From Reptiles to Aves

Transcription

1 First Vertebrates From Reptiles to Aves Evolutions of Fish to Amphibians Evolution of Amphibians to Reptiles

2 Evolution of Reptiles to Dinosaurs to Birds Common Ancestor of Birds and Reptiles: Thecodonts Bipedal Thecodonts to Birds Caudipteryx tail feather Existed in Cretaceous Period ~124.6 million years ago Peacock-sized dinosaur Velociraptor-like Feathers on tail and arms Arms were too short to be wings. Then what is the function of feathers?

3 Archaeopteryx - An evolutionary link between reptiles and birds s/the-feathered-dinosaur/ Archaeopteryx: First known bird fossil Bird like... Contour flight feathers on wings and tail Wishbone (furcula) Archaeopteryx ancient wing First known bird fossil ~ 150 million years old Dinosaur-like... Skull has teeth Few fused bones Solid bones Long reptilian tail No enlarged breast bone Dinosaur forelimbs Fossil Record Why are many fossil records incomplete?

4 Bird Classification Domain:? Kingdom:? Phylum:? Class:? What adaptations make birds so successful? What adaptations make birds so successful? Feathers and ability to fly for most Hollowed bones 4 chambered heart Amniotic eggs Advanced system of lungs and air sacs

5 What key characteristics do all birds have in common? Similarities between birds and reptiles? 1. Vertebrates 2. Eggs 3. Oviparous (except some reptiles are viviparous) 4. Scaly lower legs and feet with claws made of. Differences between birds and reptiles? 1. Birds have 2. Birds can (most) 3. Birds are, and reptiles are ectotherms 4. Birds have 4 limbs (2 hind limbs for walking and 2 front limbs for flying) and reptile limbs vary between Birds have a 5. Birds do not have teeth they have a hard bill, and chambered heart, and most reptiles have a reptiles have teeth. chambered heart with a partial.

6 How are the bones of birds different from the bones of other vertebrates? Bird Muscles Control wings and legs Largest muscle is the muscle, it makes up 15-25% of bird s mass Connects sternum to humerus Paired with the Supracoracoideus muscle they make up - % of the bird s mass Why would birds need so much muscle in their thoracic region? Bird Skeleton Lightweight and Pneumatized Respiratory air pockets in bones Furcula little fork often called the. (formed by the fusion of two clavicles) Shock absorber for wings Stabilize thoracic skeleton

7 What are feathers used for? What are feathers used for? Feathers Reptile scales adapted into feathers Feathers are replaceable 2 types of feathers Contour Flight feathers Down Warmth Flight Warmth Mating Camouflage Intimidation Feathers Down Feathers Soft Fluffy Used for Smaller and closer to body Contour Feathers Flight feathers Provide and Strong and stiff

8 Bird Respiratory System Bird Circulatory System 4 Chamber heart, 2 loops Complete septum prevents mixing of oxygen-rich and oxygen-poor blood Air sacs allow unidirectional flow of air 2 lungs and 7-9 air sacs Air sacs form air pockets in the skeleton More efficient than mammals Bird Digestive System Pathway of food: Mouth Esophagus Crop - stores food Gizzard - grinds food Intestines Cloaca Transfer more oxygen with each breath Bird Beaks Many types of beaks Specialized for food types Other uses Grooming Moving objects Preying on food Feeding young

9 Bird Reproduction Internal fertilization Lay eggs One or both parents incubate eggs Why do birds migrate? Stimulates growth days before hatching Care for young until they can fly Why do birds migrate? For food Nesting locations

10 Navigation Sun Stars Magnetic Field Birds use wings, feathers, and physics to fly Brain contains magnetite, an iron oxide crystal that aligns with magnetic north similar to a compass needle Homing pigeons with magnets on their heads get very confused and disorientated Bernoulli s Principle Physics of Flight Bernoulli's principle states that as air moves around an object, it creates different pressures on that object. Faster air means less pressure. Slower air means more pressure. The key to flight is creating pressure upwards on the bird's wing to keep the bird in the air. This pressure produces an upward force called lift. Lift Lift is caused by the pressure under the wing being greater than the pressure above the wing. The shape and angle of the wings create the air speed/pressure difference.

11 What forces are acting on the bird? Thrust Thrust is a forward force caused by the flapping of the bird s wings. Overcomes the drag force caused by air resistance. What forces are acting on the bird? What forces are acting on the bird? Lift Lif t FA Resulting Force L Thrust Drag weight FF = drag FAT FG = weight Thru st