Mammals Lecs 1 (NOT FINISHED YET)

Where and when did Mammals originate?

Triassic, 200 mya

Is Triassic part of Mesozoic (?)(idk if i need to know this)

Yes

Look at pie chart on laptop where i can download it cause its messed up on slides etc

….

How many extant species are there? (Mammals?)

6,718 species

What are Extant species?

Now living, today

How many extinct species? (Mammals(?)

>4,000 genera

Extant species: number of genera, families, orders (ASK PROF IF I NEED TO KNOW THIS and also HOW TO STUDY go to OH!)

1,351 genera

167 families

27 orders

What are characteristics of Mammalian

1. Endothermy

2. Hair

3. Skin glands

4. Ears with pinnae

5. Solid endoskeleton (dentition, brainwash, etc)

6. Muscular diaphragm to … (supply negative pressure to lungs)

7. 4-chambered heart with well-separated chambers, a double-pump system

8. Anucleate red blood cells

9. Viviparous (most, some exceptions)

What is endothermy?

HEAT FROM WITHIN

Endothermic organisms generate heat from within by combustion of food.

Ectothermy

External heat…

Heterothermy

Other/different …

Poikilothermy

Variable …

Homeothermic

Constant body temp

Hair in mammals _____

Varies

Skin gland examples and purpose

Mammary, sweat, musk

Serve to produce oils, scents, facilitate cooling

Ears with pinnae

??

Solid endoskeleton means:

Lightweight, well ossified, strong

+Large braincase

+limbs beneath the body (generally) compared to reptiles where its splayed out

+Differentiated dentition TEETH ie many types

+Teeth are diphyodont and thecodont

+teeth have extreme diversification

+Determinant growth of bones

+Vertebral column highly differentiated and diversified

+Secondary palate

+EAR BONES …

+simplified and stronger lower JAW

+den tray-squamosal articulation

+well developed HOLLOW HOLES in skull = auditory bullae