Bi 101 (Fall 2006) Animal Diversity II: Vertebrates Dr.
Dutton
The Tunicates, Lancelets, and Vertebrates:
Phylum Chordata
Chordate characteristics:
(1) a
_________________________ (stiff flexible anterior-posterior
rod made of cartilage, for muscle attachment) replaced by the bony backbone (vertebral column)
in vertebrates;
(2) a dorsal, hollow _________________________
_________________________ with an
anterior brain;
(3) _________________________
_________________________
_________________________ early in
development; and
(4) a _________________________ -_________________________
_________________________ early in
development
Why are humans chordates when we seem to lack all of the above
except a nerve cord?
During our development –
Figure 23-1
Invertebrate Chordates
_________________________ a
backbone
There are two group of
invertebrate chordates
1. Lancelets, fishlike
invertebrate chordates The adult organism exhibits all
the diagnostic features of chordates
2. Tunicates (larva) also
exhibits all the chordate features
For example, the adult sea squirt (a type of tunicate) has lost
its tail and notochord and has assumed a sedentary life
Vertebrate Chordates
_________________________ backbones!
The embryonic notochord
is normally replaced during development by a backbone (or vertebral column)
Vertebrates have an _________________________ of cartilage (sharks) or bone,
paired appendages (fins, limbs, wings), and large complex
_________________________ and
sensory structures
There are seven classes of vertebrates
Jawless fishes (class Myxini: marine
hagfish and class Petromyzontiformes:
aquatic lampreys) have _________________________ fins, cartilage skeletons,
no scales, _________________________ gill slits (Figure 23-3)
Cartilaginous fish (class Chondrichthyes:
sharks, rays, skates) have
_________________________ skeletons,
leathery skin with tiny scales, a
_________________________ -_________________________ heart, and rows of razor-sharp teeth (Figure 23-4)
Bony fish (class Osteichytes) have _________________________ skeletons,
gills, and _________________________
_________________________ (for buoyancy) and a two-chambered
heart (Figure 23-5)
Amphibians (class Amphibia: frogs
and salamanders) have limbs,
_________________________ _________________________, and moist skin (for gas exchange)
in adult forms
They have a _________________________ -_________________________
_________________________, and use external fertilization
with juvenile gilled forms developing in water
Reptiles (class Reptilia: lizards,
snakes, turtles, alligators, and crocodiles) have tough, scaly, waterproof
skin, and internal fertilization
They have shelled _________________________
_________________________ that
prevents desiccation of the embryos due to
presence of an internal _________________________ membrane that encloses the embryo
in a watery environment
Reptiles have efficient
lungs, a three-chambered heart, and limbs (except the snakes)
Birds (class Aves) have:
wings (flight),
_________________________ (heat insulation),
_________________________ bones,
internal fertilization,
amniotic eggs,
warm-bloodedness,
a _________________________ -_________________________ heart, and
a respiratory system with lungs and
air-sacs
Mammals (class Mammalia) have:
limbs (modified for running, swimming,
flying, grasping),
_________________________ (heat insulation),
warm-bloodedness,
a four-chambered heart,
highly developed brains,
internal fertilization,
_________________________ glands
(milk for feeding young offspring), and
embryonic development within female uterus
(except the egg-laying
_________________________ mammals: platypus,
spiny anteater)
Most mammals are _________________________ (they retain developing
young for long periods in a _________________________ placenta where gas, nutrient, and
waste exchange occurs)
However, the young of _________________________ mammals (opossums, koalas,
kangaroos) leave the uterus and crawl into a protective pouch to continue
development
Summary: Major Points
This Chapter has Covered:
Several phyla of Chordate
animals, including lancelets, tunicates, fish, amphibians, reptiles, birds, and
mammals
KNOW Table 22-1 - it is a summary of the major characteristics
of each phylum of animals discussed in this chapter