Animal diversity II
vertebrates
Echinoderms and Chordates
• 2 groups of animals w/ true coelom (body
cavity)
• mollusks, annelids, arthropods =
protostomes –first opening formed is
mouth
• echinoderms and vertebrates =
deuterostomes (this week)—mouth
formed 2nd after anus
Phylum Echinodermata (spiny skin)
•
•
•
•
•
•
•
•
•
•
sea stars, sea urchins, sea cucumbers, sand dollars
radial symmetry
endoskeleton (“test”) hardened by Calcium salts
water vascular system—water-filled canals & organs movement
tube feet for movement of sea star, involves adhesion to substrate
Sea stars have external digestion, where stomach comes out and its
enzymes digest prey (oysters, clams—remember which phylum and
class?)
capable of regeneration
Sea urchin
uses Aristotle’s lantern for chewing
herbivore, eats kelp
P. Chordata
• Characterized by having these 4 features
for at least part of their life cycles:
• dorsal hollow nerve cord
• pharyngeal clefts (gill slits)
• notochord (supporting rod)
• Post anal tail
3 subphyla of P. Chordata
• 3 subphyla:
• Urochordata--Protochordates (still
invertebrates)
• Cephalochordata—also protochordates
• Vertebrata--backbone
replaces/supplements notochords in adults
and brain encased in a skull
Subphylum Urochordates (protochordates)
• Loses 1 of the features (notochord) characteristic of
chordates as an adult
• All 3 characteristics in larval form
• Example is the tunicate
• free-swimming larval form, then settles on a substrate &
becomes immobile adult
• Adults w/ tough, outer skin (“tunic”—water-filled bag)
made of cellulose (what kingdom is this compound
normally found?)
• has incurrent (leads to pharynx) and excurrent siphons
• cilia bring water currents to pharynx, mucus traps
plankton/food, then goes to stomach
Tunicates (urochordates)
Subphylum Cephalochordata
Amphioxus (lancelet), marine, fish-like
all chordate characteristics present
looks like larval tunicate
remains free-swimming
has myotomes/muscles along sides for
movement
filter feeder
Amphioxus
Subphylum Vertebrata
• backbone supplements/replaces
notochords—several classes (Agnatha,
Chondrichthyes, Osteichthyes, Amphibia,
Reptilia, Aves, Mammalia)
Class Agnatha
• — jawless fish (other vertebrae have jaws)
•
appendages/feet are not paired
•
skeleton of cartilage
•
only 2 types are living—hagfish and lamprey
• Hagfish—bottom-feeding scavenger, sensory feeders
around mouth, when caught by predators secretes
mucous
• Lamprey—predators w/ teeth-like structures, sexual
maturity migrate to fresh water and die; larvae are filter
feeders for years. Larvae resemble amphioxus.
Hagfish
Class Chondrichthyes
• sharks, skates, rays
•
skeleton of cartilage
•
jaws, paired appendages and fins
•
jaws used to capture prey
•
paired fins for stable swimming and steering
•
internal fertilization in sharks
• Some are oviparous; young develop outside mother in
an egg case (mermaid’s purse—protects young)
• Some are ovoviviparous—egg case stays in mother and
babies hatch in mother
• None are viviparous (live birth)—we’ll see this later
Class Osteichthyes
• fish, marine and fresh water
•
skeleton of bone
•
most successful vertebrate
• advancements—bone, muscles attached
to fins (maneuvering and braking,
hovering), swim bladder to stay
afloat/buoyant (How do jelly fish do it?
Which form?)
Class Amphibia
•
•
•
•
•
•
—frogs, toads, salamanders
transition between fish and reptiles
“two lives”—land and water
Tetrapods/4 limbs
Open water needed for 1) reproduction and 2)
Rehydration (skin is respiratory organ and skin must be
moist to dissolve carbon dioxide so can leave the body
(remember, a product of aerobic respiration) and oxygen
(a substrate for aerobic respiration) can come into the
body.
• Metamorphosis starts w/ a tadpole
•
change from water to air breather
• gills disappear and have lungs for CO2/O2 exchange
Class Reptilia
• —lizards, snakes, turtles, crocodiles, extinct
dinosaurs
• tetrapods, except the snakes
• well-adapted to land: 1) independent of water for
reproduction, 2) amniotic egg, 3) penis
• Ectothermic (Remember: Does it use aerobic
metabolism to keep warm?)
• From this class, Aves and Mammalia developed
Rhinocerous iquana
Class Aves—birds
• most adapted to flight (exceptions include hens, chickens, ostriches,
penguins)
•
--forelimbs became wings
•
--feathers (for attracting mates and insulation too)
•
--hollow bones
•
--egg layers
•
descended from bipedal reptile (like dinosaur T. Rex)
•
resemblance—scaly legs and horny beaks
•
some monogamous (1 mate/life)
•
some polygamous (1 male and several females)
•
some polyandrous (1 female w/ several males)\
• Endothermic (How did they behave in our respiration
experiment?)—high metabolism gives off heat (so feathers for
insulation)
Class Mammalia
•
Endothermic
•
Hair
•
3 part brain
• Specialized teeth—incisors (cut), canines (tear), &
molars and premolars (crush and grind) success of
class
•
Mammary glands (modified sweat glands)
•
Only animals to suckle young
•
(not all have nipples)
•
Shares amniotic egg w/ birds and reptiles
•
Carnivores, herbivores, omnivores
•
Reproductive patterns of Mammals
•
• 1) Monotremes—egg-laying, milk-soaked hair
(Duck-billed platypus and spiny anteater)
• 2) Marsupials—blind at birth and fully develop in
pouch (Kangaroos, Koalas, and Opossum)
• 3) Placentals (use placenta to deliver
oxygenated blood to young in mother). Placenta
from tissues of mother and young. Live birth
(Viviparous).
Monotremes
Marsupials
Placentals
Placentals
Placentals