1. Basic Characteristics, Evolution of Birds, Form and Function,
Ornithology
Basic Characteristics, Evolution of Birds, Form and Function,

2. Intro/Basic Characteristics

3. What are birds?
Taxonomy
Kingdom Animalia
Phylum Chordata
Class Aves

4. Characteristics Bipedal Feathers (diagnostic)
Insulation
Lift and thrust
Toothless bills covered with horny sheath
Wings
Ability to fly*

5. Characteristics (cont.)
Adaptations associated with flight:
Skeleton
Musculature
Physiology
Reproductive system
CNS
etc…

6. Adaptive Radiations (within adaptive radiations)
Evolution of ecological diversity within a rapidly multiplying lineage (Schluter, 2000)
MYA
>10,000 species extant
Fraction of what has existed

7. Ur bird ancestor

8. Hawaiian Honeycreepers
Radiations within smaller groups
Radiation in body parts

9. A note on Avian Classification
Imprint of Linneaus 1758
Binomial nomenclature
Upupa epops
Standard English Names (“Common Name”)
In NA, both established by AOU
Kingdom
Phylum
Class
Order
From
Genus
species
species
Genus

10. Classification of three species of woodpeckers
Taxon
Downy Woodpecker
Hairy Woodpecker
Northern Flicker
Class
Aves
Order
Piciformes
Family
Picidae
Genus
Picoides
Colaptes
Species
pubescens
villosus
auratus

11. Current Classification
29 orders
187 Families
2000+ Genera
species
Rapidly changing

13. Interesting biogeograpy
Each faunal region has its characteristic birds – endemics

14. Biogeography (cont.) Regions Endemic (non-passerines)
Representative Family Radiation
Holarctic
Incl. Nearctic and Palearctic
Loons, (Gaviidae)
Auks (Alcidae)
Accentors (Prunellidae)
NW warblers (Parulidae)
OW warblers (Sylviidae)
Neotropical
Rheas (Rheidae)
Sunbittern (Eurypygidae)
Motmots (Momotidae)
Hummingbirds (Trochilidae)
Tyrant-flycatchers (Tyrannidae)
Ethiopian
Ostrich (Struthionidae)
Turacos (Musophagidae)
Woodhoopoes (Phoeniculidae)
Larks (Alaudidae)
Sunbirds (Nectariniidae)
Oriental
None
Leafbirds (Irenidae)
Pheasants (Phasianidae)
Flowerpeckers (Dicaeidae)
Australasian
Emus (Dromiceidae)
Kiwis (Apterygidae)
Monarch-flycatchers (Monarchidae)
Birds-of-paradise (Paradisaeidae)

15. Biogeography (cont.)
Most bird communities or faunas are mosaics of species of various ages from various historical backgrounds
+ factors affecting species richness
Immigration / Invasion
Stochastic extinction events
Regional
Bird Community
Local
Bird Community
Speciation
Habitat
selection
Competitive exclusion
From Ricklefs and Miller, 2000
Mass extinction events
Predatory exclusion

16. 1998

17. Evolution of Birds

18. Note on Phylogenetics
Phylogenetics – History of the evolution of a group
Cladistics – defining groups based on shared characteristics not found in ancestors (derived)
Cladogram – “tree-like” hypothesis of the hierarchical evolutionary relationships of a group A C D E F
OTUs
Tips
Nodes
Branches
Extinct taxa
Speciation
“Reading” the tree B
time

20. Based on shared, derived characteristics

21. middle ear bones

22. Diversity of Birds 100,000 species!
Pg 47
- Heritable variation in a population due to mutation
- Some variation leads to differential reproductive success (if expressed)
Due to :
Phyletic evolution
Cladistic evolution (speciation)
Extinction – “termination of a lineage” c b a c b c b d b
Time a a a a

23. Shared, derived characters with anything?

24. Other features? Nucleated RBCs Scales
Ankle in tarsal bones (not between long bones and tarsals)
Bipedal (theropods)
Yolked, polar, cleidoic egg
Females are heterogametic
etc…

25. Link Between Birds and Reptiles
Lots of morphological, behavioral and physiological similarity between Reptiles and Birds.
Which reptiles???

26. Founding of Archaeopteryx
Lithograph Quarrymen – Jurassic limestone
Single feather impression – 1861, Bavarian Quarry
Complete skeletal impression – Few months later
2nd complete skeleton – 1877, quarry near Eichstatt, Germany
Herman von Meyer
Archaeopteryx lithographica

29. Archaeopteryx Debates Support of Darwinian evolution
Darwin predicted transitional fossils in 1859
‘one of the best links between two taxa’ (Feduccia, Ostrom, etc.)
Creation / Evolution debate (pg 27)
Evolution of feathers (flight or insulation first?)
Evolution of homeothermy in birds
Evolution of flight
Ground-up vs. Trees down

30. Could it fly?

31. The ‘historical’ evolution of flight debate
Two main hypotheses:
Ground-up (cursorial hypothesis)
Trees-down (arboreal hypothesis)

32. Ground-up Assume biped, cursorial ancestor
Has to be bipedal to use wings at all
Large legs for running muscle attachment
Bones of legs are long
Once running:
Use feathers for other things
Catch insects
Pick up minimum speed for lift: Flight

33. Trees-down Assume semi-bipedal leaping and gliding ancestor
Use of claws to scale trees, then glide to ground
Claws retained in winged appendages
Short hand wing (power), relatively long arm wing (lift)
Claw geometry (Feduccia’s study)
Large attachment sites for downstroke on humerus but no keeled sternum
Flying squirrels?

34. Winner? Trees-down…maybe Largely historical debate More productive???
Why evolve flight?
To help escape from predators
To help catch flying or speedy prey
To help move from place to place (leaping or gliding)
Vigilence
Migration, etc…
Nomadism
To free the hindlegs for use as weapons

36. and diversity of living species From Bemis
Craniate phylogeny
and diversity of living species
From Bemis

37. 1/31/06 Lab tomorrow – in the field (Briar Creek Lake) Bring
Clothes
Binoculars
Waterproof notebook
Time to meet?
Lab Activities BWSV
Read Taking Field Notes Handout
Lecture Today
End Evolution
Start Form and Function
Feathers

38. Fig. 3.25

41. Fig. 3.20

42. Alternative Hypotheses?
Overhead from Feduccia

43. Leading alternative hypotheses
Theropod Ancestry
Pros
Lots of fossils
Some with feathers
Bone morphology
Foot with 3 digits
Embryology (birds w/5)
Sholder joint similarity
Facilitates wings held at sides
Eggs in nest structure
Cons
Theropod adapted for running (how could flyer and runner share ancestry?
Feathers? (Old argument)
Theropod fossils – yes
Used for insulation
Exapted for flight.
Thecodont Ancestry
Pros
Tree dwellers
Glider forms
In the trees
“More parsimonious argument that flight feathers evolved from gliding stabilizers rather than insulation”
Cons
Fossil Evidence is missing

44. Form and Function

45. Feathers Most conspicuous integumental derivative Keratin Function
Flight
Heat Conservation
Reduced convective and evaporative heat loss
Increased insulation

46. Feather Development
Bird scales
Lizard scales
Development triggered by an interaction b/w epidermis and dermal mesenchyme
Formation of dermal papilla (placode)
Mitotic divisions in a collar zone of the stratum germinativum near the base of the papilla form a crown of barbs
Covered by a horny sheath of epidermis
Inductive interaction between the epidermis and the dermal mesenchyme
Leads to a formation of a dermal papilla
Mitotic divisions in the stratum germinativum near the base of the papilla form a crown of barbs
Covered by a horny sheath of epidermis
Cells on one side of the of the papilla divide more rapidly than others
Formation of shaft that extends upward carrying the barbs that are formed in the collar
The base of the feather recedes into the skin with layers of epithelial cells that form the feather follicle
Scaleless hen

47. Feather Development As development proceeds:
Differential cell division on one side of the papilla
Timing of expression of two proteins: Shh & Bmp2
These cells form a shaft away from the body
carrying the barbs that are formed in the collar
The base of the feather recedes into the skin
Accompanied by layers of epithelial cells
Feather follicle
Degeneration of epidermal sheath

48. Feather morphogenesis
Movie

49. Morphology of a Feather

50. Morphology of a feather (cont)

51. Morphology of a feather (cont)
Major Types:
Contour
Insul., Flight
Vanes symmetrical
Vanes asymmetrical
Semiplumes and
Rachis > barbs
Down
Rachis < barbs
Insul.
Adult down
Natal down (lost)
Powder down
Grooming
waterproofing
Bristles
Little or no vane
Filoplume
Monitor pennaceous feathors
Attached to sensory corpuscles
Pennaceous
Plumulaceous

52. Contour feathers
Wings

53. Contour feathers
Tail

54. Semiplume
ostrich

55. Down
natal
powder
adult

56. Filoplume

57. Bristles
Whip-poor-will

58. Cross-section of feather follicle
Barb ridges of epithelial
Surrounding dermal core of connective tissue
Space of the follicle
Epithelial tissue of follicle
Associated musculature
This slide displays an avian feather follicle in cross section. Notice the barb ridges of epithelium surrounding a core of areolar connective tissue. Observe that the feather follicles are surrounded by dense connective tissue, which is part of the dermis. Thus, feather follicles are within the dermis. Also take note of the muscles surrounding each feather follicle. These are feather muscles which control the positioning of feathers.

59. Melanins

60. Carotenoids

61. Porphyrins

62. Structural colors