Chapter 4

Section 1 and 2

Introduction

1861: Hermann von Meyer found a fossil imprint

of a feather

A month later he found a skeleton surrounded by a clear imprint of the feathers

Introduction

Introduction

Introduction

Archaeopteryx Lived about 145 million years ago Looked like a reptile with wings

Mouthful of teeth – modern birds don’t Long, bony tail – modern bones don’t Feathers – reptiles don’t

Descended from some kind of reptile possibly a dinosaur

What is a Bird?

Characteristics: Endothermic Vertebrate Has feathers 4-chambered heart Lays eggs

What is a Bird?

Have scales on their feet and legs

Most birds fly

Have wings made of nearly hollow bones

Feathers

What did feathers evolve from? Reptile’s scales

Both are made of the same tough material as our fingernails

Feathers

What are the 2 types of feathers? Contour

Down

Contour Feathers

Large feathers that give shape to a bird’s body

The feathers that extend beyond the body on the wings and tail are flight feathers Balance and steering

Contour Feathers

Parts of a Contour Feather

Central shaft Hair-like projections called barbs

Arranged parallel to each other Pulling apart the barbs unzips the

surface of a flat wing Preening:

Pull the barbs back together to smooth the feather

Down Feathers

Short, fluffy feathers that are used to trap heat and keep the bird warm

Found right next to the skin – base of the contour feathers

Soft and flexible

Down Feathers

Insulator: Material that does not

conduct heat well and traps prevent it from escaping

Air is the insulator for birds

Trap a blanket of warm air next to their skin

Food and Body Temperature

How do birds capture food? Bills

The shape helps them feed quickly and efficiently

Food and Body Temperature

Hawk Curved bill Acts like a meat

hook Holds prey with

claws and rips the flesh off with its bills

Food and Body Temperature

Woodpecker Straight, sharp bill

Chips into wood

Spears insects with its long, barbed tongue

Food and Body Temperature

Digestion Crop: Storage tank for food before

swallowing Stomach: Chemicals added to start to

break food down Gizzard: Partially digested food is ground

up Stones help to grind food by rubbing against

the food and crushing it

Food and Body Temperature

Food and Body Temperature

Endothermic – maintain their own body temperature They need a lot of energy to maintain

their body temperature A lot of energy is used in flight They eat about a quarter of their body

weight in food every day!

Oxygen

They need oxygen to release the energy in food

How do birds get oxygen? Air sacs which connect to lungs

Enable birds to extract much more oxygen from each breath of air than other animals

Oxygen

Circulation

Circulation

Chambers of the heart: 2 Atria 2 ventricles

Right side pumps blood to the lungs where it picks up oxygen

Oxygen-rich blood returns to the heart on the left side

Pumps out to the body to deliver oxygen

Circulation

Advantage of a 4-chambered heart No mixing of oxygen-poor and oxygen-

rich blood

Blood arriving to tissues has plenty of oxygen

Nervous System and Senses

Do birds have quick or slow reactions? Quick – to be able to land safely and

avoid crashing into branches and trees

Well-developed brain and finely-tuned senses of sight and hearing Well-developed brain for flying, singing, and

finding food

Reproduction

Internal or external? Internal – lay

eggs Harder shells

then a reptile

Reproduction

What do eggs need to develop? Need the warm from a parent to develop Parents incubate the eggs by sitting on

them In some species 1 bird does the

incubating In other species they alternate incubating

Reproduction

Length of incubation There is no set length Sparrows take 12 days Chicks take 21 days Albatross eggs take 80 days

The bigger the bird the longer the incubation

Reproduction and Care

How does a bird hatch? Pecks its way out of the egg Some are featherless, blind, and weak Others are covered with down and can

run right away

Parents provide protection and food until the baby can fly

Diversity

Most diverse land-dwelling vertebrates

10,000 species

Adaptations Long legs Toes adapted to perch Bills used to filter food from water

Importance

What do birds provide? Food Feathers – stuff pillows and clothing Carry pollen for flowers Carry seeds Eat pest animals