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

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

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

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