Ornithology

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Ornithology

• Basic Characteristics, Evolution of Birds, Form
  and Function,

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Intro/Basic Characteristics
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What are birds?

• Taxonomy
• Kingdom Animalia
• Phylum Chordata
• Class Aves

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Characteristics

• Bipedal
• Feathers (diagnostic)
• Insulation
• Lift and thrust
• Toothless bills covered with horny sheath
• Wings
• Ability to fly

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Characteristics (cont.)

• Adaptations associated with flight
• Skeleton
• Musculature
• Physiology
• Reproductive system
• CNS
• etc

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Adaptive Radiations (within adaptive radiations)

• Evolution of ecological diversity within a
  rapidly multiplying lineage (Schluter, 2000)
• 150-160 MYA
• gt10,000 species extant
• Fraction of what has existed

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• Ur bird ancestor

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Hawaiian Honeycreepers

• Radiations within smaller groups
• Radiation in body parts

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

• 29 orders
• 187 Families
• 2000 Genera
• 10000 species
• Rapidly changing

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Interesting biogeograpy

• Each faunal region has its characteristic birds
  endemics

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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)
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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
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1998
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Evolution of Birds
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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
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Based on shared, derived characteristics
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middle ear bones
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Diversity of Birds100,000 species!

• - Heritable variation in a population due to
  mutation
• - Some variation leads to differential
  reproductive success (if expressed)

Pg 47

• Due to
• Phyletic evolution
• Cladistic evolution (speciation)
• Extinction termination of a lineage

b
a
c
c
b
c
b
d
b
Time
a
a
a
a
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Shared, derived characters with anything?
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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

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Link Between Birds and Reptiles

• Lots of morphological, behavioral and
  physiological similarity between Reptiles and
  Birds.
• Which reptiles???

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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

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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

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Could it fly?
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The historical evolution of flight debate

• Two main hypotheses
• Ground-up (cursorial hypothesis)
• Trees-down (arboreal hypothesis)

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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

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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 (Feduccias study)
• Large attachment sites for downstroke on humerus
  but no keeled sternum
• Flying squirrels?

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Winner?

• Trees-downmaybe
• 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

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Craniate phylogeny and diversity of living
species From Bemis http//www.bio.umass.edu/biolog
y/bemis
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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

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Fig. 3.25
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Fig. 3.20
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Alternative Hypotheses?

• Overhead from Feduccia

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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

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Form and Function
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Feathers

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

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Feather Development
Lizard scales
Bird 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

Scaleless hen
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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

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Feather morphogenesis

• Movie

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Morphology of a Feather
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Morphology of a feather (cont)
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Morphology of a feather (cont)

• Major Types
• Contour
• Insul., Flight
• Vanes symmetrical
• Vanes asymmetrical
• Semiplumes and
• Rachis gt barbs
• Down
• Rachis lt barbs
• Insul.
• Adult down
• Natal down (lost)
• Powder down
• Grooming
• waterproofing
• Bristles
• Little or no vane
• Filoplume
• Monitor pennaceous feathors

Pennaceous
Plumulaceous
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Contour feathers

• Wings

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Contour feathers

• Tail

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Semiplume

• ostrich

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Down
natal
powder
adult
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Filoplume
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Bristles

• Whip-poor-will

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Cross-section of feather follicle

1. Barb ridges of epithelial
2. Surrounding dermal core of connective tissue
3. Space of the follicle
4. Epithelial tissue of follicle
5. Associated musculature

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Melanins
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Carotenoids
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Porphyrins
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Structural colors