gel_lec_19

gel_lec_19 - Lecture 19 – 2/26/10 Origin of Mammals: what...

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

View Full Document Right Arrow Icon

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

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

Unformatted text preview: Lecture 19 – 2/26/10 Origin of Mammals: what are we, where did we come from, and when? What are mammals? Three groups to make up mammalia- Placentalia- Marsupialia- Monotremata Monotremes- Only live in Australia- Lay eggs- Babies drink milk- Almost extinct Marsupials- Do well around the world- Settle in Australia- Have pouches- Tiny babies Placentalia- Have placenta to make baby stronger and larger Most mammal fossils can’t be traced into cretaceous (except possibly opossum group) Mammals probably first appeared middle Jurassic, around the same time as birds What characters do mammals have? Features seen in mammals- Only one bone in the lower jaw- Three year ossicles (reptiles only have one)- Secondary palate + nasal turbinate- “erect” posture- Mammary glands – suckling- No “third eye” Locomotion, food processing, senses, metabolism What are mammalian “ancestors”? Pelycosaurs: look more reptilian; carboniferous Therapsids: more mammalian; permian Cynodonts: more mammalian; shorter tail; some even had lumbar area (w/o ribs); had one huge bone in...
View Full Document

This note was uploaded on 08/30/2011 for the course GEL 3 taught by Professor Motani,r during the Spring '08 term at UC Davis.

Page1 / 2

gel_lec_19 - Lecture 19 – 2/26/10 Origin of Mammals: what...

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