Reptiles and Birds

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Reptiles and Birds

• Unit VI
• Chapter 31

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Reptiles

• A reptile is a vertebrate that has dry, scaly
  skin, lungs, and terrestrial eggs with several
  membranes

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Form and Function in Reptiles

• Most reptiles have adapted to a fully terrestrial
  life
• tough, scaly skin
• well developed lungs
• a double-loop circulatory system
• a water-conserving excretory system
• strong limbs
• internal fertilization
• shelled, terrestrial eggs
• control of body temperature by changing their
  environment

4
Body Temperature Control in Reptiles

• Reptiles are ectotherms
• They rely on behavior to help control body
  temperature
• To warm up, they bask in the sun
• To cool down, they move to the shade

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Reptile Feeding Respiration

• Reptiles range from herbivores to carnivores
• The lungs of reptiles are spongy, providing more
  gas exchange area than those of amphibians
• Most reptiles have 2 efficient lungs to exchange
  gas with the environment

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Reptile Circulation Excretion

• Reptiles have an efficient double-loop
  circulatory system
• Their heart contains two atria and either one or
  two ventricles
• Urine is produced in the kidneys of reptiles
• By eliminating wastes that contain little water,
  a reptile can conserve water

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Reptile Circulatory System
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Reptile Response

• The basic pattern of a reptiles brain is similar
  to that of an amphibian
• In addition to a pair of nostrils, most reptiles
  have a pair of sensory organs in the roof of the
  mouth that can detect chemicals
• Reptiles have simple ears and can pick up on
  ground vibrations and body heat

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Reptile Reproduction

• All reptiles reproduce by internal fertilization
• Most reptiles are oviparous (lay eggs that
  develop outside the mothers body)
• Reptilian eggs are amniotic
• They contain a shell and membranes that create a
  protected environment in which the embryo can
  develop without drying out

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Structure of an Amniotic Egg
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Groups of Reptiles

• Lizards and snakes
• Order Squamata scaly reptiles
• Crocodilians
• Order Crocolilia
• Turtles and tortoises
• Order Chelonia
• Tuatara
• Order Rhynchocephalia beak-headed reptiles

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Birds

• Birds are reptile-like animals that maintain a
  constant internal body temperature
• They have an outer covering of feathers two legs
  that are covered with scales and front limbs
  modified into wings

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Birds

• This single most important characteristic that
  separates birds from living reptiles, and from
  all other living animals, is feathers
• Feathers are made mostly of protein and develop
  from pits in the birds skin
• Feathers help birds fly and also help to keep
  them warm
• The 2 main types of feathers are contour feathers
  and down feathers

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Form, Function, and Flight

• Birds have a number of adaptations that enable
  them to fly
• Highly efficient digestive, respiratory, and
  circulatory systems
• Aerodynamic feathers and wings
• Strong chest muscles

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Form, Function, and Flight
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Body Temperature and Control in Birds

• Birds are endotherms (animals that can generate
  their own body heat)
• They have a high rate of metabolism compared to
  ectotherms (metabolism produces heat)
• A birds feathers insulate its body enough to
  conserve most of its metabolic energy

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Bird Feeding

• The more food a bird eats, the more heat energy
  its metabolism can generate
• For this reason, the phrase eats like a bird is
  quite misleading birds are voracious eaters
• A birds beak, or bill, is adapted to the type of
  food they eat

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Bird Digestion
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Bird Respiration

• When a bird inhales, most air first enters large
  posterior air sacs in the body cavity and bones
• The inhaled air then flows through the lungs in a
  series of small tubes
• A complex system of air sacs and breathing tubes
  ensures that air flows into the air sacs and out
  through the lungs in a single direction
• This constant, one way flow of oxygen-rich air
  helps birds maintain their high metabolic rate
  and generates enough energy for flight

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Circulation, Excretion, and Response in Birds

• Circulation
• 4 chambered hearts and two separate circulatory
  loops
• Excretion
• Similar to those of reptiles white, pasty uric
  acid droppings
• Response
• Well developed sense organs
• Well developed eyes that can see color
• Excellent hearing

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Reproduction in Birds

• Bird eggs are amniotic eggs
• They have hard outer shells
• Most birds incubate their eggs until they hatch