Bio; Lecture 22; Survey of the Animal Kingdom

Bio; Lecture 22; Survey of the Animal Kingdom - Principles...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Principles of Biology 2 BIO U103 March 12, 2007 Vertebrates o Phylum: Chordate o Origin o May have evolved from urochordates via paedogenesis o Cephalochordates may have given rise to vertebrates—fossil and molecular evidence supports this o All vertebrates have a backbone o Some fish however, have a cartilage skeleton o Benefits of having an Endoskeleton o Locomotion is much more efficient because of muscle-bone attachments o Endoskeleton grows with the organism; it doesn’t need to be shed. o Provides a reservoir of calcium and phosphate o Enables organisms to become terrestrial—provides support o Evolution o May have either a tunicate (urochordate) larva-like ancestor, or a lancelet- like (cephalochodate) ancestor. o Evolved into a jawless fish with a cartilage endoskeleton, such as sharks o Evolved into jawed, boney fish with an endoskeleton Could open and close their mouth. o Tetrapod (4 legged) Fish that were able to get out of water and go onto land briefly Had lobed fins that enabled terrestrial locomotion Bones in fins; limb-like Some also have lungs that enable them to breath Mud puppies Some have eyes on top of their head, instead of on the side Tetrapods are fish-like Have fins, scales, and primitive jaws Also are reptile-like Have a separated neck Wrists Flat head Expanded ribs o Land Colonization (new features) Reorganization of skeleton and muscles
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/26/2008 for the course BIO 103 taught by Professor Potts-santone during the Spring '07 term at Northeastern.

Page1 / 4

Bio; Lecture 22; Survey of the Animal Kingdom - Principles...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online