1. Comparative Anatomy Higher Amniotes
Note Set 4
Chapter 3

2. Characteristics of Birds
Feathers present
Homeothermic
Single occipital condyle
Scales on legs and feet
Figure 6.1

3. Flier and Flightless Birds
Archeopteryx- glider
sternum
Figure 6.2: (a) Archaeopteryx (b) pigeon.

4. Classification Modern birds- Subclass Neornithes
Ancient birds- Subclass Archeornithes
Passeriformes- Largest order of birds
Birds arose in mid-Jurassic Period (ca. 175 mya)

5. Mammals Mammals arose in mid-Triassic Period Cenozoic- age of mammals
Quaternary and Tertiary
Synapsid lineage began with pelycosaurs, which therapsids succeeded
Therapsids gave rise to mammals
Figure 6.3.

6. Therapsids Synapsid skulls Possess hair and mandible
Heterodont dentition
Fusion of two bones
Single lower jaw bone (dentary)

7. Evolution of Reptiles 1. Reduction in number of bones
2. Fusion of bones
In reptiles, articular bone articulates with quadrate
In mammals, dentary articulates with squamosal
Figure 6.4: Mandible cladogram.

8. Evolution of Mammalian Jaw
Articular of lower jaw and quadrate of upper jaw and skull become middle ear bones: maleus, incus and stapes
Figure 6.5: Jaw and middle ear bone evolution.

9. Middle Ear Bones Articular and quadrate evolved from 1st visceral arch
Figure 6.6: Origin of middle ear bones; adult (left) and embryo (right).
Articular and quadrate evolved from 1st visceral arch
Stapes evolved from hyomandibular of 2nd arch
Eustachian tube from 1st pharyngeal pouch

10. Figure 6.7: Skeletal Derivatives of Pharyngeal Arches.

11. Phylogeny of Mammals Oviparous- egg layers
Therapsids and all birds
Viviparous- give birth to live young
Most mammals
Ovoviviparous- retain eggs in body and give birth to live young
Many fish and reptiles
Figure 6.8: major categories of living mammals .

12. Placental Type
Therians diverged into the metatheria (marsupials) and eutheria (placental mammals) orders
Metatheria- yolk sac placenta
Eutheria- true placenta
chorioallantoic placenta

13. Characteristics of Mammals
Hair
Single dentary bone
Fused to form mandible in primates
Sweat glands
Mammary glands
Homeotherms
Enucleated RBC

14. Figure 6.9: Eutheria (placenta mammals) phylogeny

15. Orders in Class Mammalia
Infraclass Ornithodelphia:
Monotremata- egg layers
Infraclass Metatheria:
Marsupialia- marsupium present
Infraclass Mammalia:
Artiodactyla- Even-toed ungulates
Perissodactyla- Odd-toed ungulates
Rodentia- Largest groups of placental mammals
Primates- catarrhine (Old World monkeys and humans) and platyrrhine (New World monkeys)

16. Suborder Anthropoidea -Infraorder Platyrrhini
-Infraorder Catarrhini
Two infraorders distinguished
by nose form
Platyrrhines
Nostrils flare to sides
Flat nose
Wide septum
New World monkeys and marmosets
Catarrhines
Nostrils point straight down
Narrow septum
Old World monkeys, apes, and humans
(a)
(b)
Figure 6.10: Platyrrhine (a) and catarrhine (b).

17. Literature Cited
Figure
Figure 6.2, 6.3, 6.4, 6.7, & 6.8- Kent, George C. and Robert K. Carr. Comparative Anatomy of the Vertebrates. 9th ed. McGraw-Hill, 2001.
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