Transcript chapter_vertebrates

17A Body Systems in
Vertebrate Animals
 Introduction:
 Animals in the vertebrate group:
 Have vertebrae
 Skulls
 Skeletons that are alive (they are made if cells and require
energy to grow)
 Endoskeleton – made of a combination of bone and
cartilage
 Animals with endoskeletons have their primary support
inside their bodies
17A Body Systems in
Vertebrate Animals
 Bone gives vertebrates a strong support system
 Cartilage is also strong, but more flexible than bone
 Example: the end of your nose is cartilage
 Bone and cartilage are living tissues that grow with
the organism
 All skeletons have a vertebral column and skull
 Most vertebrates have ribs as well as other skeletal
structures supporting their limbs (may be fins, arms,
legs, or wings)
17A Body Systems in
Vertebrate Animals
 They also have joints between various bones and
cartilage pieces that permit them to move
 Muscles pulling on the bones or cartilage cause the
limbs to move at the joints
 Vertebrates testify to the greatness of God
 See Psalm 104:24-25
17A Body Systems in
Vertebrate Animals
 Vertebrates have more in common than just their
skeletal similarities
 God designed them with organ systems that meet
their needs for energy, response, movement, and
nutrition
 17A.1 Circulatory System
 Blood
 All vertebrates have blood (aka “the river of life”)
 Circulates throughout the body by the pumping of the
heart
17A Body Systems in
Vertebrate Animals
 It brings food to cells that are far away from the digestive
system
 Transports oxygen to and carries carbon dioxide from the
cells that are distant from the lungs or gills
 Wastes, control chemicals, and many other necessary
substances travel to and from the body’s cells in the
blood
 See Figure 17A-1
 Red – oxygenated blood – carries oxygen
 Blue – deoxygenated blood – had given oxygen away and
now carries carbon dioxide
 The blood of all vertebrates is red. They only differ slightly in
redness YOU DO NOT HAVE BLUE BLOOD!!
17A Body Systems in
Vertebrate Animals
 17A.1 Circulatory System
 Heart Chambers
 Vertebrate hearts contain spaces called chambers
 The walls of the chambers are made up of heart muscle
 The walls contract (squeeze), forcing the blood to move
out.
 One-way valves prevent the blood from returning to the
previous chamber
 Thus, a heart contracts over and over again, pumping
blood in one direction
 ARTERIES - blood vessels that carry blood AWAY from the
heart
 VEINS – blood vessels that carry blood TOWARD the heart
17A Body Systems in
Vertebrate Animals
 Different vertebrates have different numbers of
chambers
 Fish – two chambers
 One receives blood, the other pumps it to the body
 The blood that leaves goes first to the gill to become
oxygenated and then travels to the rest of the body
 Then eventually returns to the heart
 Most reptiles and adult amphibians – three chambered
hearts
 One collects oxygenated blood from the lungs
 Another collects deoxygenated blood from the rest of the
body
 Both of these empty into a third chamber where the two
types of blood are mixed
17A Body Systems in
Vertebrate Animals
 Birds and Mammals – four chambered hearts
 Chambers on one side only pump oxygenated blood
 The other side pumps deoxygenated blood to the lungs,
where it becomes oxygenated
 The oxygenated blood returns from the lungs to the other
side of the heart
 The oxygenated side pumps the blood throughout the body
 In healthy animals with four chambered hearts, oxygenated
and deoxygenated blood mix
17A Body Systems in
Vertebrate Animals
 17A.2 Respiratory System
 Gills
 Many vertebrates live their entire life underwater
 Gills take oxygen from the water and give off carbon dioxide
 Fish gills are shaped like tiny fingers and are richly supplied
with capillaries
 Blood circulating near the surface of the gills make them
appear red
 Capillaries – microscopic blood vessels in which blood often
exchanges gases and other materials
 In gills, deoxygenated blood becomes oxygenated
17A Body Systems in
Vertebrate Animals
 17A.2 Respiratory System
 Lungs
 Vertebrates that have lungs are able to breathe air
 Lungs are air chambers inside the body where blood can
obtain oxygen and give off carbon dioxide
 The lungs of reptiles, birds, and mammals are all different
 All lungs have many capillaries in which deoxygenated
blood becomes oxygenated
 Breathing moves air into and out of the lungs
17A Body Systems in
Vertebrate Animals
 17A.2 Respiratory System
 Lungs
 There are several different methods that animals use to
breathe
 Frog – fills its mouth with air and then forces the air into
its lungs
 Birds – move air through their lungs by using muscles to
control the size of connecting air sacs
 Mammals and humans – have diaphragms to help them
breathe
 Diaphragm – a thin later of muscle that separates the
chest chamber from the abdomen
17A Body Systems in
Vertebrate Animals
 17A.3 Nervous System
 Vertebrate nervous systems consist of two main
divisions: the central ad peripheral nervous
 Central nervous system – made up of the brain, which
is protected by the skull, spinal cord (which is
protected by bones of the vertebral column),
 Peripheral nervous system – made up of nerves which
branch off the central nervous system
 Sensory organs – sensory receptors scattered
throughout the body; they are a major collection of
sensory receptors and various supporting structures
17A Body Systems in
Vertebrate Animals
 17A.3 Nervous System
 Normally, a sensory organ only senses one
environmental factor
 Cranial nerves – nerves that branch from the brain
 These connect the brain with sensory organs of the head
 Spinal nerves – nerves that branch from the spinal cord
 These transmit impulses from the spinal cord to various
muscles and internal organs
 An organism’s reactions are controlled in the central
nervous system
 The central nervous system also controls many internal
processes
17A Body Systems in
Vertebrate Animals
 17A.4 Digestive System
 Food enters the body through the mouth and passes
through short, tubular esophagus into the stomach
 Muscles in the stomach walls squeeze the stomach
walls in and out to mix food with digestive enzymes
 When it is mixed, it moves into the small intestine
 In the small intestine has different enzymes to digest –
here food is broken down into molecules small enough
to be absorbed into the blood stream
 Two organs attached to the small intestine produce
additional enzymes: Liver and pancreas
17A Body Systems in
Vertebrate Animals
 17A.4 Digestive System
 Liver – produces a greenish fluid called bile, which
contains substances to help breakdown fats
 Bile released by the liver is stored in the gallbladder
until it is needed
 Pancreas – smaller organ that makes and releases
enzymes into the small intestine; these break down sugar,
starches, proteins, and fats
 Small intestine wound in curves and loops in order to fit
inside the animals body
 Large intestine – Food that cannot be digested passes
through here; also where excess water is absorbed.
 Undigested food leaves the digestive tract through the
anus
17A Body Systems in
Vertebrate Animals
 17A.5 Excretory System
 All vertebrates have kidneys to filter wastes from their blood
 Various waste products, including urea, are picked up by the
blood as it passes through the body’s tissue
 Kidneys have tiny tubes surrounded by capillaries
 Wastes leave the blood and enter the tubes
 In each kidney, the wastes flow through these tubes into one
large tube called the ureter
 Urinary bladder – where fluid is collected and stored before it
passes out of the body
 Birds – wastes pass out of the body with indigestible materials
 Some amphibians, most reptiles, and all mammals and humans,
wastes form urine
17B Fish
 Fish have fins, gills, and usually scales
 They live in fresh or salt water
 Ectothermic
 Ectothermic – their body temperatures change with their
surroundings
 A fish’s activity changes with the temperature
 17B.1 Fish Anatomy
 A fish propels itself by flexing its entire body
 Paired fins control movements
 Streamlined body shape to move easily through the water
 Some have a swim bladder (helps them float at a constant
depth)
 Swim bladder – an air filled organ that a fish uses to adjust to
different water depths
17B Fish
 17B.1 Fish Anatomy
 Fish have:
 closed circulatory system
 two chambered heart and blood vessels
 Blood pumped from the heart to the gills, through the
body, and back to the heart
 When blood passes through capillaries in the gills, oxygen
diffuses into the blood stream
 Using Figure 17B-1 – Trace the flow of blood through a fish
 Scales – overlapping to give the fish some protection
 They grow larger as the fish grows
 Lateral line – located on each side of the fish; a string of
sensory structures
 Can detect vibrations and pressure
17B Fish
 17B.1 Fish Anatomy
 Nostrils of a fish are NOT used for breathing; used for
smelling
 Most fish reproduce by spawning
 During spawning – female fish release millions of eggs which
are then fertilized by the male
 However, only a few survive to become adult fish
 Most fall prey to predators
 A few fish, guppies, reproduce by giving birth to live fish
rather than spawning
17B Fish
 17B.2 Fish Groups
 Jawless Fish

Have no jaws

No scales or paired fins

Worm-like creatures with skeletons composed of cartilage

Examples: lampreys and hagfish

Some species of lamprey are parasites, feeding on the body fluids of other fish

Hagfish are scavengers
 Cartilage Fish

Have endoskeletons made of cartilage

Have jaws, scales, and paired fins

Examples: Sharks, skates, and rays

Sharks have to keep water moving over their gills to ensure oxygen supply

They swim with their mouths open

They lack a swim bladder; instead they have a large oily, liver that is less dense than
water

Skates and rays rest on the ocean floor
17B Fish
 17B.2 Fish Groups
 Bony Fish
 The largest group of fish
 Includes: catfish, bass, flounder, goldfish, guppies, and
trout
 Endoskeleton made of bone
 Have jaws, paired fins
 Most have scales
 Some grow no longer than the width of a pencil; others
can reach 4.3 meters
 Some live in salt water; others in fresh
 Some warm water of the tropics; some frigid polar
temps
17C Amphibians
 Amphibians are ectothermic
 Live in water when young, but can live on land as adults
 The name comes from the greek word that means, “double
life”
 The name reflects two ways of living: in water and on land
17C Amphibians
 17C.1 Amphibian Development
 Metamorphosis – the process that changes an amphibian from
a gilled, aquatic organism to an air-breathing organism
 Young amphibians possess gills, but adults usually have lungs
 Gills and lungs are not the only organs used for respiration
 Most have thin, moist skin
 They can exchange gases through their skin (carbon dioxide
and oxygen) because they have tiny blood vessels close to the
surface
 Other changes metamorphosis includes:
 Two chambered heart to three chambered
 Growth of two pairs of limbs
 Gradual loss of a tail
17C Amphibians
 17C.1 Amphibian Development
 Though many adults live on land, they still live near water, for all
must return to water or moist places to lay their eggs
 17C.2 Amphibian Groups
 There are two major groups of amphibians – with a tail and without
 Tailless Amphibians
 Frogs and toads
 Frogs have smooth, moist skin and are usually near water
 Toads have rough, dry, bumpy skin and can be found far from
water
 Most lay jelly-coated eggs in water, where they are fertilized
externally
 They hatch to become tadpoles
 Tadpoles have gills and tails, but during metamorphosis, they
develop lungs and their tail gradually dissolves
17C Amphibians
 17C.2 Amphibian Groups
 Frogs and toads are ectothermic
 Temperature of their surroundings affect their activity
 They are less active in the cool (autumn and winter)
 Frogs usually bury themselves in the mud at the bottom
of a lake of stream during the winter
 Toads burrow in soft, moist soil
 Hibernation – the winter state of inactivity
 During hibernation, the animal’s life processes slow down
and energy supplies stored during the summer months
are used up
 A similar period of activity called ESTIVATION sometimes
occurs during hot, dry weather
17C Amphibians
 17C.2 Amphibian Groups
 Frogs eat insects, worms, slugs, snails, and other small animals
 It will attack anything that moves and is small enough to fit into its
mouth
 A large North American bullfrog will eat young water birds,
ducklings, young turtles, and even small fish
 Some will even eat other small frogs!
 A frog catches its food with its tongue
 Its tongue is short, thick, and attached to the front of the mouth
 When it sees food, it flicks its tongue out and stretches it out
 The tip of it is sticky
 When it touches food, the frog flips its tongue
 Frogs have two sets of teeth
 They do not use them for chewing, rather for keeping prey from
escaping
17C Amphibians
 17C.2 Amphibian Groups
 One set of teeth forms a ridge of tiny maxillary teeth
around the rim of the upper jaw
 The other set, the vomerine teeth, is located in two spots
at the front of the roof of the mouth
 The frog swallows by blinking and bulging its eyes
 When the frog closes its eyes, they push down into the
frog’s mouth, forcing the food back into the esophagus
17C Amphibians
 17C.2 Amphibian Groups
 Tailed Amphibians
 Salamanders
 They have tails into adulthood
 The young usually have gills and develop lungs later
 They also have thin, moist skin to help with gas exchange
 The Appalachian region of the US has more salamander
species than any other region on earth
 Most are small and less than 15 cm (6 in) long
 One Japanese salamander species can grow to be 1.5 m (5 ft)
long!
17D Reptiles
 All reptiles breathe air and do not experience the lifechanging metamorphosis
 17D.1 Reptile Characteristics
 Ectothermic
 Dry, scaly skin
 Lay eggs with leathery shells
 Most have a three-chambered heart – but one chamber is partially
divided
 The have lungs their entire lives
 Can be found in both wet and dry environments
 The scaly skin protects it from drying out
 The leathery eggs allow eggs to be laid on land far from water
 They fertilize eggs internally, within the female’s body
17D Reptiles
 17D.2 Reptile Groups
 The most famous – extinct dinosaurs
 Living reptiles can be divided into four groups:
 Snakes and lizards
 Alligators and crocodiles
 Turtles
 Tuataras
17D Reptiles
 17D.2 Reptile Groups
 Snakes and Lizards
 Snakes have no legs, ear openings, and immovable eyelids
 Most lizards have four legs, ear openings, and moveable
eyelids
 Both shed their skin periodically in a process called
molting
 Snakes do not hear. They also have poor vision
 Their immoveable eyelids are actually clear scales that are
shed each time it molts
17D Reptiles
 17D.2 Reptile Groups
 What snakes lack in sight they make up in other sense
organs
 Snakes have a keen sensitivity to molecules
 When a snake flicks its tongue, it is sensing the air – helps it
to detect food or danger
 Some snakes can detect body heat of its prey
 Pit vipers – such as rattlesnakes – have small pits on their
heads that contain organs that can detect heat
 Snakes are meat-eaters
 Benefit to humans –
 Eat insect pests, rats, and mice
17D Reptiles
 17D.2 Reptile Groups
 Most snakes are nonpoisonous
 Poisonous ones inject poison through hollowed fangs or
grooved teeth
 Nonpoisonous coil around prey and squeeze!
 They are capable of swallowing prey much larger in diameter
 They swallow food whole – they cannot chew!
 They have double hinged jaws
 Its throat is elastic
17D Reptiles
 17D.2 Reptile Groups
 Snakes are found in almost every environment
 Most lizards are found in hot or warm environments; dry
 Lizards can grow quite large – komodo dragon – up to 10 ft!
 Some lizards can change skin color!
17D Reptiles
 17D.2 Reptile Groups
 Crocodiles and Alligators
 Can be found in and near shallow waters of warm streams,
rivers, swamps, and lakes
 Usually found in tropical and subtropical environments
 Few crocodiles venture into salty water
 Use their large tails to propel themselves through the water
 Raised eyes and nostrils allow them to keep them above water
while the rest of the body is submerged
 Diet includes: fish, turtles, various large and small mammals
(usually attacked while drinking), others of their own kind and
occasionally humans
 Alligators and crocodiles can be distinguished by their snouts –
 Alligators – broad, rounded snouts
 Crocodiles – narrow, pointed snouts
17D Reptiles
 17D.2 Reptile Groups
 Crocodiles and Alligators
 The alligator is found all over the southeast
 Crocodiles are restricted to southern Florida
 Turtles
 Sea turtles – live in the ocean
 Tortoises – live on land
 Terrapins – freshwater turtles that may venture onto land
 Sea turtles have paddle-shaped legs used in swimming
 Other turtles have clawed legs
 They have two hard, bony shells to cover their bodies
 The shell is composed of bony plates covered with large scales
 It serves as a good defense
 Some have a hinged lower shell to close tightly for protection