Lecture 10: Mammals (pp.757-759)
Mammal evolution
Mammals
The bottom of the ocean is a nearly
constant temperature. Hence, sea
cucumbers living at the bottom of
the ocean are BEST characterized
as:
a. 
b. 
c. 
d. 
ectothermic homeotherms
ectothermic poikilotherms
endothermic homeotherms
endothermic poikilotherms
Which of the following is NOT an
amniote?
a. 
b. 
c. 
d. 
e. 
Turtle
Lizard
Cat
Bluejay
Frog
Figure 34-34
Reptiles
Turtles
Lizards,
Snakes
Crocodiles
Birds
LDC=lactose digestion capacity
LDC = lactose digestion
Capacity, so low LDC ~ lactose
intolerant
-lactose intolerance is a genetically determined trait
-It has simple Mendelian genetics (tolerance is dominant, intolerance is
recessive).
-Lactose intolerance is the ancestral condition in humans
-Lactose tolerance evolved twice in humans, why?
Mammals can be divided into three large groups:
1) The monotremes (lay eggs, found only in
Australia and New Guinea).
2) The marsupials (or Metatheria)
3) The Eutherians
(or placentals)
Monotremes inlclude the echidnas and platypus
Short and long-beaked echidna
Platypus
Monotremes are oviparous
(they lay a leathery egg).
Platypus possess a spur connected to a
venom gland and a rubbery bill with
thousands of touchsensitive and
electro-sensitive receptors.
Choose the INCORRECT association:
a. 
b. 
c. 
d. 
e. 
amphibians – tetrapods
reptiles – amniotes
lancelets – chordates
lampreys - jawed vertebrates
birds- bony vertebrates
Some freshwater snails are
brooders; they give live birth to
offspring that are nourished inside
a brood sac with yolk. These snails
are best described as:
a.  Viviparous
b.  Aviparous
c.  Oviparous
d.  Vivoviparous
e.  Ovoviviparous
Marsupials (≈270 species)
bandicoot
water opposum
Feathertail glider
virginia Opposum
wombat
≈70 species
≈200 species
honey possum
gray kangaroos
koala
Tasmaniand devil
Sugar glider
Marsupial young are tiny at birth.
Greater bilby
(Macrotis lagotis)
The Eutherians (placentals)
complete their
embryonic
development within
the uterus and are
joined to their
mothers by the
placenta
The Eutherians are diverse
Whales are embedded within the even-toed
ungulates. This makes the Artiodactyla?
a. Aphyletic
Recent fossil evidence shows
b. Monophyletic
that the ancestors of whales
c. Paraphyletic
were aquatic deer!
d. Polyphyletic
Whales are embedded within the even-toed
ungulates. This makes the Artiodactyla?
Paraphyletic! (unless you want to refer to
Whales as ungulates!)
Recent fossil evidence shows
that the ancestors of whales
were aquatic deer!
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Primates
Family: Hominidae*
Homo sapiens
You will spend an
inordinate amount of time
studying this organism….
Fig. 34.38