BILD 3 Lecture Notes - Lecture 7: Flightless Cormorant, Mexican Tetra, Canine Tooth
26 Oct 2018
School
Department
Course
Professor
Document Summary
Cave tetra lost pigment, contain scales over eyes, and eyes are smaller. They cannot use their eyes, but the presence of the eye is because an ancestor used to have it and use it: ex: many birds have wings, but cannot fly. Many of these species live on islands that do(cid:374)"t ha(cid:448)e (cid:373)a(cid:374)(cid:455) predators, so they use a more energy-efficient means of moving: walking. However, if a predator is introduced, these birds cannot escape, so many of these species have become extinct: penguin wings are not vestigial structures because penguins still use their wings (for underwater swimming). May not be for flight, but wings still have function. Vestigial structures are functionless: human goose bumps: muscles attached to hair follicles contract, making hairs stand up; occurs when we get cold or scared. We have this mechanism because we descend from animals with lots of fur, who use this as a defense mechanism and way of insulation.
