Download The Vertebrates Phylum Chordata

The Chordates
–Dorsal nerve (Spinal) cord
–Notochord or backbone/vertebrae
–Tail (at some stage of the life cycle)
–Muscle Blocks
–Gill Slits (at some stage of the life
cycle
General Chordate Body Plan
Characteristics of the Chordates
• Notochord, dorsal hollow nerve cord, pharyngeal gill
slits, blocks of muscle, postanal tail
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Notochord (flexible rod - mesoderm)
Dorsal hollow nerve cord (endoderm)
Pharyngeal gill slits (all 3 germ layers)
Blocks of muscle
Postanal tail
Kingdom: Animalia
Phylum: Chordata
Order: Vertebrata
Class: ?
Major Classes of Vertebrates
Above: Class Amphibia: Includes all
amphibians (frogs, toads, salamanders)
Below: Class Aves: Includes all birds
Above: Class Reptilia: Includes the
reptiles
Below: Class Mammalia: Includes all
mammals
Class
Chondrichthyes:
Includes all
cartilaginous fish
ex. shark
Class
Osteichthyes:
Includes all bony
fish
Characteristics of All Vertebrates
• Coelomate and bilaterally symmetrical which
allows for complex body systems
• Have backbones with a protected spinal column
and endoskeleton
• Advanced central nervous system with large
brain with skull
• Cephalization
• Complex heart and circulatory systems
• Muscular system consists of mostly paired
masses
• Possess a special outer covering
• Have 1 or 2 pairs of appendages
• Are found on land and water
What’s the Difference?
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Bony Fishes
Skeleton is made up of
bone
Have a swim bladder to
regulate buoyancy
Perform external
fertilization and lay eggs
Have been very
successful because they
can reproduce in large
quantities
Cartilaginous Fishes
• Skeleton is made up of
cartilage
• Do not have a swim
bladders
• Perform internal
fertilization and bear live
young
Placoderms
Adaptations of Vertebrates
Class Amphibia
• Have gills and very
primitive lungs to
exchange gasses as
they live half of their life
in water and half on land
• Can also take in gasses
through their moist skin
• Lay eggs in the water
after sexual
reproduction which
develop into tadpoles
Crocodiles & Snakes
Reptiles
Turtles & Lizards
And Don’t Forget…
Dinosaurs were reptiles too!!
In addition to the amphibian
characteristics, reptiles also had the
following characteristics that allowed
them to be away from water for
longer, move better and grow larger:
• Dry scaly skin (prevented drying out of skin,
but also prevented breathing thru skin)
• Expandable rib cage (allowed them to
inflate their lungs to a large volume)
• Leather shelled amniote eggs (allowed them
to lay their eggs away from water)
• Copulatory organs (i.e. a penis - for internal
fertilization – the only way for sperms to get to
eggs when animals are living on land !!)
• Legs extending beneath the body (for better
locomotion & supporting more weight)
• 3 and 1/2 chamber heart (for better
separation of oxygenated and deoxygenated
blood – richer blood – more energy)
Adaptations of Vertebrates
Class Aves : The Birds
Adaptations for Flight
• Feathers
• 4 chambered heart
• Hollow bones for
strength without
weight
• Large sternum for
wings to attach and
put pressure
• Lungs and air sacs
are used to improve
gas exchange at thin
altitudes
Birds
Improvements over
reptiles include:
• Feathers
(for insulation and flight)
• Hollow bones
(lighter weight for flight)
• Warm blooded
(allowing for greater energy production)
• Air sacs
(for greater surface area and gas exchange)
• 4 chamber heart
(for complete separation of oxygenated and
deoxyg. blood = richer blood = more energy)
• Hard shelled amniote egg
(more protection from drying out and
from predators)
What’s the Difference?
Endotherms
• Warm blooded
• Body temperature
remains constant
regardless of external
temperature changes
• Endotherms can regulate
their metabolic rate and
are more independent of
their environments
Ectotherms
• Cold blooded
• Body temperature varies
with the surrounding
environment
• Cannot regulate their
metabolic rate very well
Characteristics of Mammals
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Warm blooded
Air breathing
4 legged vertebrates
Possess skin with hair
and sweat glands
Have teeth with a
jawbone
Fleshy lips
Diaphragm
4 chambered heart
Have a brain and middle
ear
Bear live young
Have mammary glands
Mammals
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The Cenozoic Era is known as the “Age of
Mammals”
• In addition to warm blood and a 4 chambered
heart, mammals also possess:
• Milk and Mammary glands
(to nourish young)
• Body hair
(for insulation)
• 3 groups: placentals, monotremes, and marsupials
Placentals
• Possess a placenta which supports the
growth of the embryo until birth – better
chance of survival
Monotremes
• Lay leathery eggs (like reptiles)
Echidna
(spiny ant-eater)
Marsupials
• Give birth to an immature live young - no
larger than a kidney bean
• Wombats, opossums, kangaroos, koalas
Ecological Roles of Vertebrates
• All are part of the food
chain
• Amphibians contribute to
wetland ecology, prey on
insects and devour algae
and dead plants
• Reptiles are predators of
pests
• Birds control insect and
vermin populations as
well as act as pollinators
• Mammals aerate soil and
are sensitive to
environmental changes