Chordates
Phylum Chordata
Chordates
•What is a chordate?
– 1. Has either a backbone or a
notochord (vertebrate)
– 2. Can either be an ectotherm
or an endotherm
– 3. Only 4-5% of animals are
chordates
What is a vertebrate?
• Animals with a backbone or
vertebral column (notochord)
• Have spinal cord- dorsal, hollow
nerve cord
• Front end of spinal cord develops a
brain
Sea
Squirt or
Tunicate
Lancelet
http://www.diverosa.com/categories/Ascidians.htm
Chordates
•Endotherm (warmblooded)
–Has a stable body
temperature
•Ectotherm (coldblooded)
–Can change body
temperature due to the
environment
Chordate Cladogram
Section 30-1
Mammals
Birds
Amphibians
Fishes
Nonvertebrate
chordates
Invertebrate ancestor
Reptiles
Chordates
• Vertebrate Classes
– Jawless Fish (lamprey, hagfish)
– Cartilage Fish (sharks, rays…)
– Bony Fish (salmon, catfish, goldfish..)
– Amphibians (frogs, toads…)
– Reptiles (lizards, turtles…)
– Birds (sparrows, hawks)
– Mammals (humans, whales,
dogs…)
What are Fish?
• Anything with gills, scales and fins…
• 1st fish were jawless
• Devonian Period - “Age of Fish”
• Fossil of a devonian fish
• With jaws and armored plates
http://www.fossilmuseum.net/EdResources/FishImages.htm
• Fish have a two chambered heartblood is passed over the gills where
it picks up oxygen
Respiration
• Water passes over GILLS, oxygen is
added
• Some fish have gill covers OPERCULUM
• (Some fish have special organs to
serve as lungs; lungfish)
Excretion
• Homeostasis: maintaining balance,
internal conditions (in the case of
fish, water balance)
• Salt water fish tend to lose water
• Fresh water fish tend to gain water
• *This is why you can’t put a salt
water fish in a fresh water tank.
Other Fish Adaptations
• Fish fins help stabilize the fish and
propel it forward
• Swim Bladder - maintains buoyancy
(like a balloon)
Reproduction
• Spawning- fish lay eggs that are
fertilized externally
Warm Up
• 1. What are the steps of complete
metamorphosis?
• 2. What are the stages of
incomplete metamorphosis?
• 3. What is an open circulatory
system?
• 4. How do bivalves move and feed?
Class - Amphibians
Amphibians
• Amphibian- means “double life”
– Why?
•After beginning their lives in
water, most amphibians spend
their adulthood on land,
returning to water to reproduce.
(Lose gills and acquire lungs)
• http://video.nationalgeographic.co
m/video/player/animals/amphibian
s-animals/frogs-andtoads/frog_greentree_lifecycle.html
Amphibians
• 3 types/orders:
– Anura (frogs and toads),
– Caudata (salamanders and newts),
and
– Gymnophiona (caecilians, limbless
amphibians that resemble snakes)
• What’s the difference between a
frog and a toad?
– 1. Many toads have lumps behind their
eyes that contain poison that oozes out
when they are attacked.
– 2. Skin• Frogs are moist and smooth
• Toads are dry and bumpy
Frog Dissection
• What are the rules of lab?
• How should we behave?
• http://www.mhhe.com/biosci/genbi
o/virtual_labs/BL_16/BL_16.html
Frog Dissection- Mouth
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Reptiles
Reptiles
• An ectothermic vertebrate that has
lungs and scaly skin.
• Major Groups:
– Lizards
– Snakes
– Turtles
– Alligators
– Crocodiles
4 living orders are typically
recognized:
• Crocodilia (crocodiles, gavials,
caimans, and alligators): 23 species
• Sphenodontia (tuataras from New
Zealand): 2 species
• Squamata (lizards, snakes, and
worm lizards): approximately 9,150
species
• Testudines (turtles, terrapins and
tortoises): over 300 species
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Reptiles
• Unlike amphibians, which have a
thin, moist skin, reptiles have dry,
tough skin covered with scales.
– Skin protects and helps keep
water in their bodies.
Reptiles
• Lizards and snakes shed their skin.
• All snakes are carnivores but not all
lizards are.
• Turtles have a shell made from their
ribs and backbone.
Reptiles
• What is the difference between an
alligator and a croc?
– Alligators have broad, rounded snouts,
with only a few teeth visible.
– Crocodiles have pointed snouts, and
you can see most of their teeth.
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Birds
• Bird: an endothermic vertebrate
that has feathers and a fourchambered heart, and lays
eggs.
• The rule is:
– If it has feathers, it’s a bird.
Birds
• Feathers:
– Contour: one of the large feathers
that give shape to a bird’s body.
– Flight: long contour feathers that
extend beyond the body on the
wings and tail.
– Down: short, fluffy that are
specialized to trap heat and keep
a bird warm.
Birds
• Feed
– Capture, grip and handle
food, birds use their bills.
– Bills specify per species
– Internal storage tank called a
crop
– Birds do not have teeth, a
gizzard performs the grinding
function
Birds
• Adaptations for Flight
– 4 chambered heart
–Highly efficient respiratory system
–Lightweight bones with air spaces
Evolution of Birds…
• Create a Venn Diagramcharacteristics of reptiles, similarities,
characteristics of birds. Then come
up with your own explanation of the
evolution of birds.
The evolutionary origin of birds
has always been a subject of
considerable debate. Birds and
flying reptiles have delicate,
lightweight skeletons which do not
fossilize well - hindering studies on
how the birds evolved. The first
bird fossil to be found was a
feather, which was discovered in
1860 in a limestone quarry in
Bavaria. The feather was given
the name Archaeopteryx, which is
Greek for 'ancient feather'. A year
later an almost complete skeleton
of Archaeopteryx was discovered
in the same quarry, with the
feathers and other fine structures
preserved in minute detail.
The skeleton showed
several features which are
intermediate between
reptiles and birds,
suggesting that
Archaeopteryx and the other
birds evolved from a
dinosaur similar to the
Velociraptor featured in the
film 'Jurassic Park'.
Seven partial or complete
Archaeopteryx skeletons
have now been found, and
they are still among the
most famous, and
scientifically valuable,
fossils.
Mammals
• All mammals are endothermic
vertebrates with a 4 chambered
heart and skin covered with fur or
hair.
Mammals
•
•
•
•
•
•
All mammals have….
1. Hair or fur
2. Mammary glands (feed with milk)
3. Distinctive teeth
4. Highly developed brain
5. Extended care for the young
Mammals
• Three groups of mammals
– Monotremes
– Marsupials
– Placental mammals
Mammals
• Monotremes
– Mammals that lay eggs
– Two species:
• Spiny anteaters
• Duck-billed platypuses
Mammals
• Marsupials
– Young born alive at an early stage, but
continue to develop in a pouch
– Examples:
•Kangaroos
•Koalas
•Wallabies
•opossums
Mammals
• Placental Mammals
– Develop inside a mother’s body until its
body system can function
independently.
– Examples:
•Insect-eaters
•Flying mammals
•Primates
•Rodents
•Rabbits/hares
•Marine mammals
•Hoofed mammals