Chordates 2: Tetrapods BIOL 1407. Amphibians Tetrapods Moist skin External Fertilization Eggs need water.

Chordates 2:Tetrapods

BIOL 1407

Amphibians

• Tetrapods• Moist skin• External

Fertilization• Eggs need water

Amphibians

• Aquatic larvae• Metamorphosis• Photo Credit of Tadpole: LiquidGhoul, 2008, Wikimedia Commons

Salamanders and Newts

Frogs and Toads

Caecilians

Reptiles

• Amniotes• Reproduce without

water • Internal Fertilization• Tough keratinized

skin• Scales and feathers

made of keratin• Photo Credit: Doyle Cross, 2008

Photo Credit of Red-throated Bee Eater: Tom Tarrant, 2008, Wikimedia Commons

Avian Flight Adaptations

• Forelimbs modified into wings

• Flight feathers

• Hollow bones

• Beak• No teeth

Photo Credit for Keel-billed Toucan: Supernova, 2006, Wikimedia Commons (originally posted on Flickr)

Avian Flight Adaptations

• Excellent vision

• Big brains• Tiny large

intestine• One ovary

Photo Credit for White-Crowned Hornbills: Snowmanradio, 2008, Wikimedia Commons (originally posted on Flickr)

Mammals

• Hair• Mammary Glands• Three middle ear

bones• Single lower jaw

bone• Differentiated teeth• Photo Credit: Eric Mas Casas, 2008,

Wikimedia Commons

Monotremes

• Lay eggs

• Mammary glands

• No nipples

• Echidnas

• Duck-billed platypus

Photo Credit: Peter Scheunis, 2005, Wikimedia Commons

Marsupials

• Young are born very early

• Finish development in marsupium = pouch

Photo Credit of Wallaby and Joey: Benjamint444, 2008, Wikimedia Commons

Photo Credit of Numbat: Gnangarra, 2006, Wikimedia CommonsPhoto Credit of Wallabies: Roland Zumbühl, 2004, Wikimedia Commons

Eutherians = Placental Mammals

• Placenta to nourish young within uterus

• Born at late stage of development

• Photo Credit: Nevit Dilmen, 2008, Wikimedia Commons

Photo Credit: John Storr, 1997, Wikimedia Commons

Photo Credit: John Storr, 1997, Wikimedia Commons

The End

Unless otherwise specified, all images in this presentation came from:

Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.Slide #18 is from 7th edition, Campbell, et al.