BIRDS

Evolution of birds: Fossil evidence shows that birds evolved from the same line as crocodiles and dinosaurs. Archaeopteryx was an ancient bird with a reptile-like tail, clawed fingers on the wings, teeth, a fused furculum and a body covered with feathers.

Archaeopteryx

Birds - very successful due to: - being endotherms and - being able to fly to new locations. -They inhabit a wide range of climates due to this.

Ornithology - the study of birds Evolution- evidence from: Fossils Comparative anatomy – -modern birds have structures similar to those of reptiles. -amniotic eggs -scales (feathers are modified scales and birds have scales on their feet) -crocs and birds have a 4 chambered heart -crocs and birds display maternal care

BIRD CLASSIFICATION: Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrate Class: Birds (Aves)

Over 9700 different species divided into 29 different orders. -Classified according to their morphological features including beaks, feet and plumage

General Characteristics of birds: 1. The body is covered with feathers. 2. The bones are thin and hollow. Forelimbs are wings in most species and used for flight. 4. Two hind legs support the body. 5. A tooth-less horny beak is present. 6. Birds are warm-blooded and temp. is regulated internally by their metabolism. 7. The heart is four-chambered 8. Amniotic eggs have a calcium shell and are incubated in a nest by parents in most species

CHARACTERISICS OF BIRDS: Feathers: (modified scales) Used for: Flight Insulation - Made up of keratin Four different types of feathers: Down feathers: Covers entire body of young Soft and Fluffy ~traps warm air from body On adult: Lies closest to body for insulation

Nothing as nice as a fluffy, warm down blanket on a cold winters night……..

Streamline shape of bird Bottom part similar to Down (insulation) Contour feathers: Streamline shape of bird Bottom part similar to Down (insulation) Provide coloration Camouflage Identifies species/sex Contour Feather

Flight feathers: (modified Contour) Found on wings & tail Helps provide lift for flight Flight animantion

Bristle feathers: Located on Eyes, Nostrils & Around Face Filter dirt Similar to eyelashes/nose hair

Hooks PARTS OF A FEATHER: Barbs: Many make up a vane Follicle: Tiny pit in skin where feathers develop Hooks Shaft or quill: Develops from follicle & runs up center of feather Hold barbules together Barbules: Have hooks on ends to hold barbs together Vanes: 2 vanes per feather on each side of shaft

Follicles:

Quill

VANE

Feathers are cared for by preening: Use beak to zip feathers together and waterproof them by spreading oil from the preening gland Preening Gland: Base of tail, contains oil

Molting: -Shedding of feathers -like our hair and fingernails, feathers are not living. -can not heal damaged feathers-molt immediately

Feather Lab

Skeletal and Muscular Systems: Bones are thin and lightweight hollow with honeycombed air filled spaces. A pelican is approximately 5 feet long and weighs nearly 20 pounds -However, their bones only weigh 23 ounces

Many bones are fused for greater support Example: Breast bones are fused to form the KEEL. The keel is the anchor for the powerful flight muscles.

Additional adaptations for flight: No heavy jaw bones No jaw muscles / no chewing of food No teeth Extremely thin skull bones

Muscular System: Large muscles for strength Largest muscle is the breast or pectorals muscles. -Provide powerful down stroke of the wing for flight. Skin muscles attached to each feather follicle, - -allowing feathers to alter position during flight.

Turkey breast….yum yum

Metabolism: Very fast metabolism Requires large amount of food to maintain high metabolic rate Digest food quickly ~ can’t afford extra wt of food in their system. Must eat constantly to support energy need. “You eat like a bird….” -mean you eat small amounts but actually a bird must eat a lot. Body temperature: 104-105º F

Endothermic metabolism: Generate heat to warm body internally Need large quantities of food Can’t go long periods of time w/o eating Feathers and a layer of fat help to regulate their body temperature

Feeding and digestion: Birds require a large amount of food to maintain their high metabolic rate Digestion in birds is faster than in reptiles Do not chew food Birds have a crop at base of esophagus that stores and moistens food Birds have a gizzard that contains small stones that crush food the birds swallow Baby birds lack the stones so parent regurgitates the food for the baby.

Digestive System: Passage of food: Mouth: Esophagus: Crop: stores and moistens food Two-part stomach Proventriculus -adds gastric enzymes Gizzard-contains stones for crushing food Small intestines Large Intestines (Caeca) Cloaca

Esophagus Stomach Large Intestine

-Entrance of digestive system Mouth: -Entrance of digestive system -No teeth -Uses a beak to pick up food -Beaks are specific based on what type of food is eaten. Esophagus: -Passage of food from mouth to stomach -no digestion occurs here Esophagus: Passage of food from month to stomach

Crop: Storage for food; where it’s moistened Proventriculus: First part of stomach; a gastric gland, add enzymes, where digestion starts Gizzard: Helps kneed or crust the food (eat pebbles to help crush food) Small Intestines: Where most food is digested, absorbed and broken down by enzymes and bile Large Intestines: (Caeca/um) Water absorbed, waste separated from nutrients Cloaca: Exit of digestive, reproductive and excretory systems. 45 MINUTES TO DIGEST & REMOVE!!!

Gizzard with Pebbles

Kidneys filters out the nitrogenous wastes from blood Excretory System: Kidneys filters out the nitrogenous wastes from blood Nitrogenous waste is in the form of uric acid It is less toxic It is very concentrated because it is not watered down since there is no urinary bladder. Passes out cloaca NO URINARY BLADDER= MAKES BIRD LIGHTER FOR FLIGHT

Respiratory System: Elaborate and highly efficient Needs lots of oxygen continuously for energy for flight. High metabolic rate also requires much oxygen. Therefore the lungs must have a lot of surface area for O2 and CO2 exchange

Passage of air: Pair of nostrils Trachea Bronchi Lungs Air Sacs Located near base of beak Trachea Where air passes after entering nostrils Bronchi 2 bronchi: leads to lungs and then air sacs Lungs 25% of air remains in lungs , 75% by passes lungs and goes into air sacs Air Sacs 9 air sacs, extend from lungs into bones; reduces density; lighter for flight, stores air

Esophagus TRACHEA

When a bird breathes, 75% of air enters the air sacs, 25% is inhaled and exhaled with the aide of a rib cage. Air sacs allow a large % of fresh air to remain inside of a bird at all times so they constantly have a large supply of oxygen thus a large supply of energy.

Birds receive oxygen-rich air during inhalation and exhalation in this system.

                                         Lung

Complete Septum-divides ventricles…NO MIXING of clean and dirty blood Circulatory System: 4 chambered heart, 2 loop, closed system VERY EFFICIENT 2-Atriums 2-Ventricles (THICK) A V Complete Septum-divides ventricles…NO MIXING of clean and dirty blood SEPTUM Humming Bird – beats 600 times/minute Chickadee – beats 1000 times/minute -delivers much needed food and oxygen to cells for energy.

Oxygenated blood (red) is pumped from the lungs to various parts of the body; Deoxygenated blood (blue) is returned from body to lungs.

Nervous System: Very Large Brains Coordinated movement Contains large optic lobes (very good color vision and acute hearing) No external ears-has tympanic membranes Good care of young (large cerebrum)

Olfactory lobe is small in birds -most birds sense of smell is not highly developed Example: The only predator to a skunk is an owl because owls can not smell at all.

Have nictitating membranes and bristle fibers to protect eyes The saying “You’re such a bird brain” Is a complement since they have a large cerebrum and are very good at reasoning and thinking

Reproduction: Males: Sperm is produced in 2 testes Sperm passes through small tubes called vasa deferntia into the cloaca Mating – male presses his cloaca to the female cloaca and releases sperm

Females: Single ovary on left side of body Ovary releases eggs into oviduct where they’re fertilized Fertilized eggs move down the oviduct where they receive a protective calcium carbonate covering / shell in the uterus. Egg passes out cloaca

For most birds, copulation involves a “cloacal kiss”, with the male on the female's back & twisting his tail under the female's -Copulation typically lasts just a few seconds

All birds have internal fertilization, with separate sexes. Sexual dimorphism: males are more brightly colored and have bolder feathers than females… Males also territorial.

Oviparity: Lay eggs in nest which conceals young from predators & provides shelter

Two types of hatchings: Precocial - alert and active young at hatching. Covered in down feathers when hatch. (ducklings, goslings) Altricial –incubate short time, rapid growth Can’t see and have no feathers. (cardinals, robins, eaglettes)

Precocial

Atricial

Parental Care: Both parents incubate eggs by sitting on them Have a brood patch On abdomin No feathers A lot of blood vessels to keep eggs warm

Migration: When food is scarce-fly to a new and more suitable environment.

Navigation: Use stars & sun; earths magnetic field; changes in air pressure; low frequency sounds; topographical landmarks

Pigeons: hyperlink Origins: Pigeons and doves have been around for a long time—long before humans. Rock Doves are thought to have originated in southern Asia several million years ago. Compare this to modern humans that first appeared about 120,000 years ago. Size and weight: A pigeon is about 13 inches (32 cm) in length from bill to tail and weighs a little less than a pound (0.35 kg). Males are slightly bigger than females. A pigeon family:  Hen: an adult female pigeon Cock: an adult male pigeon Hatchling: a newly hatched pigeon just a few days old Squab: a young pigeon from 1–30 days old. When ready to leave its nest, a squab can sometimes weigh more than its parents. Fledgling: a bird that is ready to fly or that has just taken its first flight Juvenile: a bird out of its nest and flying but less than eight months old