Evolutionary Biologist- Review OnlineHS: Biology A
Evolutionary Biologists What do Evolutionary Biologists study? What do they look for when they examine data?
Definitions Homologous Structures Physical structures in living things that infer common (homo = same) ancestry Examples: manus bones in the chicken wing, bat wing, and human hand Vestigial Organs A structure in living things that is a remnant of its evolutionary past that may (now) serve no function Examples: third molars (wisdom teeth), appendix
Homologous Structures The following homologous structures seen in each limb below include (from top to bottom) the shoulder joint, humerus, radius, ulna, and manus. How have the structures remained the same/imply relatedness? How have the structures changed? Has anything else changed?
Human Vestigial Organs Vestigial Organ Original Purpose of Organ Why we no longer need it Another animals use Wisdom TeethTo chew down plant material, or other raw foods, compensate for normal teeth loss Smaller jaws, so less teeth can fit. Different foods easier to chew/digest Cooking? Human ancestors and present day primates have larger jaws, and diet may be different from humans AppendixAid in the process of digestion of plant materials It no longer assists in the digestion process Storage, digestion by herbivorous (plant) diet Muscles to move earsMove ears to better hear potential threats Ability to turn our head on a horizontal plane To alert them to potential threats. (A monkeys head still cannot move on a horizontal plane)
Vestigial Organ Original Purpose of Organ Why we no longer need it Another animals use TailboneBalance, communication, prehensile limb Walk upright. We have appendages to pick-up object Support pelvic organs Nictitating MembraneA third eyelidTears Cleaning out the dust and other particles Faster reaction time. Eye Moisture Extra protection Body HairFor warmth Fluff up to appear bigger & avoid fights For grasping by children Loss of natural predation There are other ways to stay warm warms Human Vestigial Organs – contd
Your presentation Using all your research, work with your group of fellow Evolutionary Biologists to create this part of your presentation that you will share for a group grade. Consider using one slide per bullet to assure youve addressed everything. The following information (and/or diagrams for each) must be included in your power point: An explanation of what homologous structures are. An explanation of what vestigial structures are. Explain what an Evolutionary biologist does Address the fundamental question from the Evolutionary Biologist point of view: How does your research provide evidence that all living organisms have common ancestry but have changed across time?