Mammalia

Mammal Evolution Mammals are believed to have evolved from Reptiles during the late Triassic period: 200 mya

Mammal Evolution The first true mammal was a small, shrew-like organism that coexisted with Dinosaurs: Small to avoid predators and nocturnal –Ex. Hadrocodium fossil found in Northern China in 2002

Mammal Evolution Mammal’s inner-ear bones probably evolved from modified ancestral reptile jaw bones Has better hearing for a nocturnal lifstyle

Where did the ancestral mammal originate from? /how/index.htm

Based on the website just viewed where did the ancestral mammal originate from? How did the earth change over time? How could this have changed the environment? Could this environmental change cause a change in the type of species found?

The Synapsids Many synapsids had features considered characteristic of mammals, not reptiles.: Synapsids are the original ancestor of mammals

Synapsids Synapsids have 1 temporal openings reptiles have two Synapsids have different types of teeth, reptiles do not

How do you get from a reptile like mammal to a mammal ?

Using the cladogram on the following slide answer the following questions: 1. What organisms are most closely related to placental mammals?________________________ 2. What are the three types of mammals? ______________,_______________,____________ 3. What organism is least related to mammals?________________ 4. What is the ancestor of all mammals?__________ 5. What do you think the ancestor look like? (hint look back at your notes)_____________

Macroevolution

The Evolution of Mammals: Complete the worksheet