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Outline for Vertebrates – student notes – honors version
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I. Phylum Chordata
A. general characteristics (shared by all at some point during development; see p.
386)
1. dorsal, hollow nerve chord (other phyla have solid ventral nerve
chords)
2. notochord – flexible material located between the nerve chord and
the gut. (Degenerates into the discs between the vertebrates in
humans.)
3. pharyngeal slits – these are what look like "gill slits" in developing
mammal embryos. They develop into gills openings in fish, and into
other structures in mammals etc.
4. post-anal tail that does not include any of the digestive system.
B. subphyla cephalochordata and urochordata are little-known non-vertebrate
chordates.
· lancelets and tunicates (see fig. 18.14, p. 383)
EXPLORE the key differences between groups of vertebrates (American Museum of Natural
History) | Wild Finder - explore the world's biodiversity | Animal diversity web | National Biological
Infrastructure - a wealth of info on species and habitats | Encyclopedia of life | simulations of
dinosaurs and other prehistoric life (interactive site from BBC)
II. Subphylum vertebrata
A. characteristics – p. 390
1. vertebrae and internal skeleton
2. 2 pairs of appendages
3. head with highly developed sense organs
4. highly specialized brain
5. closed circulatory system
B. homeostasis - the process of maintaining a constant internal environment.
Vertebrate bodies are designed with specialized systems to help them do this:
1. nervous system - communication and integration of senses
2. endocrine system - chemical communication (hormones) that
regulate growth, levels of sugar and other substances in the blood, etc.
Involves the liver and various glands.
3. muscles/skeletal - movement
4. circulatory - brings oxygen and sugar to the cells and carries away
carbon dioxide and waste products.
5. digestive – enzymes break down food to sugar, which enters the
circulatory system.
6. excretory – kidneys, colon take care of cellular wastes and poisons
and solid waste
· reminder – all of these functions are controlled by enzymes and other
proteins, which are made by DNA.
C. class Agnatha (aye-nath-ah) fish without jaws (p. 391)
1. hagfish – scavengers
2. lampreys – blood suckers
D. class Chondrichthyes – cartilaginous fishes (p. 392)
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explore shark anatomy
check out the diversity - info on different species
1. skeleton made of cartilage
2. no swim bladder – "swim or float"
3. gills for oxygen
4. excellent senses
5. some bear live young; all have internal fertilization
6. excretory, digestive, and reproductive systems have a common
opening – the cloaca
E. class Osteichthyes - bony
fishes (see fig. 19.3 and p. 393)
1. members of the little-known subclass, lungfishes, can breathe air
and creep on their fins; they have been proposed as "transitions"
between fish and amphibians.
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another odd bony fish (in the same subclass) is known as the
coelocanth. These fish were originally known only from
fossils, and were found live more recently. They are known as
"fleshy-finned" fish. More here
pictures and info about other "odd fish"
2. swim bladder allows them to "hover" in the water
3. gills and two-chambered heart [You should be able to explain
circulation pattern; see fig. 23.2, p. 469
4. external fertilization and eggs
5. can be herbivores or carnivores
6. very streamlined body for motion in water; appendages not need to
support body but are used only to steer and maintain balance (fins)
7. divided into 24 orders
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New fish recently discovered in Indonesia
more pictures
and info
F. class Amphibia (see p. 396)
1. external fertilization and metamorphosis
2. most live in aquatic environments, and can breathe through their
skin.
3. orders:
a. frogs and toads (no tail)
b. salamanders (have a tail)
c. caecilians (no legs)
4. three chambered heart (less efficient). [You should be able to
explain circulation pattern; see fig. 23.2, p. 469
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how do frogs survive the winter??
explore amphibian embryology
Deformed amphibians are being
reported around the country. See
if you can find out why by
clicking above.
G. Class Reptilia (see
p. 397)
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more information and pictures
Life in cold blood: the life of reptiles and
amphibs
1. scaly skin (not slimy!)
2. internal fertilization; eggs are soft-shelled and amniotic
3. can live in wet or dry environments and even in the ocean
4. "cold blooded" or ectothermic – rely on sun’s energy to warm them
5. taxonomy – orders
a. turtles | browse the phylogeny (ancestry) of turtles
b. snakes and lizards
c. crocodiles and alligators
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explore crocadile anatomy
explore the different species of crocodilians
6. dinosaurs were reptiles (what makes a dinosaur a dinosaur?) check
out skulls of various tetrapods: anapsids | synapsids | diapsids
7. conventional theory says that birds evolved from reptiles/dinosaurs
(temperature control is one of the major differences)
8. reptile hip and shoulders are designed differently from those of
mammals and dinosaurs. This results in a different walking style.
More here
9. three or four chambered heart
more info and pictures
online bird guide
F. Class Aves – birds – p. 398
bird anatomy
Life of Birds
1. feathers
2. migration
3. light, hollow bones and
other adaptations for
flight.
4. muscles attached to a
strong, keeled sternum for
flight
5.amniotic eggs
ospreys - click here to see more
6. one-way breathing pattern
7. warm-blooded or "endothermic"
8. herbivores, carnivores, omnivores, and scavengers
9. four-chambered heart [You should be able to explain circulation
pattern]
10. migration
11. descended from reptiles? (Archaeopteryx)
12. very diverse group - 27 orders
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G. Class Mammalia –
p. 399
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Molossus rufus
(Microchiroptera)
Copyright © 1994, Nancy
Simmons (Tree of Life)
more info and pictures
fossil mammals
North American
mammals
Mammal exhibit at the
Natural History museum
Explore mammal
anatomy and behavior
1. mammary glands, inner ear bones, distinctive skulls, high level of
parental care
2. fur/hair
3. endothermic
4. four-chambered heart. [You should be able to explain circulation
pattern] (fig. 23.2, p. 469)
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
try your hand as a heart doctor at the Virtual Cardiology Lab
check out the visible human heart
check out the relationship between heart rate and size
5. varied sizes of teeth and size of intestines (fig 21.13) can be used to
infer diet
6. evolved from reptiles (Therapsids)
7. bear live young
8. jaw attached differently from reptiles – the same bone is a jaw
hinge in reptiles and the inner ear of mammals
9. taxonomy: (p. 390 and 399)
a. order Monotremes - platypus and echidna (spiny
anteater)
-mammary glands
-eggs
-cloaca
-no teeth
b. order Marsupials – young are born early and develop
further in pouch
-previously much more common in
South America
c. other mammal orders are all placental, meaning their
young develop fully before birth and receive
nourishment through a placenta
examples of placental mammal orders:
-rodents
-insectivores
-elephants
-primates
-carnivores (dogs, cats, seals, weasels)
-cetaceans (marine mammals)
-bats
-cows and deer (even toes)
-horses and rhinos (odd toes)
etc. – 17 total placental orders, plus 5 non-placental
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