Transcript Birds - Green Local Schools

Birds
Chapter 42
Origin and Evolution of Birds
Section 42.1
Important characteristics
Feathers – only birds have them!
Wings – modified forelimbs
Lightweight, rigid skeleton – hollow bones
Endothermic metabolism – 104-106o F
Unique respiratory system – most efficient
Beak – no teeth
Oviparity – eggs incubated by parents
Evolution
Similarities to dinosaurs:
– Flexible, S-shaped neck
– Unique ankle joint
– Hollow bones
Birds evolved from small, fast-running
carnivorous dinosaurs
Oldest bird fossil - Archaeopteryx
Archaeopteryx
Jurassic period – 150 million years ago
Similar to modern birds because:
– Hollow bones
– Furcula: fused collarbone (aka wishbone)
– Feathers
Similar to dinosaurs because:
– Teeth
– Claws on forelimb
– Long, boney tail
Origin of flight
Two major hypotheses:
1. Ancestors were tree dwellers that ran
along branches and jumped from tree to
tree, gliding wings first evolved then the
ability to flap came later.
2. Ancestors were land dwellers that leapt
after their prey, wings served to trap or
knock down prey and over time became
large enough to fly.
Feathers
Modified scales
Two main functions:
– Provide lift for flight
– Conserve body heat
Types of feathers:
– Down feathers – insulation
– Contour feathers – streamline shape, coloration,
insulation
– Flight feathers – on wings and tail for flight
video
Parts of a feather
Structure of the feather
Follicles: tiny pits that feather develops
from
Shaft: emerges from the follicle
Vanes: 2 vanes on opposite side of shaft
Barbs: branches of the vane
Barbules: projections on the barbs with
microscopic hooks
Keratin: protein that makes up the feather
video
Care of feathers
Preening: use beak to rub feathers with oil
secreted by the preen gland at the base of
the tail.
Molting or shedding of feathers periodically
Characteristics of Birds
Section 42.2
Skeleton & Muscles
Thin, hollow bones fused together
Sternum: breastbone is attachment point
for flight muscles
Pygostyle: last fused vertebrae that supports
the tail feathers
Flight muscles account for 50% of bird’s
weight
Metabolism
Endothermic therefore require large
quantities of food to generate heat
Aquatic birds have a layer of fat to insulate
Cannot go through long periods of time
without food
Digestive & Excretory Systems
Path of food: mouth  esophagus  crop
 2-part stomach (proventriculus &
gizzard)  small intenstine with bile from
liver  large intestine  cloaca  vent
Path of wastes: blood  kidneys  ureters
 cloaca (mixes with feces)  vent
Digestive System
Respiratory System
Highly efficient
Path of air: nostrils  trachea  branched
bronchi  lungs (25%) or air sacs (75%)
Air sacs:
– 9 total
– Stores excess air
– Allows for oxygenated air in lungs during
exhale and inhale
Respiratory System
Circulatory System
Rapid heartbeat
– Up to 1000 beats per minute!
4 chambered heart
– Like mammals
Nervous System & Sense
Organs
Large brains (relative to body size)
Some birds have color vision and/or
binocular vision
Some birds have a developed sense of smell
Sense of hearing also important
Reproduction
Sperm movement: testies  vasa deferentia
 cloaca  female’s cloaca
Egg movement: ovary  oviduct 
fertilized by sperm  addition of shell 
cloaca  vent
Nest Building & Parental Care
Lay eggs in nest
Methods of rearing young:
– Precocial: active as soon as hatch
– Altricial: helpless when born
One or both parents incubate eggs by sitting
on them and covering them with their
brood patch
– Thickened, featherless patch of skin on
abdomen
Migration
Seasonal movement of birds from one
habitat to another
Cues to help navigate:
–
–
–
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Position of sun and stars
Topographical landmarks
Magnetic field
Air pressure
Ornithologist: biologist that study birds
Classification of Birds
Section 42.3
Diversity
Beak and claws infer
diet and habitat
Most widespread
terrestrial animal on
planet
23 orders of birds
Order Anseriformes
Examples: swans, geese, and ducks
Aquatic
Webbed feet
Flattened bill
Precocial young, care by female
Order Strigiformes
Examples: owls & nocturnal raptors
Sharp, curved beak
Sharp talons
Keen sense of hearing to detect prey
Order Apodiformes
Examples: hummingbirds & swifts
Small, fast-flying
Tiny feet
Long, narrow beak
Order Psittaciformes
Examples: parrots, parakeets, macaws,
cockatoos, & cockatiels
Live in the tropics
Strong, hooked beak for opening seeds
Two toes forward, two toes backward for
climbing & perching
Highly vocal
Order Picformes
Examples: woodpeckers & toucans
Nest in tree cavities
Diversity of bills based upon diet
Same feet as parrots
Order Passeriformes
Examples: familiar birds (robins, blue jays,
cardinals, etc)
perching birds: 3 toes forward, 1 toe
backward
songbirds: males produce songs to attract
mate and warn away other males
– Syrinx produces sound at base of trachea
Order Columbiformes
Examples: pigeons & doves
Plump-breasted, small heads
Short neck, legs, and beak
Crop secretes nutritious milk-like fluid to
feed young
– Crop milk
Order Ciconiiformes
Examples: herons, storks, raptors, &
penguins
World-wide distribution
– Habitat determines adaptations
Many are wading birds
Order Galliformes
Examples: turkeys, pheasants, chickens,
grouse, & quail
Fowl
Terrestrial birds
Plump-bodies with limited flying ability
Order Struthioniformes
Examples: ostriches & emus
World’s largest birds
Reduction in toe number to allow for fast
running
Bird Beaks and Feet