Plate tectonics Mammal Traits

Plate tectonics

positions of continents aren’t fixed; changed through geological time

Ocean floors/continents

positioned on 8 major lithospheric plates

Major lithospheric plates

“float” on a hot/dynamic asthenosphere

Subduction

lithosphere plates can collide/one can move underneath another

Orogeny

subduction causing mountains to form

2 major landmasses

laurasia/gondwana

Mammalia

1. Prototheria, 2. Metatheria, 3. Eutheria

Prototheria

Monotremes

Metatheria

Marsupials

Eutheria

Placentals

Non-fossilizable features/metabolism

Differences between living and mammals/reptiles (ex. mammary glands, suckling behavior)

Metabolism

1. Endothermy, 2. Body Hair, 3. sweat glands, 4. respiratory control

Cranial Anatomy

Only 1 bone forms each side of the jaw in mammals

Ear ossicles

3 small bones which transmit sound vibrations. Homologous

Brain differences

Brain size is much larger than expected in mammals

Cerebellum

controls movement/coordination

Neocortex

“higher level” thinking as well as receiving sensory input/producing appropriate behavioral response.

Incisors

in front. Harvesting

Canines

at corners of mouth. Puncturing

Premolars

between canines/molars

Molars

back of mouth. chewing/crushing

Dental formula

1. Upper incisors, 2. Upper canines, 3. Upper premolars, 4. Upper molars

Locomotor differences

limbs positioned underneath body, not sprawled as in reptiles