What to study for quiz on Wednesday

Focus on the following life processes of birds:

• Respiration
• Digestion
• Ability to fly

Also feathers and limbs

Bird Family Life

• For birds, the process of reproduction and raising young is quite complicated, usually involving courtship and nest construction.
• Courtship is the male bird attempting to attract a mate.
• Males are more colorful than females.

• Birds are oviparous, producing amniotic eggs.
• Male transfers his sperm into the cloaca of the female (internal fertilization).
• Females have a single ovary for ova production.
• Fertilization occurs within the oviduct.

• Embryo appears as a small nucleus in the yolk.
• Yolk is coated with protein-containing substance called albumen (the white part of the egg). 
• Encased in a shell.
• The shell may range in color from white to almost black, and it may have markings like spots, splotches, or streaks. While a bee hummingbird egg is the size of a pea, an ostrich egg may weigh 1.5 kg (3.3 lb) and could hold 4700 of the small hummingbird eggs.

• Eggs and young birds require parental care.
• The egg require incubation. Usually one or both parents do it.
• There are two types of chicks after they hatch:
• Altrical chicks
• Precocial chicks
• Altrical chicks
• Hatch in less than two weeks and emerge naked, blind and helpless.
• All they can do is open their mouths and eat.
• Parents produce less than 6 eggs at a time.

• Precocial chicks
• Longer incubation period, sometimes as long as a month.
• When hatched, they are well developed, alert and able to move.
• Covered with soft down.
• Stay close to parents for protection.

• Most birds have a reproduction cycle of one year, each year with a different mate. 
• Some birds mate for life.
• Eagles and penguins.

Migration

• The ideal place for raising offspring may not provide suitable year-round conditions. Some birds overcome this dilemma by migrating.
• Almost 1/2 of all bird species in the Norther Hemisphere travel south in the winter and north in the summer. 
• Seasonal, predictable, and repeatable on an annual basis.
• Why migrate?
• They can live all year in warm climates where there is lots of food.
• Best environment for raising young.
• The time, route, destination, and other aspects of bird migration are inborn.
• Mechanism for navigation not completely understood.
• Might use landmarks, but some fly over open water.
• Birds have an instinctive sense of direction.
• Some detect magnetic poles
• Some use stars and sun
• The arctic tern covers the greatest distance.
• 17,700 km from the Arctic Circle to Antarctica.

Bird Systems

Birds must accomplish the same internal processes as all other vertebrates— digesting and absorbing food, bringing oxygen and nutrients to the cells, eliminating carbon dioxide and other wastes, and responding to their environment. The challenge is accommodating these diverse tasks in a lightweight flying package. Each of the familiar life processes discussed in this section is uniquely modified by the Creator to serve a bird’s high-energy lifestyle.

Digestion in Birds

• High body temperature and flying means they have an enormous energy demand.
• So they eat large quantities of food.
• Some adult birds can eat a quarter of their weight in a day
• Once ingested, the food is quickly digested.
• This is essential because birds cannot afford to carry heavy quantities of food in their stomachs.
• Uses its unique beak for gathering food.
• Appearance and use vary with the bird’s diet. 





• Food is usually swallowed whole, passes through the esophagus and enters the crop.
• Crop is a holding area for the food.
• From the crop, it passes into the first part of the stomach (proventriculus)  where digestion juices are produced.
• The gizzard is the second part. Here the food is ground down by sand and stones that the bird swallows. 
• The food then passes into the intestine, where final digestion and absorption occurs.
• Undigested wastes are passed into the cloaca and then out of the body. 
• The cloaca is a common opening for the intestines, kidney ducts, and reproductive organs.

Respiration

• Their lungs are unable to provide enough oxygen.
• A series of air sacs aids the lungs.
• 25% of the air is draw in the lungs & 75% to the air sacs.
• As the bird exhales, the air in the lungs passes out, and the fresh air from the air sacs passes through the lungs.
• Fresh air passes through the lungs during inhaling and exhaling. 
• Respiration also helps them remain cool. 
• They sweat a little, but not enough. 
• They pant like dogs.
• Also used for vocalization.
• They have a syrinx (song box). 
• They perfect the call by imitating others from their species. 

Circulation and Excretion

• 4 chambered heart
• What does this mean? 
• Complete separation of oxygenated and deoxygenated blood.
• Right side of heart receives the blood and pumps it to the lungs.
• Lungs oxygenates the blood which then goes to the left side of the heart. 
• From there it is pumped to the body. 
• To maintain their high metabolism, the heart beats rapidly. Average of 135-570 bpm. Some species can reach 1000 bmp.
• Birds generally don’t die of old age, but “burn themselves out.”
• They have high blood pressure and can die of heart failure in times of stress.
• Metabolic wastes are filtered from the blood by a pair of kidneys. 
• Waste empties directly into the cloaca. 
• No bladder. Makes them lighter for flight.

Response

God’s design becomes more obvious from a study of the various animals. Reptiles, amphibians, and fish rely heavily on the senses of smell and taste. In contrast, their vision and hearing are weak. Many of these animals live in a watery environment that muffles sound and reduces light, making hearing and vision of little value. Even those reptiles and amphibians living on land have little use for strong eyes; they live in or close to the ground, limiting their field of vision. God provided the specific senses these animals need for their activities and environment.

• Birds have large, generally immovable eyes. Birds must move their neck to look around. 
• Some birds have better eye sight than us. 
• A hawk can spot a rabbit  from 1.5 km away. 
• Owls can spot prey in 1/10 to 1/100 of the brightness needed for man to see.
• Birds have ear canals covered by feathers.
• They have sensitive hearing in the upper sound range.
• The brain of the bird is larger than all other vertebrates except mammals.
• Olfactory lobes are small, smell is not important (except for birds that feed on dead animals.
• The cerebrum, responsible for instinct, is also large.
• Optic lobes are large.
• Cerebellum, coordinates the muscular activities, is large.

Class Aves: The Birds - Characteristics

Flight

• More than 9000 species can fly
• Those who are too heavy to fly, often “fly” underwater
• All birds have feathers, protein based structures that provide covering, insulation, and shape
• Front limbs covered with feathers - wings
• More than just wings:
• Birds bones are hollow, to reduce their weight

• Requires enormous amount of energy and lots of oxygen.
• Just two lungs, but they are connected to many sacs to multiply the volume.
• High metabolism allows them to access energy quickly
• Keeps their internal temperature at 41 degrees C (106 degrees F)
• No teeth, just a beak that makes them lighter
• All oviparous, they don’t have to carry them in their body

Feathers of Birds

• Make the birds aerodynamic
• Retains heat
• Cushion during collisions
• Camouflage & identifying a mate
• Common types of feathers:
• Down feathers: provide insulation as well as a cushion
• Contour feathers: cover the body and give it shape and color
• Flight feathers: extend from the wings and tail

Because feathers are dead, they must molt.

It is a very orderly process to make sure that they can still fly.

Feathers molt one pair at a time. No more feathers are lost until the molted pair are replaced.

Appendages of Birds

• Wings for flying (unless you are a penguin or ostrich)
• Not used to manipulate things
• Long flexible necks are substitutes for arms and hands
• Legs are thin and covered with scales with three or four clawed toes.
• Depends on the type of bird and their function

Skeleton of Birds 

• Unusual features of the birds skeleton:
• Upper jaw and lower jaw are elongated and form a beak.
• Many neck vertebrae grant free movement of the head.
• The vertebrae of the tail are free moving and help to guide it in flight
• The trunk vertebrae, the flat ribs, and the sternum are fused to make the trunk a rigid framework
• The large sternum has a central ridge called a keel. It provides attachment for flight muscles
• The clavicles are enlarged and fused, forming the “wishbone.” This also provides attachment for flight muscles.

Study Guide for Quiz Monday April 7th

• Characteristics of Phylum Chordata:
• Dorsal notochord
• Dorsal tubular nerve chord
• Pharyngeal pouches

Vertebrate Classification

• Ectothermic
• Endothermic

Vertebrate Support

• Axial skeleton
• Appendicular skeleton
• Pectoral and pelvic girdle

Vertebrate Circulation

• Blood vessels
• Hemoglobin

Nutrition

• Herbivores
• Carnivores
• Omnivores 

Vertebrate Reproduction

• Types of fertilization
• Methods of development
• Oviparous
• Viviparous
• Ovoviviparous

Behavior

• Inborn
• Conditioned
• Intelligent

Nervous System

• Five lobes of brain