Aves

1
Aves

• Read 632-642
• Hw 644 1-21
• Work on NR 5

2
Reminder

• Aves are in the phylum Chordata (vertebrata)
• Aves is a CLASS

3
Aves

• Examples
• Gulls, penguins, albatross, parrots, doves, etc
• Are warm-blooded (endotherm/homeotherm)
• winged
• Lay eggs
• Bipedal (walks on 2 legs)

4
Characteristics

• 4 chambered heart
• Contain unique digestive and respiratory systems
  adapted for flight.
• Excretion is done using a cloaca
• Brain is highly specialized and some are
  considered extremely intelligent
• Lightweight skeleton
• Toothless beak
• Hard shelled eggs
• feathers

5
Reproduction

• Sexual
• All lay eggs
• Internal fertilization using cloaca
• Males are ZZ and females are ZW (a system where
  the ovum determines sex, not the sperm)
• Typically monogamous perform biparental care
• Yolk of a bird egg is larger than a reptile egg

6
Unique traits

• Hollow bones
• Crop and gizzard for grinding of food due to lack
  of teeth
• High metabolism to aid flight energy
• 75 of air intake bypasses the lungs and are then
  used during exhalation
• Most have poor sense of smell
• Highly complex mating rituals
• Non-Darwinian selection

7
Crop Gizzard

• Also found in insects.
• Why in birds and insects but not other animals?
• Lack of teeth reduces ability to mechanically
  break down food.

8
Hollow bones

• Bones are as strong and can make up as little as
  5 of the total body weight of a bird.
• Human skeleton makes up about 14 of our total
  weight.

9
Historical birds

• Earliest bird is Archaeopteryx
• Some extinct species include
• Dodo
• Moa
• Terror birds

10
Major Orders

• Evolutionary Milestone feathers
• Within class Aves are many (27) orders
• Some examples are
• Falconiformes
• Passeriformes
• Casuariiformes
• Podicipediformes
• Piciformes
• Ciconiiformes