Birds

Zoology

Class Aves

• Wings• Feathers• No teeth• Flexible long neck• Scales on legs• Bones with air spaces• Endothermic• Four chambered heart• Multiple air sacs for

respiration

WHAT BODY PARTS DOES A BIRD HAVE TO HELP IT FLY?

EVERYTHING!

EVERY body system in a bird is modified in some way to help it fly!

MODIFICATIONS ofSKELETAL SYSTEM

Bones = hollow/air sacs extend into bones to make them LESS DENSE = fused to make them STURDY

FURCULA – stabilizes shoulders during flight

STERNUM- attaches flight muscles

PYGOSTYLE- support for tail

Adaptations for Flight

• Honey combed bones– Air cavities– Less weight– Internal “struts” for

strength

SKELETALHollow bones = light

weight

Image from: BIODIDAC

Light Weight Skeleton

• Frigate bird• 7 foot wing span• 4 ounce skeleton

Adaptations for Flight

• Enlarged sternum– Flight muscle

attachment

• Long neck– balance

Image modified from:http://www.biology.eku.edu/RITCHISO/554notes1.html

FURCULA – “wishbone” or fused clavicles to provide sturdier, stronger skeleton for flightPYGOSTYLE – fused vertebrae to provide balance during flightSTERNUM—large sternum to support chest muscles used for flight

FUSED BONES = Sturdy

Skull

• Most bones fused• Much lighter than

reptile or mammal skull

MODIFICATIONS ofMUSCULAR SYSTEM

HUGE PECTORALIS MUSCLE

provides power to move wings

PECTORALIS & SUPRACORACOIDEUS make up 35% of total body weight

MUSCULAR SYSTEM

Adaptations for Flight

• Wing– lift

MODIFICATIONS ofINTEGUMENTARY SYSTEM

• Feathers- (light weight & sturdy)

provide lift & protect against heat loss

• Preen gland keeps feathers “fly-able”• Streamline body to decrease air/wind

resistance

Adaptations for Flight

• Feathers– Light weight– Strong– Increased surface

area

Adaptations for Flight

• Reduce body weight– No teeth– No urinary bladder– No penis– Only one ovary

Image from: http://www2.thny.bbc.co.uk/education/darwin/exfiles/archaeopteryx.htm

ARCHAEOPTERYX First bird Fossil image from:

http://www.ucmp.berkeley.edu/diapsids/birds/archaeopteryx.html

Archeopteryx

• Reptile characteristics– Teeth– Boney tail– Fingers with claws

• Bird characteristics– Feathers– Furcula

Evolution of FlightRunning Hypothesis

Evolution of FlightGliding Hypothesis

MODIFICATIONS ofCIRCULATORY SYSTEM

Heart large for body size-pumps more blood

Closed 2 loop system- most efficient/faster

Complete septum/4 chamber heart- keeps Low/High oxygen blood totally separated

Rapid heart rate- delivers more oxygen/faster

HEART

Heart = 1 ½ to 2 times larger than in equal size mammal

Heart rate much faster to move more blood

HOW FAST IS THAT?A human heart beats ~ 60-90 times/min

A resting hummingbird’s heart beats 250 times/min. Or 1200 beats per minute (BPM) when feeding.

http://www.deskpicture.com/DPs/Nature/Animals/hummingbird.jpg

HEART

COMPLETE SEPTUM NOW4 chambers 2 atria/2 ventricles

Image by Riedell/VanderWal©2005

SINUS VENOSUS & CONUS ARTERIOSUS ARE GONE

• Main vein returning to heart = VENA CAVA

• Main artery to body = AORTA• Main artery to lungs = PULMONARY

http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_anatomy.html

1 loop 2 loops 2 loops2 chambers 3 chambers 4 chambersFish amphibians birds &

& reptiles mammals

4 CHAMBER HEART2 LOOPS

MODIFICATIONS ofENDOCRINE SYSTEM

ENDOTHERMIC METABOLISM-

provides maximum energy for extended activity (flying)

BURNING more GLUCOSE faster… is where the heat comes from!

Image from:http://www.rit.edu/~vertzo/Pigeon/PigeonPages/Home.html

Oil makes feathers waterproofPreening straightens feathers and re-hooks barbules

PREEN GLAND

… to eat like a bird

means to eat very little

BUT… Birds EAT A LOT

http://www.harrybliss.com/store/images/eat_like_a_bird.jpg

Most birds eat half their weight in food every day. That's like a 100-pound person eating 50 pounds of food in a day. And some young birds eat more than their weight in food every day!

MODIFICATIONS ofDIGESTIVE SYSTEM

• Fast efficient digestive system fuels endothermic metabolism for more energy for extended activity

• CROP- stores next batch so food always moving through

• 2 part stomach (Crop/Gizzard)- so food moves through faster

• COLIC CAECA- help break down plants

• LONG SMALL INTESTINE-absorbs lots of nutrients

• SHORT LARGE INTESTINE- Absorbs less water / feces not stored… out of body as it is made so weigh less

Digestive System

• Crop– Storage

• Proventriculus– Enzymes

• Gizzard– Grind food

• Cloaca– Waste– Reproduction

CROP

No digestion happens hereStores and moistens food waiting to be digestedAllows food to move faster/next batch is waiting

Image by Riedell/VanderWal©2005

CROP MILK

COLUMBIFORMES- crop makes nutritious fluid called CROP MILK for babies

http://www.joanbramsch.com/images/feeding.jpg

GIZZARDMuscular

Contains gravel/rocks

to grind food

SMALL INTESTINE (Duodenum & Ileum)

LARGE INTESTINE

isn’t very large!

Absorbs less water back from feces

(Water is HEAVY!)

EXITS through CLOACA

COLIC CAECAPouches on

intestine

Contain bacteria to digest plants

MODIFICATIONS ofRESPIRATORY SYSTEM

• SUPER EFFICIENT RESPIRATORY SYSTEM gets the most oxygen possible

• Extra AIR SACS (posterior and anterior) allow oxygen in lungs on both the INHALE AND EXHALE

• Air sacs extending into bones makes skeleton less dense

• Alveoli increase surface area for more gas

exchange

TRACHEA BRONCHI

Cartilage rings keep airway open

Image by Riedell/VanderWal©2005

SYRINX

VOICE BOX

Image by Riedell/VanderWal©2005

LUNGS

Remove 31% of oxygen ; Human lungs remove 24%

Respiratory System

• Seven to Nine air sacs– Connect to lungs and

centers of bones– Cools the bird

• Fresh air always moving– No dead ends as in

mammals

• Each wing beat moves air– Never run out of air

AIR SACSSTORE AIR No gas exchange

ALLOW OXYGEN IN LUNGS on the

INHALE and on the EXHALE

Air Circulation

• An inhale will move oxygen / air in through the trachea and some air will move to the posterior air sacs while air that was in lungs moves to the anterior air sacs

• On the exhale, the air that was in anterior air sacs moves back out of body while the air in posterior air sacs move to the lungs

• This is a constant and continuous flow of air through respiratory system, not an “in, then out” system like ours

Multiple air sacs

Air sacs increase buoyancy and all one way oxygen flow for more efficient gas exchange

OXYGEN on the EXHALE

Animation from: http://www.sk.lung.ca/content.cfm/birds

MODIFICATIONS ofEXCRETORY SYSTEM

Excrete nitrogen waste as URIC ACID- so uses less water to dilute

No URINARY BLADDER- so urine (water) not stored… less weight

KIDNEYS & URETERS

MODIFICATIONS ofREPRODUCTIVE

SYSTEM• Female has only ONE OVARY & OVIDUCT

on left side … less weight

• OVIPARITY- lay eggs OUTSIDE of body … less weight

• REPRODUCTIVE ORGANS-enlarge during breeding season/shrink rest of time

TESTES

TESTES

KIDNEYS

URETERS

CLOACA

OVARY make eggs

OVIDUCTS add albumen/shell

INTERNAL FERTILIZATION

http://people.eku.edu/ritchisong/avianreproduction.html

http://www.usgs.nau.edu/swwf/images/WIFL%20nest%20with%20eggs%20-%20MD.jpg

OVIPAROUSLay amniotic eggs

DIRECT DEVELOPMENT2 KINDS OF BABIES

ALTRICIAL = HELPLESS

hatch without feathers, eyes closed, can’t walk, parents must feed every 20 min

Ex: songbirds,

pigeons, raptors

http://www.kathyskritters.com/tales/robins/images/baby_robins_5-13.jpg

DIRECT DEVELOPMENT 2 KINDS OF BABIES

PRECOCIAL – MORE INDEPENDENT

hatch with fuzzy down, can follow parent and feed itself soon after hatching

EX: Ducks and geese

http://cowpi.com/journal/2004/06/the_dangers_of_leadership.html

Chicks

• Altricial– No feathers– Cannot walk or see– Cannot feed

themselves

Precocial– Down feathers– Can walk and see– Can feed themselves

Sexual Selection

MODIFICATIONS ofNERVOUS SYSTEM

• Large brain for body size = “smarter”• Bigger CEREBRUM for more complex

behaviors problem solving; learning; navigation;

• Bigger CEREBELLUM- for muscle coordination• Bigger OPTIC LOBES for better vision; 3D & Color• Concentration of iron in brain to act as compass

http://www.wtamu.edu/~rmatlack/pigeon_dissection/brain.jpg

EYESBIG for size of head See in COLOR

Eyes on front of face- gives depth perception Seen in predators

Eyes on sides of head-Gives wide range of vision Seen in prey

Kestral Image from:http://www.biology.eku.edu/RITCHISO/birdbrain2.html

Vision

• Up to 8 times keener than human vision

• Each eye moves indendtantly

Bird Classification

• 28 orders• 9600 species

Order Struthioniformes

• Large flightless bird• Two toes

Order Pelecaniformes

• Gular sac

Order Ciconiiformes

• Long legs for wading• Long necks

Order Anseriformes

• Flat bill• Webbed feet

Order Falconiformes

• Hooked bill• Talons• Eagle• Hawk• Falcon

Fastest Animal

• Peregrine falcon• Strikes prey at 180

mph

Order Passeriformes

• Perching foot• Songbirds• 5000 species• Mocking bird• Thrushes• Swallows• Magpie • Crow• Starling• Jays

Order Columbiformes

• Short neck• Short legs• Pigeons• Doves

Order Strigiformes

• Large eyes• Silent flight• Nocturnal predator• Owls

Order Apodiformes

• Small bird• Rapid wingbeat• Hummingbirds

Hummingbirds

• Fly up, down, left, right, backwards and upside down

• Wings beat 50 -200 times per second

• Heart rate =600 bpm• Eat 2/3 body weight

each day• Nectar, pollen &

insects

Order Galliformes

• Chicken like• Strong beaks• Heavy feet• Chicken• Turkey• Pheasants• Quail

Order Charadriiformes

• Short bill• Strong fliers• Shorebirds• Gulls

Order Psittaciformes

• Thick tongue• Hinged and movable

upper beak• Bright colors• Parrots• Parakeets

Order Piciformes

• Two toes forward and two toes backward

• woodpeckers

Order Sphenisciformes

• Webbed feet• Wings as used for

swimming• penquins

Beak Adaptations

• Ripping flesh

Beak Adaptations

• Eating seeds

Beak Adaptations

• Sucking nectar from flowers

Beak Adaptations

• Catching fish

Beak Adaptations

• Basket-like bill to hold fish caught under water

Beak Adaptations

• Filtering

Migration

• Migration to find food and reproduce

• Sissor-tailed flycatchar

• Migates to Central and South America in October

• Returns in April

Migration

• Arctic tern• Migrates 25,000

miles!

The End

References

• Content and slides taken from:

• Professor Dennis Anderson at Oklahoma City Community College

• Kelly Riedell and her zoology website

• Prentice Hall Biology 2002

• McGraw Hill Zoology 2008