BIOLOGY 110
Lecture 4 (Sept. 20 2013)
J. Greg Doheny
NOTES: Animals II (Chordata Ch. 34)
Quiz Questions:
1. (Lemur, Chimpanzee, New World Monkey, Old World Monkey, Gorilla) Organize this list of
primates, starting with the primate that is the MOST closely related to humans, and ending with
the primate LEAST related to humans.
2. (Australopithecus afarensis, Homo sapiens, Homo erectus) Organize this list of hominins from
newest to oldest.
3. All members of the Phylum Chordata have pharyngeal slits early in development. What do
these slits eventually become in: A) Fish, and B) Humans?
4. Name one important gripping feature on the hand of a primate that distinguishes it from other
mammals.
5. Name an important gripping feature that the New World Monkeys have and the Old World
Monkeys do not have.
6. The world is estimated to be about 5 billion years old. Approximately how many years ago were
the earliest Homo sapiens believed to exist?
NOTES:
TERMINOLOGY
Eggs and Fertilization: Internal and vs. external fertilization.
1. Oviparous: eggs develop outside of female (may be fertilized inside or outside)
2. Ovoviviparous: Retain fertilized eggs in oviduct.
3. Viviparous: young develop in uterus.
Metabolism and Body Temperature.
1. Ectothermic: ‘cold blooded.’ Warms up by sitting in the Sun, cools off by sitting in the shade or
water (ie-reptiles).
2. Endothermic: ‘warm blooded.’ Can vary body temperature metabolically (ie-humans).
Branches of the Chordate Clade (see Fig. 34.2)
A) CHORDATES (in general)
1.Chordates: (animals with a dorsal nerve cord, or ‘notochord’)
BASAL animal example: Cephalochordata (lancet).
Common features of Chordates :Dorsal Nerve Cord (becomes spine in humans), Notochord (becomes
part of the spine in humans), Pharyngeal slits (become gills in fish and ears in humans), Post-anal tail
(becomes coccyx in humans).
2.Craniates: (Chordates with a head)
BASAL animal example: Myxini (Hagfishes)
Resulted from a duplication of one set of the Hox genes.
3.Vertebrates: (Craniates with a backbone)
BASAL example: Petromyzontida (Lampreys)
Resulted from duplication of Dlx transcription factor genes.
4.Gnathostomes: (Vertebrates with a jaw, teeth, and a cartilage skeleton)
BASAL examples: Chondrichthyes (Sharks, rays)
5.Ostechthyans: (Jawed vertebrates with a mineralized skeleton)
BASAL examples: Actinopterygii (Ray-finned fishes). Have swim bladders.
6.Lobe-Fins: (Ostechthyans with swim bladders and lungs.)
BASAL examples: Dipnoi (lung fishes).
Lung fishes have lungs and swim bladders. Gave rise to the tetrapods.
7.Tetrapods: (Having four limbs with digits)
a. Amphibians: external fertilization of eggs, oviparous development. Young amphibians (ieTadpoles) look like fish (water dwelling herbivores with no legs, gills and a tail), but develop into
land dwelling carnivorous (insectivores) tetrapods (frogs). Eggs dry out easily, and are not suited
to land dwelling.
b. Amniotes: full time land dwellers that have developed special egg structures to prevent
desiccation of eggs. (Four special membranes: Amnion, Chorion, Yolk Sac and Allantois.)
i.
Reptiles: are ectothermic, lay eggs, have b-keratin scales (or feathers). Most are extinct.
ii.
Synapsids: Mammals. Endothermic. Have same amniotic egg design, but development
takes place inside the mother instead of outside. Also have hair and mammary glands
(produce milk for young).
B) MAMMALS
Mammals (Synapsids) are endothermic, have hair (although some have lost it), nurse their young with
mammary glands (milk), and have differentiated teeth (ie- incisors and canines for tearing, and
premolars and molars for grinding).
Three lineages of mammals:
a. Monotremes: mammals that lay eggs. (ie-the platypus)
b. Marsupials: mammals with a pouch. Young only spend their early development inside the
mother. Are born very small, and finish development in their mother’s pouch. (ie-Kangaroo,
Wombat, Koala)
c. Eutherians: produce a more complicated placenta, spend a longer time inside their mother. (ieprimates)
Four Eutherian Clades:
1. Includes the following Orders:
a. Proboscidea (ie-Elephants)
b. Sirenia (ie-Manatees)
c. Tubulidentata (ie-Ardvarks)
d. Hyracoidea (ie-Hyraxes)
2. Includes the following Orders:
a. Xanthara (ie-Sloths, Anteaters, Armadillos)
3. Includes the following Orders:
a. Rodentia (ie-Rats, Squirrels, Porcupines)
b. Lagomorpha (ie-Rabbits, Hares)
c. Primates (ie-HUMANS!)
4. Includes the following Orders:
a. Carnivora (ie-Dogs, Cats, Bears, Otters, Seals)
b. Cetartiodactyla (ie-Goats, Cattle—hooved animals)
c. Cetaceans (ie-Whales, Dolphins, Porpoises)
d. Chiroptera (ie-Bats)
e. Eulipotyphla (ie-Mols, Shrews)
C) PRIMATES (Figure 34.43)
Originally arboreal (living in trees), flat face, long arms, opposable thumbs (for gripping), large brains,
complicated social structure. New World monkeys and Lemurs also have a prehensile tail for gripping,
which other primates do not have. Humans (Genis Homo) are most closely related to Chimpanzees
(Genis Pan), sharing about 99% of the same genes. More primitive apes have a larger male/female size
ratio (ie-gorillas), indicating intense competition between males for females. More advanced parenting
strategies are believed to lead to smaller male/female ratios.
D) HOMININS (Figure 34.46)
Hominins are early species of humans (or common ancestors to humans and other apes) that are mostly
extinct. Earliest evidence of human species is about 5 million years ago (ie-Australopithecus afarensis),
with Homo erectus (upright-walking man) appearing about 1 million years ago, and Homo sapiens
(modern man) appearing about 150 000 years ago. Evidence of walking upright is inferred from the
position of the foramen magnum (hole in the skull where the spinal cord enters). Mammals that walk
on all fours have the foramen magnum at the back of the skull, and mammals that walk upright (iehumans) have it at the bottom of the skull.
PRACTICE QUESTIONS
Match the term to the definition:
a. Amniotes
b. Amphibia
c. Arboreal
d. Chondrichthyes
e. Craniates
f. Ectothermic
g. Endothermic
h. Eutherians
i. Foramen magnum
j. Gnathostomes
k.
l.
m.
n.
o.
p.
q.
r.
s.
Lobe-fins
Marsupials
Monotremes
Osteichthyans
Oviparous
Prehensile
Synapsids
Tetrapods
Viviparous
1. Animals that live in water or on land (ie-frogs)
2. Describes development inside the mother, as opposed to laying eggs outside.
3. Animals with four limbs.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Laying eggs outside the body to develop, as opposed to developing inside.
Another name for mammals. (One of two types of Amniotes, the other type being the Reptiles.)
Name for a New World monkey’s tail, that can be used to grip things.
Name for the hole in the skull leading to the spinal column.
Group of mammals that spend a longer period of development inside their mother. Has a more
complicated placenta.
‘Cold blooded.’ Cannot regulate body temperature by varying metabolism.
Descriptive term meaning to live in trees.
Animals having a head.
A group of mammals that completes their development in their mother’s pouch.
Group of mammals that lays eggs (includes the platypus).
Animals having jaws and teeth
Animal name meaning ‘cartilage fish.’ Includes the sharks.
Animals with calcified bones (ie-boney fishes)
Group of animals with both lungs and swim bladders.
‘Warm blooded.’ Can regulate body temperature by varying metabolism.
Animals that have special egg structures to resist desiccation (drying).
Classify the mammals!
a. Kangaroo
b. Platypus
c. Dog
d. Koala bear
e. Whale
f. Bat
g. Wombat
1. Which are marsupials?
2. Which are eutherians?
3. Which is a monotreme?
Matching mammal orders in the same clade:
a. Rodentia (rats, squirrels)
b. Chiroptera (bats)
c. Sirenia (Manatees)
d. Lagomorpha (rabbits)
1. Name two mammal orders in the same clade with the Primates.
2. Name one mammal order in the same clade with the Proboscidea (elephants).
3. Name one mammal order in the same clade with the Cetaceans (whales).