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NONVERTEBRATE CHORDATES, FISHES, AND AMPHIBIANSMs. 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 Jawless with armored plates
The Age of Fishes: 505-410 mya 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:
lampreys—filter feeders as larvae/parasites as adults Hagfishes—detrius feeders; slime; 6 hearts; open; knots!
Sharks and Relatives 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)
Order: Urodela Long bodies and tails; most have 4 legs Larva and adults are carnivorous Moist environment or underwater
Frogs and Toads 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) Notice the location of the organs
Figure 30-24 (p785) Use different colors to demonstrate the direction
of blood throughout the amphibian
Create a life cycle for an amphibian Can use figure on p786