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 O 2 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).