Transcript Reptiles and Birds

Reptiles and Birds
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
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
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
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
Reptile Circulatory System
Reptile Response

The basic pattern of a reptile’s 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
Reptile Reproduction



All reptiles reproduce by internal
fertilization
Most reptiles are oviparous (lay eggs
that develop outside the mother’s 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
Structure of an Amniotic Egg
Types of Reptiles
Lizards
Komodo Dragon
Chameleon
Geckos
Horned Lizard
Frilled Lizard
Gila Monster
Snake Anatomy
Turtles & Tortoises
Alligators & Crocodiles
The Tuatara
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
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
Feathers

Origin:




Originally thought to have evolved from
scales
Now thought to be novel structures
Composed of beta-keratins
Weigh 2-3 times the skeleton
http://www.themodernapprentice.com/feathers.htm
A group of crows is known as a murder.
Functions of Feathers





Protection
Insulation
Flight
Visual Communication
Modified for more
Feather Structure
Feathers




Down feathers - provide insulation
Contour feathers - cover head and
body, provide coloration
Flight feathers - on wings and tail,
provide lift
Feathers are covered in oil to keep
them water proof - "like water off a
duck's back" - this oil is secreted from
a preen gland
Feather Types
• Contour and
Flight
• Down (plumules)
• Semiplumes
• Filoplumes
• Bristles
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
Form, Function, and Flight
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 bird’s feathers insulate its body enough
to conserve most of its metabolic energy
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 bird’s beak, or bill, is adapted to the
type of food they eat
Bird Digestion
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
Birds have more efficient lungs
Inhalation – all the air sacs fill
- read air sacs fill with fresh air from atmosphere
- front air sacs fill with depleted air which has pass through the lungs
Exhalation expels air from air sacs
- air from rear air sacs passes through the lungs into front air sacs
- air from front air sacs is expelled to the atmosphere
-- Two cycles required for air to pass through whole system
-- Countercurrent exchange system increases efficiency
Circulation, Excretion, and
Response in Birds

Circulation


Excretion


4 chambered hearts and two separate
circulatory loops
Similar to those of reptiles – white, pasty uric
acid droppings
Response



Well developed sense organs
Well developed eyes that can see color
Excellent hearing
Reproduction in Birds

Bird eggs are amniotic eggs


They have hard outer shells
Most birds incubate their eggs until they hatch
Structure of an Amniotic Egg
Classification

Based on feet and beaks

Order Passeriformes - songbirds (bluebirds, robins,
sparrow)

Order Falconiformes - birds of prey (hawk, falcon,
eagle)

Order Anseriformes - swimming birds (duck, goose,
swan)

Order Galliformes - fowl (pheasant, turkey)

Order Ciconiformes - wading birds (heron, flamingo)
Bird of Prey
Classification
Wading Bird
Songbird
Swimming Bird