Nonvertebrate Chordates, Fishes, and Amphibians
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Transcript Nonvertebrate Chordates, Fishes, and Amphibians
NONVERTEBRATE CHORDATES,
FISHES, AND AMPHIBIANS
Ms. Moore
3-1-13
WHAT IS A CHORDATE?
Phylum: Chordata
A chordate is an animals that has, for at least
some stage of life, a dorsal, hollow nerve cord; a
notochord; pharyngeal pouches; and a tail
that extends beyond the anus.
Hollow nerve cord: nerves branch off and connect to
organs
Notochord: long supporting rod that runs through the
body just below the nerve cord
Pharyngeal pouches: paired structures in the throat
region; can develop slits gills in some chordates
Tail: can contain bone and muscle; can be used for
motility
CHARACTERISTICS OF CHORDATA
MOST CHORDATES ARE VERTEBRATES
Figure 30-2
96% of all chordates are placed in the subphylum:
Vertebrata vertebrates
Vertebrae: backbone replaces the notochord in most
developing vertebrates; encloses and protects the
spinal cord
Part of endoskeleton
Grows as the animal grows
Made up of living and non living cells
NONVERTEBRATE CHORDATES
2 groups of Chordata do not have a backbone
Soft bodied marine animals
550 mya = ancestors!
Tunicates
Subphylum: Urochordata
Filter feeders
Open Circulatory
Lancelets
Subphylum: Cephalochordata
Small fishlike creatures
Live on sandy ocean body
Closed Circulatory
Diffusion through skin
MINI LAB
Draw a picture depicting a typical:
Tunicate (p 769)
Lancelet (p 770)
Label all parts
WHAT IS A FISH?
Fishes are aquatic vertebrates, most fishes have
paired fins, scales, and gills.
Fins = movement
Scales = protection
Gills = exchanging gases
EVOLUTION OF FISHES
The evolution of jaws and paired fins were important
developments during the rise of fishes.
First Fishes: 510 mya
The Age of Fishes: 505-410 mya
Jawless with armored plates
Ancestors of hagfishes and lampreys
Arrival of Jaws and Paired Fins
Filter feeders herbivores and carnivores
Fins attached by cartilage movement
Cartilage: strong tissue that supports the body; softer and
more flexible than bone
Modern Fishes
Ancestors of sharks and rays: cartilage
Bony fishes: bone
FORM AND FUNCTION IN FISHES
Feeding
Herbivores, carnivores, parasites, filter feeders, and
detrius feeders
Mouth Esophagus Stomach other organs
Intestines Anus
Respiration
Gills: located on either side of the pharynx;
made up of feathery filaments
Lungs: specialized organs to help in shallow
waters
Circulation
Closed circulatory system: single loop
Heart gills body heart
Atrium: large muscular chamber located in the
heart
Ventricle: thick-walled, muscular chamber;
pumping portion of the heart
Response
Fishes have well-developed nervous systems organized
around a brain
Cerebrum: voluntary activities; senses
Cerebellum: coordination
Medulla oblongata: fx of organs
Lateral line system: sense vibration/movement
Movement
S-shaped movement—muscles in the back
Fins increase surface area = faster
Swim bladder: gas filled organ that adjusts buoyancy
Reproduction
Eggs can be fertilized externally or internally
Oviparous: eggs hatch outside the mother’s body; salmon
Ovoviviparous: eggs stay in the mother’s body after
internal fertilization; guppy
Viviparous: embryos stay in the mother’s body after
internal fertilization; some sharks
GROUPS OF FISHES
Jawless Fishes
Class: Agnatha
No true teeth or jaws
Skeletons made of fibers and cartilage (keep notochords)
Include:
Sharks and Relatives
lampreys—filter feeders as larvae/parasites as adults
Hagfishes—detrius feeders; slime; 6 hearts; open; knots!
Class: Chondrichthyes (a.k.a. cartilage)
Include: sharks, rays, skates, and others
Bony Fish
Class: Osteichthyes
Skeleton made of bone
Almost all include ray-finned fishes
ECOLOGY OF FISHES
Aquatic Life
Freshwater = low salt
concentration
Ocean = high salt concentration
Movement/Migration
Anadromous fishes: ocean
dwellers migrate to freshwater to
breed
Lampreys
Salmon
Catadromous fishes: freshwater
fishes migrate to ocean to breed
European eels
MINI LAB
Draw the diagram of the fish, label all parts
(p774)
Draw the diagram of a fish brain, label all parts
(p777)
Fill out long study guide Agnatha
Osteichthyes
Complete handout
WHAT IS AN AMPHIBIAN?
An amphibian is a vertebrate that, with some
exceptions, lives in water as a larva and on land
as an adult, breathes with lungs as an adult, has
moist skin that contains mucous glands, and
lacks scales and claws.
Evoultion of Amphibians:
Bones became stronger = movement on land
Lungs = breath air
Sternum = protection of organs
FORM AND FUNCTION IN AMPHIBIANS
Feeding
Tadpoles: filter feeders or herbivores (algae) with
long intestines
Adult: meat-eating with shorter intestines
Sticky tongues to catch prey
Mouth esophagus stomach intestine
liver/pancreas/gallbladder colon cloaca (digestive
wastes, urine, eggs/sperm leave body)
Respiration
Larval: gas exchange through skin/gills
Adult: lungs some skin/mouth cavity (always
exceptions—lung less salamanders)
Circulation
Double loop system: first carries O2 rich blood from
heart to lungs and skin and back; second carries O2
rich blood from heart to rest of body and back
3 chambers: left atrium, right atrium, and ventricle
Excretion
Kidneys ureters bladder/cloaca
Reproduction
Frog eggs laid in water to undergo external
fertilization
Eggs hatch into tadpoles
Tadpoles gradually grow limbs, lose tails/gills, and
become carnivorous
Young adults move onto land
Movement
Larva: move like fishes
Adult: use front and back legs to move in a variety of
ways
Response
Brain much like a fish
Well developed nervous and sensory systems
Nictitating membrane: protects eye from
underwater damage/keeps moist
Tympanic membrane: eardrums on each side of the
head
GROUPS OF AMPHIBIANS
Salamanders (and Newts)
Frogs and Toads
Order: Urodela
Long bodies and tails; most have 4 legs
Larva and adults are carnivorous
Moist environment or underwater
Order: Anura
Jump! Frogs = long legs, near water; Toads = shorter legs;
moist woods, even deserts
Caecillians
Order: Apoda
Legless, carnivorous, live in water or burrow in moist soil,
many have fishlike scales in skin
ECOLOGY OF AMPHIBIANS
Must live near water
Some exceptions: desert amphibians have special
adaptations
Protection from predators
Skin colorings/markings
Poison glands in skin
Global decline
Amphibians are very susceptible to the environment
MINI LAB
Draw the following in your lab manual:
Figure 30-23 (p784)
Figure 30-24 (p785)
Notice the location of the organs
Use different colors to demonstrate the direction of
blood throughout the amphibian
Create a life cycle for an amphibian
Can use figure on p786