals, metacarpals, phalanges.
