Transcript 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:
1.
Fossils
2. 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.
3. 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)
1. Used for:
Flight
 Insulation
- Made up of keratin
Four different types of feathers:
1. 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……..
2. Contour feathers:
 Streamline shape of bird
 Bottom part similar to Down
(insulation)
 Provide coloration
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Camouflage
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Identifies species/sex
Contour Feather
3. Flight feathers: (modified Contour)
 Found on wings & tail
 Helps provide lift for flight
Flight animantion
4. Bristle feathers:
 Located on Eyes, Nostrils & Around Face
 Filter dirt
 Similar to eyelashes/nose hair
PARTS OF A FEATHER:
Follicle: Tiny pit
in skin where
feathers develop
Shaft or quill:
Develops from
follicle & runs up
center of feather
Vanes: 2 vanes
per feather on
each side of
shaft
Barbs: Many
make up a
vane
Hooks
Hold barbules
together
Barbules: Have
hooks on ends
to hold barbs
together
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:
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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.
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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
Small intestines
Proventriculus
-adds gastric enzymes
Gizzard-contains
stones for crushing
food
Large Intestines (Caeca)
Cloaca
Esophagus
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Large Intestine
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
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
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
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.
Circulatory System:
 4 chambered heart, 2
loop, closed system
VERY EFFICIENT
A
2-Atriums
2-Ventricles (THICK)
V
 Complete Septumdivides ventricles…NO
MIXING of clean and
dirty blood
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:
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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