Biology 102 Chapter 34
Deuterostomate Animals
1. List characteristics of echinoderms that distinguish them
from other animal phyla.
---radial symmetry as adults
---internal/external parts of body radiate from center
(often as five spokes)
---thin skin covers endoskeleton of hard calcareous plates
---possess unique water vascular system
--a network or hydraulic canals which branch into
extensions called tube feet that function for
locomotion, feeding, and gas exchange
---sexual reproduction by separate male/female
---radial adults develop from bilateral larvae
2. List and describe the unique characteristics of chordates.
---notochord; longitudinal flexible rod located between
the gut and nerve cord (dorsal)
--most important derived trait of Chordata and is UNIQUE
to that phylum
--lost in one subphylum; in others is replaced by skeletal
structures that provide support for body
---dorsal, hollow nerve cord; develops in embryo from plate
of dorsal ectoderm that rolls into tube located dorsal
to the notochord
---pharyngeal slits; pharynx is region just posterior to
mouth and opens to the outside through several pairs
of slits
---muscular postanal tail; a tail extending beyond the
anus; contains skeletal elements and muscles
3. Distinguish between the three subphyla of the phylum
Chordata and give examples of each.
---Urochordata contains the tunicates
--entire animal cloaked in tunic made of celluloselike
carbohydrate
--most are sessile marine animals
--are filter feeders
--commonly called “sea squirts”
--adults bear little resemblance to other chordates
--lose notochord during metamorphosis to adult
---Cephalochordata contains the lancelets
--bladelike shape
--marine filter feeders
--feeble swimmers with fishlike motions
--muscle segments develop from blocks of mesoderm called
somites
---Vertebrata; vertebrates have retained the primitive
chordate features while adding other specializations
--distinguishes vertebrates from urochordates and
cephalochordates
---possess neural crest, pronounced cephalization, a
vertebral column, and closed circulatory system
4. Describe the specialized characteristics found in the
subphylum Vertebrata and explain how each is beneficial to
survival.
---neural crest is group of embryonic cells found only in
vertebrates and contributes to formation of certain
skeletal components
--vertebrates show much greater degree of cephalization
than cephalochordates
--faster locomotion made possible by appendages favored
evolution of anterior skull with large brain and
highly developed sensory receptors
---skeleton including cranium and vertebral column as main
axis of body, replacing notochord as basic skeleton
--vertebral column serves as anchor for rigid, internal
skeleton for support and mobility
--skeleton composed of bone, cartilage, or combination
of the two
---two pairs of appendages attached to vertebral column
---anatomical adaptations support greater metabolic demands
of increased activity
--well-developed circulatory system driven by contractions of
ventral heart delivers oxygen to body cells
--ATP generation via cellular respiration
---internal organs suspended in large coelom
---vertebrates have closed circulatory systems composed of
ventral chambered (two to four) heart
---have several adaptations for feeding, digestion, and
nutrient absorption
5. Compare and contrast members of Agnatha, Chondrichthyes, and
Osteichthyes.
---Agnatha contains the lampreys and hagfish
--jawless vertebrates, cartilaginous skeleton, rasping
tongue, notochord persists throughout life, marine
and freshwater, living species lack paired appendages
--lampreys feed by attaching round mouth onto live fish
--hagfish are scavengers
--only vertebrate that is true osmoconformer
---Chondrichthyes contains the sharks, skates, rays, and
chimaeras
--cartilaginous fishes, cartilaginous skeleton, jaws,
respiration through gills, internal fertilization,
may lay eggs or give birth to live young, acute
senses, including lateral line system
--cartilaginous skeleton reinforced by calcified
granules
--a cloaca (common chamber for reproductive, digestive,
and excretory systems) is present
---Osteichthyes contains the “bony fish”
--have internal skeleton of bone rather than cartilage
--most species have outer surface covered with flat, smooth,
thin, lightweight scales (provides some protection)
--gills open into single chamber covered by hard flap called
operculum
--early lunglike sacs have evolved in most species into
swim bladders
-serve as organs of buoyancy
6. Describe the unique characteristics demonstrated by members
of the class Amphibia.
---Amphibia contains the caecilians, frogs and toads, and
salamanders
--some descendents of early fishes with jointed fins began
to use terrestrial food sources-->adapted to life on land
---stubby, jointed fins evolved into walking legs
--amphibians arose from ancestors shared with lungfish
--most amphibians live in water at some time in their lives
--have relatively small lungs and most exchange gases
through their skins
--most species confined to moist habitats because they lose
water rapidly through their skins when exposed to dry air
--must return to water to lay eggs
-egg enclosed by delicate membrane that cannot prevent
water loss in dry conditions
7. List the distinguishing characteristics of the class
Reptilia and explain any special adaptations to the terrestrial
environment.
---scales contain protein keratin which helps prevent
dehydration
---gas exchange via lungs (some turtles use moist cloacal
surfaces
---kidneys that can excrete concentrated urine
---dioecious with sexual reproduction and internal
fertilization
---most are oviparous and produce amniotic egg
--eggs released by female and development is external
of mother’s body
--amniotic egg with shell, three extraembryonic
membranes and embryo-nourishing yolk
---are ectotherms and use behavioral adaptations to absorb
solar energy and regulate its body temperature
---can only be defined by absence of features that
distinguish birds (feathers) and mammals (hair and
mammary glands)
8. List the distinguishing characteristics of members of the
class Aves and explain any special adaptations for flight.
---possess feathers made of keratin (light and strong)
---bones have honeycombed internal structure that provides
strength while reducing weight
---some organ systems reduced (females have only 1 ovary)
---no teeth (reduces weight); food ground in gizzard
---endothermic with insulation by feathers and fat
---lungs and air sacs
---very well developed nervous system
---wings are airfoils
---large pectoral (breast) muscles anchored to keel on
sternum (breastbone)
9. Distinguish between the subclass Prototheria and Theria.
---Prototheria contains a single order called Monotremata
--lack a placenta, lay eggs, and have legs that extend
from side
--no nipples on mammary glands
--duck-bill platypus and spiny anteaters
---Theria contains two major groups of mammals
--Marsupialia have ventral pouch in which young carried and
fed
--gestation is short and young must move to pouch after
delivery
--delayed implantation
--Eutherians often called placental mammals but not entirely
accurate (some marsupials also have placentas)
--give birth to more highly developed young
--NO external pouch
--extremely varied in form and ecology
--contains 16 major groups
10. List and describe the differences exhibited in marsupial and
eutherian mammals.
---covered in I.O. # 9 above
Additional Objective(s) for this chapter
11. List and discuss major traits that distinguish primates from
other mammals.
---primates probably descended from small arboreal (treedwelling) insectivores (moles/shrews)
---dexterous hands with opposable thumbs
---nails rather than claws
---eyes on front of face that provide good depth perception
---very small litters of offspring (usually just one) that
receive extended parental care