Birds

Ch. 12.1

• One day in 1861, in a limestone quarry in what is now Germany, Hermann von Meyer was inspecting rocks.

• He was a fossil hunter, spotted something dark in a rock.

• It was the blackened imprint of a feather!

• What he then found was Archaeopteryx which mean “ancient winged thing.”

• Paleontologists think that Archaeopteryx lived about 145 million years ago.

• It didn’t look like the birds you know, it looked more like a reptile but with wings.

Archaeopteryx

• Bird Characteristics

• Feathers• Wings• Backward toe

• Reptile Characteristics

• Long, bony tail• Teeth• Scales• Loose “fingers”

Characteristics of Birds

• Modern birds all have certain characteristics in common.

• A bird is an endothermic vertebrate that has feathers and a four-chambered heart.

• A bird also lays eggs.

Adaptations for Flight

• The bodies of most birds are adapted for flight.

• The bones are nearly hollow – makes it light weight.

• The front limbs are wings.

• Feathers help it fly.

• Birds are the only creatures today with feathers.

Feathers

• There are two kinds of feathers:– Contour feathers – is one of the large feathers

that give shape to a bird’s body.– Down feathers – are specialized to trap heat

and keep a bird warm.

Contour Feathers

• These are the feathers you think about.

• They are longer, and usually colorful.

• If you find a feather on the ground, it is usually a Contour Feather.

• It is used for flight and steering.

• They are made with “hooks, and barbs” which acts like a zipper keeping the feathers organized and neat.

Down Feathers

• These are the fluffy feathers that babies are born with.

• They are also used to make pillows and blankets if you have a “down pillow.”

• They are under the contour feathers, right near the skin of the bird.

• They are soft and flexible, unlike contour feathers.

Obtaining O2

• Flying uses a lot of energy.

• Therefore, cells must receive plenty of oxygen to release the energy contained in food.

• Birds have a system of air sacs in their bodies.

• This system connects to the lungs.

Circulatory System

• Birds have a 4 chambered heart, and two loops.

• This is very efficient and keeps the blood from mixing while circulating.

Obtaining Food

• Birds must obtain a lot of food to provide the energy it needs for flight.

• Many use their beaks which are specialized to their food.

• Some are pointy, some are spooned billed, some are curved.

Crop

• After a bird eats its food, digestion begins.

• Each organ in a bird’s digestive tract is adapted to process food.

• Many birds have an internal storage tank, or crop.

• This connects to the stomach.

Gizzard

• The stomach has 2 parts. The first is where food is bathed in chemicals that begin to break it down.

• Then it moves to the thick-walled, muscular part of the stomach called the Gizzard.

• It squeezes and grinds the partially digested food.

• Birds do not have teeth, so they swallow small stones to help grind their food.

Homeostasis

• Because birds are endotherms, they also need a lot of energy to keep warm.

• Each day, an average bird eats food equal to about a quarter of its body weight.

• To keep warm, they also use their down feathers.

Reproduction and Caring for Young

• Like reptiles, birds have internal fertilization and lay eggs.

• Bird eggs are similar to reptile eggs except that their shells are harder.

• In most birds, the female lay the eggs in a nest that has been prepared by one or both parents.

• For a bird egg to hatch, it must be kept the same temperature as the parent.

• This is why it sits on its eggs.

• Chicks take about 12 to 80 days to develop.

• When it is ready to hatch, a chick pecks its way out of the eggshell.

• Some chicks are born with a layer of down feathers

Birds in the Environment

• Birds are adapted for living in diverse environments.

• You can see some of these adaptations in the shapes of their legs, claws, and bills.

• They play an important role in the environment by pollinating flowers and spreading seeds (pooping).