- Image of the lynx received from [ [http://wallpaperswiki.org/felidae-lynx/] on [5/15/15] by [ HQ Wallpapers for PC]
- Image of Rhino. Iguana received from [http://www.lizardtypes.com/rhinoceros-iguana/] on [5/15/15] by [Lizard Types]
- Image of falcon received from [http://hdontap.com/index.php/video/stream/live-peregrine-falcon-cam] on [5/15/15] by [HDonTap]
- image of jaguar received from [http://www.taringa.net/post/ecologia/16824378/Animales-en-peligro-de-extincion.html] on [5/15/15] by [Tariga]
- Image of panther chameleon received from [http://pixshark.com/panther-chameleon.htm] on [5/15/15] by [Pixshark]
- Image of frog received from [http://www.futuretimeline.net/resources/energy-environment.htm] on [5/15/15] by [Future Timeline]
- Image of salamander received from [http://calphotos.berkeley.edu/cgi/img_query?stat=BROWSE&where-lifeform=Amphibian&where-taxon=Ambystoma+laterale&title_tag=Ambystoma+laterale] on [5/515/15] by [BSCIT]
- Image of a toucan received from [http://www.weesk.com/redim-man-04-toucan] on [5/15/15] by [Weesk Studio]
- Image of bird of paradise received from [http://aboutpetbirds.com/bird-species/birds-of-paradise.html/attachment/bird-of-paradise-3] on [5/15/15] by [keenan]
- Image of a dorsal hollow nerve cord received from [http://science.kennesaw.edu/~jdirnber/Bio2108/Lecture/LecBiodiversity/BioDivAnimals.html] on [5/17/15] by [http://science.kennesaw.edu/]
- Image of notochord diagram received from [http://www.bio.miami.edu/dana/107/107F11_4.html] on [5/17/15] by [http://www.bio.miami.edu/]
- http://www.britannica.com/EBchecked/topic/420637/notochord
- http://www.britannica.com/EBchecked/topic/626589/vertebral-column
- Image on gill slits received from [http://dtc.pima.edu/blc/182/lesson1/1step3/1step3page2.htm] on [5/17/15] by [http://dtc.pima.edu/]
- https://www.boundless.com/biology/textbooks/boundless-biology-textbook/vertebrates-29/chordates-171/characteristics-of-chordata-663-11884/
- http://www.biology-online.org/dictionary/Chondrichthyes
- Image of ray received from [http://imgarcade.com/1/class-chondrichthyes-examples/] on [5/17/15] by [imgarcade]
- image of shark received from [http://mtrip.weebly.com/geography.html] on [5/17/15] by [ Mike's Travels]
- Image of whale shark received from [http://imgbuddy.com/class-chondrichthyes.asp] on [5/17/15] by [imgbuddy]
- www.biology-online.org/dictionary/Osteichthyes
- Image of lion fish received from [https://www.studyblue.com/notes/note/n/untitled-flashcards/deck/10574918] on [5/17/15] by [STUDYBLUE]
- Image of flame angle received from [http://www.bluereefaquatics.com/product/flame-angelfish/] on [5/17/15] by [Blue Reef Aquatics]
- Image of Emperor fish received from [http://commons.wikimedia.org/wiki/File:Pomocanthus_imperator_Emperor_Angelfish_by_Nick_Hobgood.jpg] on [5/27/25] by [Nick Hobgood]
- Image of tree frog received from [http://animal-kid.com/pictures-of-amphibians-for-kids.html] on [5/17/15] by [http://animal-kid.com/]
- Image of dart frog received from [http://www.darwinsgalapagos.com/animals/amphibia_amphibians.htm] on [5/17/15] by [Darwin's Galapagos]
- http://www.shsu.edu/~bio_mlt/AMPHIBIA.html
- Image of snake received from [http://dvbiology.org/biologyweb/zosnake.htm] on [5/17/15] by [http://dvbiology.org/]
- Image of tortoise received from [http://www.mojavenp.org/Gopherus_agassizii.htm] on [5/17/15] by [Mojave National Preserve]
- http://marinelife.about.com/od/vertebrates/p/ClassReptilia.htm
- http://www.eoearth.org/view/article/150031/
- Image of Blue Jay received from [http://creativefan.com/30-majestic-bird-photos/] on [5/18/15] by [Creative Fan]
- Image of polar bear received from [http://www.hdwallpapersnew.net/polar-bear-desktop-wallpapers/] on [5/18/15] by [Admin]
- Image of lion received from [http://funcrisp.com/2015/03/13/20-stunning-pictures-of-lions/] on [5/18/15] by [Fun Crisp]
- Image rhino received from [http://www.itsnature.org/endangered/black-rhinoceros/] on [5/18/15] by [Nature]
- http://www.scilogs.com/sankore_scriptures/the-amniotic-egg-an-adaptation-to-land-life/
- http://nationalzoo.si.edu/Animals/ReptilesAmphibians/cold_blooded.cfm
- http://www.britannica.com/EBchecked/topic/498684/reptile/38472/Circulatory-system
- http://reptilis.net/reptiles.html
- http://minerva.union.edu/linthicw/endo.htm
- http://www.ucmp.berkeley.edu/mammal/eutheria/placental.html