
The Black Bear

aka Ursus americanus
 The North American Black Bear is the best known and
most widespread of the North American bears.

The Polar Bear



aka Ursus maritimus, which means "sea bear”
Discovered 1774 by Commander C.J. Phipps
The Northern Cardinal


aka Cardinalis cardinalis
North American bird

Mammals

Two groups formed from amniotes about 300 million
years ago
 One to dinosaurs, birds, and modern reptiles
 One to synapsis and therapsids
 Gave rise to mammals and their extinct relatives
First mammals coexist with first dinosaurs during the
Triassic period for more than 150 million years
 100 million years ago, during the Cretaceous period, three
groups formed

 Monotremes – oviparous
 Marsupials – viviparous
 Placental mammals - viviparous

Birds


Evolution thought to have begun in Jurassic era from
small, fast-running carnivorous dinosaurs
Evidence show evolution from theropod dinosaurs
 First classified bird fossils were from the genus
Archaeopteryx



Begun diversifying early Cretaceous period
Survived global catastrophe that killed dinosaurs
and underwent rapid evolutionary radiation
Modern bird orders originated by 40 million years
ago

Bilaterally symmetrical


Two similar halves when divided about a single
plane
Cephalization

Development of a head – in which sense organs,
brain, and feeding organs are concentrated – in
animals

Endoskeleton
Skeleton on the inside of an animal body
 Comprised of a skull, vertebral column, pectoral and
pelvic girdles, ribs, and limb or fin elements
 Gives shape and support to the body, protects vital
organs and provides a system of rigid levers to
which muscles can attack and produce movement.
 Allows steady growth
 Present in chinoderms and other invertebrates



In birds, skeleton combines lightness with
strength
Bones are thin and hollow

Many are fused making more rigid skeleton than
reptiles or mammals
 Provides flight stability

Mammals
Incisors, canines, premolars, molars assist in feeding
process
 Food moves through esophagus to stomach
 Gastric juices kill bacteria transfers into small intestine
 Colon reabsorbs excess water and stores feces until
they’re eliminated


Birds
Don’t chew; food passes straight to esophagus
Crop, proventriculous, gizzard, small intestine to
bloodstream
 Very rapid



Birds
Wings
 Flight movements possible by large, powerful flight muscles on
breast and wings

 Account for up to 50 percent of body weight
4-chambered heart + two incompletely separate ventricles
 Double-loop circulation

 Similar to reptiles and mammals

Mammals



Forelegs and hind legs, limbs, appendages
Two atria and two ventricles
Septum completely separated ventricle
 Allows efficient oxygen transportation through the body

Birds
Lots of oxygen for high metabolism
 Air enters through nostrils on beak fills lungs while 75%
go to air sacs (usually 9) that store air

 Air sacs reduce density, aid in flight

Mammals

Lungs – contain millions of alveoli enable efficient gas
exchange
 Large surface area + small sacs for gas exchange

Two mechanisms
 Thoracic cavity – holds lungs; strenuous activity
 Diaphragm – below rib cage, enlarges thorax connects to
thoracic cavity; used when at rest

Birds
Kidneys are similar to ones in their ancestor reptiles
 Limited intake of water-filters only enough for
excretion
 Uric acid is converted nitrogen waste compound
 Uric acid can be excreted with little water


Mammals



Urea requires more water than uric acid in birds
Kidneys regulate water balance inside the mammal
Reabsorb large amounts of nephric filtrate

Birds



Two kidneys filter uric acid (nitrogenous waste)
from blood
Concentrated levels goes through ducs called ureters
to the cloaca and exit through vent
Mammals



Kidneys and accessory urinary organs
Solid waste out of large intestine
Urea and lactic acid expelled through sweating

Sexual Reproduction
 Fertilization
 Internal fertilization - sperm fuses with an egg inside
the female’s body

Amniotes – animals that produce an amniotic egg
 Amniotic – eggs with embryo that is always contained
inside water


Marsupials – offspring are born and develop in
external pouch
Some mammals develop placenta

organ w/ blood vessels that carry oxygen, nutrients
and waste to and from the embryo

Types of offspring birth


Oviparous – eggs hatch outside of the mothers
body (all birds/3 mammals)
Viviparous – no shell forms around the egg, and
the young are kept inside of the mother’s body
until they are mature enough to be born (most
mammals)

Cephalization


Neurulation


Formation of sensory organs usually towards the
anterior
Develops neural tube, gives rise to brain and spinal
cord
Center of nervous system is brain

In vertebrates spinal cord and brain are the Central
Nervous System (CNS)

Birds
Relatively large brains
 Highly developed cerebellum and cerebrum

 Cerebellum coordinates movement and flight-related
functions
 Cerebrum controls complex behavioral patterns

Large optic lobes receive and interpret visual stimuli

Mammals


Brain 15 times heavier than those of fish, amphibians
and reptiles
Large cerebrum
 Largest and most outer region of the brain
 Folded and fissured, increases surface area
 Evaluates input from sense organs
 Controls movement, initiates and regulates behavior
and functions in memory and learning

Birds

Feathers
 Insulate body to heat loss

Wings
 Modified forelimbs covered by feathers

Lightweight rigid skeleton
 Thin-walled and hollow

Endothermic metabolism
 Rapid and supplies energy for flight

Unique respiratory system
 Air sacs

Beak
 Tough, horny sheath

Oviparity
 Calcium-containing shell that encase offspring

Mammals

Endothermy
 Regulate body heat through metabolism and heat loss

Hair
 Insulation
Completely divided heart
 Milk

 Nutritious fluid produced by mammary glands on
thorax/abdomen

Single jawbone
 Lower jaw composed of single bone

Specialized teeth
 Modified for different functions






Bailey, Jill. Animal Life. New York: Oxford University Press. Inc., 1994.
Hine, Robert. "cephalization." The Facts On File Dictionary of Biology,
Fourth Edition. New York: Facts On File, Inc., 2005. Science Online. Facts
On File, Inc. http://www.fofweb.com
Hine, Robert. "endoskeleton." The Facts On File Dictionary of Biology,
Fourth Edition. New York: Facts On File, Inc., 2005. Science Online. Facts
On File, Inc. http://www.fofweb.com
Postlethwait, John, and Hopson, Janet. Modern Biolody. Austin: Holt,
Rinehart and Winston, 2006. Print.
"Reproduction of Living Organisms." Science Online. Facts On File, Inc.
http://www.fofweb.com
Zerucha, Ted. "development of the central nervous system." Human
Development, Your Body: How It Works. New York: Chelsea House
Publishing, 2003. Science Online. Facts On File, Inc.
http://www.fofweb.com