Download 7 Vertebrate Classes

7 Vertebrate Classes
Class
Main Characteristics
Jawless, cartilagenous skeleton,
Agnatha
notocord present, lacks paires
appendages, 2 chambered heart
Examples
Lamprey and
Hagfish
Cartilagenous skeleton, jaws,paired
Chondrichthyes
appendages, gills, no operculum, no Sharks, skates,
swim bladder, internal fertilization,
rays, chimearas
placoid scales, 2 chambered heart.
Bony skeleton, jaws, external
Osteichthyes fertilization, swim bladder, operculum,
ctenoid scales, 2 chambered heart.
Bass, trout, perch,
tuna
Appendages adapted for land
Amphibia
use,tadpole stage, respiration through Salamanders,
lung/skin, smooth moist skin, 3
newts, frogs, toads
chambered heart.
Reptilia
Scaly skin, respiration via lungs, lay
Snakes, lizards,
amniotic egg Partially divided septum. turtles, crocodiles
Feathers, forelimbs modified as
Aves
wings, respiration though lungs,
Owls, sparrow,
endothermic, 4 chambered heart,
penguins, eagles
amniotic egg.
Mammalia
young nourished by mammary
Monotremes,
glands, diaphragm, 4 chambered
marsupials, and
heart, hair, endothermic, viviparous
Placentals.
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Phylum Chordata
Chordate Characteristics:
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Notochord. All chordate embryos have a notochord, which
is a longitudinal, flexible rod of cartilage located between
the gut and the dorsal nerve cord. The notochord may
persist into adulthood in some chordates, but in many it is
replaced by the vertebral column. The spongy material in
between the vertebral bones is all that is left of the
notochord.
Dorsal Hollow Nerve Cord. The nerve cord of a chordate
embryo is formed from a plate of dorsal ectoderm that rolls
up into a tube. It is located dorsal to the notochord. This
nerve cord is unique due to its hollow structure. It will
develop into the chordate's central nervous system .
Pharyngeal Gill slits. These structures are openings of the
upper digestive tube in chordates. The pharynx is the area
just behind the mouth. During the embryonic stage of the
chordates these slits connect the outside to the pharynx.
Early chordates used them as devices for filter feeding. As
time progressed the slits became modified to function in
gas exchange.
Post anal Tail. Most chordates have a tail extending beyond
the anus. In many aquatic species the tail is equipped with
skeletal and muscular tissue for movement.
Subphyla of Chordata:
Subphylum Cephalochordata. These invertebrate chordates contain
all 4 phylum characteristics in their adult body. The lancelet
Brachiostoma is the characteristic organism of this group. The
animal wiggles into the sand , leaving its anterior end exposed. It
pulls in water through its mouth and traps the food on the mucus
of its pharyngeal gill slits. It has limited movement, using a (~)
sinusoidal pattern.
Subphylum Urochordata. The common organisms are called
tunicates. Most are sessile marine organisms. The organism has a
body plan similar to that of a clam. Water is drawn into the body
through an incurrent siphon; food particles are filtered out through
the mucus covered gill slits. The food then moves into the
intestine and the waste material is then passed out through the
excurrent siphon. The adults lose 3 of the chordate characteristics
as adults: Notochord, nerve chord , and tail.
Subphylum Vertebrata.
Cephalization, development of highly specialized sensory
structures and a highly specialized brain.
Vertebral column, The axial skeleton ( skull, ribs, and vertebra )
and the appendicular skeleton ( arms and legs, or wings, or
flippers ) is an internal living system.
Closed circulatory system. It is a closed system. The heart is
composed of a collecting chamber(s) and a pumping chamber(s).
The cells of the body exchange food and gases through tiny blood
vessels called capillaries.
The kidney is the main excretory organ.
Sexes are separate. Fertilization may be internal or external
depending on the species.
Respiratory organs include the gills, lungs, or highly vascularized
skin. Oxygen is carried to all parts of the body in a liquid called
blood. Hemoglobin is the main attractant of oxygen and is found
in the red blood cells.
Class
Agnatha
Chondrichthyes
Main Characteristics
jawless, cartilage skeleton,gill
slits, no swim bladder
Placoid scales, cartilage
skeleton internal fertilization,
Examples
Lamprey and Hagfish
Sharks, Rays, and
Skates
paired fins,
Osteichthyes
Bony skeleton, paired fins,
operculum, swim bladder
Tuna, Bass, Catfish,
Flounder
Smooth skin, no claws,
Amphibia
aquatic larvae, breathe
through lungs and skin
Reptilia
Amniote egg, rough,dry skin,
respiration through lungs
Frog, Salamander, and
Toad
Snakes, Lizards,
Turtles, and
crocodiles
Feathers, amniote egg,
Aves
extensive lung system, and
Birds
wings
Mammalia
Hair, diaphragm, mammary
Marsupials,
glands, and bear live
monotremes, and
offspring.
Placentals
The Classes of Fish
Class Agnatha: (Lamprey and Hagfish)
General Characteristics:
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Absence of jaws.
These organisms lack the paired fins (pelvic and pectoral).
Skeleton made of cartilage.
Round eel-like body with a compressed caudal fin.
Soft skin devoid of scales.
They lack a swim bladder and gill covers (operculum).
7 gill slits on each side of the head.
The lamprey are parasitic and the hagfish are scavengers.
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Ectothermic ( animals that cannot control their body temperature).
External fertilization. Oviparous ( egg laying)
Marine and fresh water species are found.
Lateral line
Two chambered heart
Gills used for respiration
No external ears
No eye lids
Class Chondrichthyes: ( Sharks, Rays, and Skates).
General Characteristics:
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Skeleton made of cartilage.
Body covered with triangular Placoid scales.
Ventral,subterminal mouth with several rows of triangular teeth.
Large caudal fin with the dorsal section larger than the ventral one.
Paired fins ( pectoral and pelvic), are stiff and nonflexable.
They lack a swim bladder.
Ectothermic
Internal fertilization. Ovoviviparous ( developing egg kept inside the
female for protection and does not live off of the parent).
Marine organisms only.
Lateral line
Two chambered heart
Gills used for respiration
No external ears
No eye lids
Class Osteichthyes: ( Tuna, Carp, Salmon, and Sturgeons).
General Characteristics:
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Skeleton made of bone
Lateral line
Two chambered heart
Operculum covering the gills.
Swim bladder
Ectothermic
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Paired fins made of rays and spines,or lobed fins lacking the rays and
spines.
Various types of scales (ctenoid,ganoid, or cycloid).
Marine and fresh water species.
Gills used for respiration
External fertilization. Spawning. Oviparous.
No external ears
No eye lids.
Fish heart
Fish Circulation
Fish Brain
1. Olfactory Lobes : Functions in smell.
2. Cerebrum : Functions in muscle movement, intelligence, instinct, and
will power.
3. Optic Lobes : Functions in eye sight.
4. Cerebellum : Functions in muscular coordination.
5. Medulla Oblongata : Functions in involuntary responses ( heart beat,
breathing, and digestion ).
6. Spinal Cord : Functions in transport of nerve impulses to and from the
brain.
Amphibians
Class Amphibia:
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Amphibians have smooth moist skin. The toad is an
exception with rough dry skin.
The majority of amphibians contain four limbs with no
claws on their digits (toes).
They contain a three chambered heart. Two atria and one
ventricle. There is a possibility of the oxygenated and
unoxygenated blood mixing in the ventricle.
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They are ectotherms. During extreme environmental
conditions they either hibernate (winter) or aestivate
(summer).
They carry on external fertilization. Their offspring develop
through a process called metamorphosis. Tadpoles (aquatic
larvae) resemble fish. Over a period of time they change in
form into the adult amphibian.
They respire through poorly developed lungs and moist
skin.
They contain a well developed muscular system.
The digestive system is adapted to digest whole prey,
swallowed by the organism.
Two kidney's rid the body of nitrogenous waste. The
amphibian liver carries on several functions: detoxifying
poisons, producing bile, and storing glucose in the form of
glycogen.
The cloaca is a sac that collects discharge from the large
intestine, urinary bladder, and gonads before it is
eliminated from the body.
Their brain is well developed and is attached to a dorsal
nerve cord.
Most amphibians contain three eye lids. Two are normal
and one is transparent.
These are the first animals to possess a pressure releasing
canal called the Eustachian tube. The tube connects the
mouth cavity with the tympanic membrane.
Orders of Amphibia:
Order Apoda. This order contains amphibians without legs.
Examples of this order are the caecilians. Most of these organisms
live in the moist soil, while some tropical species live in ponds
and streams.
Order Urodela. These are tailed amphibians. Included in this group
are the salamanders and newts. These animals contain a tail and
neck. Some of these organisms never develop lungs and must rely
on external gills.
Order Anura. Frogs and toads represent these tailless organisms.
Frogs use powerful hind legs for movement. Their long sticky
tongue is attached to the tip of the lower jaw. They exhibit a
variety of colorful skin, which is sometimes poisonous. Frogs live
in many areas of the world. The male is the only one of the
species that makes sounds.
Tadpole and Adult Comparison
Characteristics
Adult Frog Tadpole
Type of limbs
legs
fins
Heart chambers
3
2
Type of food
Carnivorous
Vegetarian
Respiratory structure Lungs and Skin
Gills
Reptiles
Reptilian Characteristics:
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The development of the amniote egg. Reptiles are
considered the first true land animals. It was this egg that
allowed the reptiles to conquer the land and begin a reign
that lasted hundreds of millions of years. The amniote egg
is a water proof structure composed of a shell, embryonic
membranes, and the living embryo. Starting after the shell,
the first extraembryonic membrane is the chorion. The
chorion aids in the exchange of gases between the
environment and the embryo. The allantois is a sac-like
structure that grows out of the digestive tract of the
embryo. It functions in gas exchange and collects metabolic
wastes from the embryo. The third membrane is a fluid
filled sac called the amnion. It surrounds the embryo and
the fluid it secretes cushions the embryo. The fourth and
final membrane is the yolk sac. The sac contains the food
for the embryo.
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A thick dry skin covered with scales made of a protein
called Keratin. Reptiles molt as they grow.
Reproduction is sexual with internal fertilization. Most are
oviparous, while some snakes and lizards are either
ovoviviparous or viviparous.
Respiration occurs through well developed lungs, and in
some turtles a moist cloacal surface.
Reptiles are ectotherms. Being ectothermic enables an
organism to survive on much less food than an endothermic
organism.
Most reptiles contain a 3 chambered heart with a partially
divided ventricle. Crocodiles contain a 4 chambered heart.
Reptilian Orders.
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Order Chelonia. Turtles are members of this order. They
developed from animals called anapsids during the
Mesozoic era. They show very little change from their
ancestral form. They contain 2 shells. The top shell is
called the carapace, while the lower shell is called the
plastron. Both shells are colored to help the turtle blend in
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with the 2 environments in which it lives. All turtles lay
their eggs on land. Turtles do not contain teeth, but use a
horny beak to grab and tear food. Turtles contain three
eyelids.
Order Squamata. Lizards and snakes belong to this reptilian
order. Lizards are the most abundant of this order. They
evolved from the diapsid group of primitive organisms.
They range in size from the large Komodo Dragon to the
small tropical geckos. Snakes are probably the most
interesting species of this group. They probably developed
from small burrowing lizards. They are void of legs,
eyelids, and ears. They are carnivores swallowing their
prey whole. Their glottis and gullet are at separate ends of
the mouth cavity. This allows the snake to breathe when
eating. They contain 2 rows of teeth on the upper jaw and
one row on the lower. The teeth are curved and pointed
back toward the gullet. This keeps the food moving in one
direction toward the stomach. The jaws are hinged in such
a way as to separate allowing the mouth to open wider than
usual when swallowing large prey. Some species are
venomous, either giving off a hemotoxin ( blood poison) or
a neurotoxin ( nerve poison). The tongue is used in the
sense of smell. Heat sensitive pits are a feature of some
venomous snakes, these allows the snake to home in on the
prey's body heat.
Order Crocodilia. Crocodiles evolved from the diapsid
lineage. These organism are found in most of the warm
regions of the world. They spend most of their time in the
water. They contain a 4 chambered heart and are the closest
living relative of the dinosaur.
Class Aves
General Characteristics:
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Birds are flight orientated organisms. Each part of its
anatomy is modified in some way to allow it to keep its
body light and energetic for flight.
Very active metabolism. They can eat, digest, and eliminate
the waste in a short amount of time. Their body
temperature is rather high 102-103 degrees F. They are
endotherms.
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They contain a four chambered heart.
Their skeleton is constructed of light weight bones
supported by an inner meshwork of bony material to give
extra support while flying.
The female loses one of its ovaries.
They have no teeth and their beak is made of a light protein
keratin.
They contain feathers, also made of keratin. There are three
types of feathers: down feathers which are used for
insulation, contour feathers which are colorful and used for
recognition, and keeping the body aerodynamic, and quill
feathers which are used for flight . These feathers are lost
periodically (molting).
They have an extensive air sac system attached to the
lungs. This reduces the weight of the bird and supplies the
needed air for a fast metabolism. It also is used to dissipate
the tremendous amount of heat built up from metabolism.
They develop from the amniote egg. Bird egg shells are
hardened with calcium carbonate for added protection.
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Birds that are ready to carry on life's duties upon hatching
are called precotial, while those that need further
development are called altricial.
They have a well developed nervous system. Acute vision,
and external ears.
Well developed muscles. The keel ,a part of the sternum,
allows large pectoral muscles to be attached to the skeleton.
Their forelimbs are modifies as wings. These wings are
homologous to the limbs of the reptiles, amphibians, and
mammals.
Their hind limbs are modified for various jobs based on the
structure of their claws.
Birds are an excellent indicator of the fitness of the
environment. They help keep the insect population down,
use rodents as a food source, help rid the environment of
dead and decaying organic material, and help pollinate
many types of plants.
Many birds migrate over long distances to find suitable
breeding grounds and protection from major climatic
changes.
Class Mammalia
General Mammalian Characteristics:
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Possess hair which is made of keratin. The evolution of
mammalian keratin is believed to be independent of
reptilian keratin. Hair provides insulation .
Endothermic. The majority of the heat energy is used to
maintain their high body temperature.
4 chambered heart.
Mammary glands are used to produce milk to nourish their
young. Female glands are the only functional glands.
The diaphragm is a muscle that separates the thoracic cavity
from the abdominal cavity.
7 cervical vertebrae (neck bones) are present in most
mammals.
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Most are viviparous though some are oviparous. An
extended gestation period (uterine development) is common
in most placental mammals.
Teeth are imbedded in the jaw bone and come in a variety
of forms.
Well developed brain.
Mammals developed from the therapsid ancestors during
the Triassic period.
Major Groups of Mammals:
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Monotremes. Characterized by the duckbilled platypus and
the spiny anteaters, lay eggs and maintain some reptilian
characteristics. They do not contain true mammary glands,
but produce a fatty sweat (milk) from glands in the skin.
The milk collects and drips down tufts of hair into the
offspring's mouth. They are found in Australia and New
Guinea.
Marsupials. These mammals contain a pouch (marsupium).
Opossums,koalas,kangaroos, and other examples live in
Australia as a result of the break up of the super continent
Pangea. The young are born during the early stages of
development. The new born crawls up to the mother's
pouch, where it clings on to a nipple and hangs there until it
fully develops.
Placental Mammals. These mammals are the most abundant
and diverse of the class. The placenta, a reproductive
structure, is housed in the uterus of the female. Here the
offspring receives all that it needs to develop into a fully
developed organism. This period of development
(gestation) varies with the species of mammal. Whales
gestate for 2 years, while a mouse develops in 21 days.
Chart of Placental Mammals
Order
Carnivora
Chiroptera
Characteristics
Eats meat, all teeth
are pointed
wings used for
Examples
cats and dogs , seals, walrus,
weasels, and martins
bats
flight, diet
includes insects
and vegetation
opposable thumb,
Primates
plantigrade foot,
usually one
man , apes, monkeys,tarsiers,and
lemurs
offspring at birth.
Edentata
Rodentia
Lagmorpha
Cetacea
Proboscidea
Sirenia
Perissodactyla
Artiodactyla
lacking teeth, large sloths, armadillos, South American
claws for digging
anteater
2 incisors on both
jaws, diastema
rats, mice, squirrels, beavers,
between incisors
gophers, and capybara
and premolars
4 incisor teeth,
canine teeth
rabbits, hares,pikas
lacking, short
stubby tails
flippers, opening
dolphins,whales,porpoises
on top of head
Great size,nose and
upper lip form
proboscis, upper
elephant
incisors are
tusks,thick
skin,scant hair
Herbivorous,
aquatic, no external
Manatees and dugongs
ears, flippers, no
hind appendages
Odd-toed,hoofed
forms,gall bladder
horses, donkeys,zebras,tapirs
lacking,
herbivorous
Even-toed, hoofed
Cattle,pigs,camels,deer,hippopotami
forms, herbivorous,
true horns or
antlers present