Chordate Diversity 2

Chordate Diversity 2 - Chordate Diversity 2 Class Amphibia...

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

View Full Document Right Arrow Icon
Class Amphibia - Frogs, salamanders, newts, etc (Ca. 4,800 spp). - Lungs primitive, respiration aided by highly vascularized moist skin (gills in juveniles) - Fertilization external; needs water; juveniles aquatic (limits range expansion) Next major milestone is the evolution of amniotic egg. IAmniotes) - Evolution of internal fertilization - Amniotic egg - Extra-embryonic membranes - Amnion: protects and provides shock absorption - York sac: stockpile of nutrients for the embryo - Allantois: disposal sac for wastes; also functions as a respiratory organ - Chorion: functions as a respiratory organ (gases diffuse freely across shell) - Rise of the Amniotes - Fertilization infernal - Independence from water (egg safety) - Evolutionary trend towards rearranging limbs below body - Can support their own weight, unlike human baby because we have big heads - Breaks off into two groups, reptiles and humans. Reptiles
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 09/21/2011 for the course BSC 2010 taught by Professor Bowes during the Spring '08 term at University of Florida.

Page1 / 3

Chordate Diversity 2 - Chordate Diversity 2 Class Amphibia...

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