NONVERTEBRATE CHORDATES, FISHES, AND AMPHIBIANSMs. Moore3-1-13

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 LABDraw 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