Transcript 28-Vertebrates and Fish

VERTEBRATES
Kingdom – ANIMALIA
Phylum – CHORDATA (means “cord”)
Subphylum – VERTEBRATA
(means “jointed backbone”)
I.
Evolution of
Vertebrates:
Mammals
Birds
Reptiles
Amphibians
Fish
Invertebrate
Ancestors
II.
Characteristics of ALL Vertebrates
A.
Hollow nerve cord
B.
Notochord – in embryos; in most
vertebrates is replaced by a backbone that
protects nerve cord & allows for greater
flexibility
C.
Postanal Tail – extension of vertebrae in
some vertebrates
D.
E.
Bilateral Symmetry
Endoskeleton
F.
G.
Coelom – a body cavity
Closed Circulatory System – blood
flows through vessels to/from heart
Complex Brain, Sense Organs &
Efficient Respiratory Systems
H.
I.
Chapter 28.1-2 – Fishes and Amphibians
Characteristics of ALL Fish
A.
Gills – respiratory
structures made up of
feathery gill filaments w/
tiny blood vessels
1.
Fish takes in water
thru mouth
2.
water w/ dissolved
O2 (not from H2O)
passes
countercurrent to
blood flow in the
gill’s capillaries
B.
2-chambered Heart:
1.
2.
slow blood flow
1 chamber receives deoxygenated
blood from the fish’s tissues
Other chamber pumps blood to
capillaries in gills, where O2 is picked
up & CO2 is dropped off
C.
D.
Sexual Reproduction – w/ egg & sperm
1.
can be released directly into water
2.
can be deposited on plants
Paired Fins – (ray or lobe) fan-shaped
membranes made of bone for
balance, swimming, & steering
1.
Lobed fins foreshadowed the
development of limbs for movement
on land & wings for flying (p. 831)
E.
Developed Sensory Systems
1.
Lateral Line – cartilage & bony fish
have this fluid-filled canal line to
sense vibration changes in the
environment
2.
3.
Eyes – allow fish to see objects &
differences in light and dark
Sense of Smell – detect chemicals
Lateral line system
Swim/Air bladder
Kidney
Scales
Urinary bladder
Reproductive organ
Fins
Stomach
Intestine
Gills
Liver
Heart
II.
Diversity of Fish (more species of fish than all other vertebrates combined)
A.
Superclass AGNATHA – “without jaws”
 Class MYXINI – hagfish
 Class CEPHALASPIDOMORPHI –
lampreys
1.
Jawless, cartilage skeleton, no scales,
internal fertilization
2.
Lampreys use a sucker to attach & drink
dying fish’s blood, teeth scrape flesh away
B.
Class CHONDRICHTHYES – “cartilage”
 sharks, skates, rays
1.
2.
Predators living on/near ocean floor
Jaws, cartilage skeleton, scales,
paired fins, internal fertilization
a.
Skates deposit fertilized eggs
on ocean floor (mermaid purse)
b.
Some sharks & rays carry
young inside their bodies
C.
Class OSTEICHTHYES – means “bony”
 walleye, sturgeon, bass, trout, perch, etc.
1.
Jaws, bony
skeleton,
scales, paired
fins
2.
3.
Air/Swim bladder –
depth is changed by
adjusting amount of gas
Most do external
fertilization called
“spawning”