Chapter 11.2 - Fishes

And Invertebrate Chordates...

Invertebrate ChordatesOnly 2 invertebrate chordates

● Tunicates (sea squirts)

○ Interesting fact: They eat their

own _____, which controls

movement.

○ Adults are sessile and no longer

have a notochord or postanal tail

○ Filter feeders

Invertebrate Chordates● Lancelets

○ Filter feed and spend most

of their time buried in the

sand.

Characteristics of Fishes◻ Vertebrates

◻ Ectotherms

◻ Gills, Fins, and Scales

◻ Closed circulatory system

○ 2 chambered heart and a one loop

Circulatory System of Fishes● Closed

● One loop

● 2 chambered heart

○ _______ - receives

blood from body

○ _______ - pumps

blood to gills & body

Cellular Respiration

● In which cell organelle does it take place?

● What is the equation?

● What is the most important product?

● Why is this product important to the organism?

Oxygen in

◻ Water from mouth flows over gills

◻ Oxygen diffuses into blood vessels in gills

◻ Heart pumps oxygen-rich blood through arteries to body cells

Carbon Dioxide out

◻ CO2

waste diffuses out of cells and into blood vessels.

◻ Blood carrying CO2 (oxygen-poor

blood) moves through veins to the heart

◻ Heart pumps CO2 to gills where it is

removed from blood

Fins◻ Fins: thin membrane

stretched over bony supports

◻ Used for movement and keeping them upright

Or not...

Feeding

Reproduction◻ Most fish perform

external fertilization

◻ Some fishes, like sharks and guppies perform internal fertilization and give live birth

External FertilizationNervous and Sensory System◻ Fishes have keen senses of touch, smell, taste,

sight, (no ears, but can sense vibrations)

3 Major groups of Fishes● Fishes are categorized by:

○ Mouth structure○ Type of Skeleton

● 3 groups are:○ Jawless Fishes○ Cartilaginous Fishes ○ Bony Fishes

Jawless Fishes (Class: Agnatha)◻ 1st vertebrates on earth

◻ No Jaw and paired fins

◻ Circular mouth

◻ Smooth, scaleless skin

◻ Endoskeleton made of cartilage

○ Cartilage is a connective tissue and its more flexible than bone

◻ Freshwater and marine habitats

Only 2 Types of Agnatha Left!◻ Hagfish◻ Eel-like◻ Feed on dead or dying fish◻ Less than 1m in length◻ ~40 species

◻ Lamprey◻ Aggressive parasite◻ Saliva acts as an

anticoagulant ◻ ~41 species

Lamprey Attack

Cartilaginous Fish (Class: chondrichthyes)

Characteristics:○ Endoskeleton of _________○ Jaws w/ teeth○ Placoid scales (made of ____)○ Internal fertilization

Types of Cartilaginous fishes◻ Sharks

◻ Skates

◻ Rays

Cartilaginous Fish (Class: chondrichthyes)

Sharks● Rely on _________and ________ to

move water across gills● Not picky eaters● Keen sense of _____: Can _____ and

_____ blood - even 1 drop in 115 L of water

● Poor ________● Jagged _____ arranged in rows

Cartilaginous Fish (Class: chondrichthyes)

Rays● Flattened disc-like body● Gills on _______ side● Wing-like pectoral fins● Obtain ______ by taking in water

through small holes located behind their _____.

● Hunt fish, mollusks, and crustaceans living on the ocean floor

Cartilaginous Fish (Class: chondrichthyes)

SkatesSimilar to rays, except they ___ ____.

Bony Fish (class: osteichthyes)◻ Jaws

◻ Scales

◻ ____ covers over the _____ chamber.

◻ Endoskeleton made of ____.

◻ __________ fertilization

◻ Bony plate-like ______

◻ ____ _______ for balance and buoyancy

◻ Freshwater and marine habitats

◻ __% of all fish species!

Swim Bladder◻ Internal, gas filled sac that helps with stability at different

depths.◻ Moving air into their swim bladder makes them ____.◻ Releasing air from their swim bladder makes them ____.

Swim Bladder Math◻ A catfish weighs 2.5 kg and has a volume of 2.0 L.

What is the density of the fish?

◻ If the density of water is 1 kg/L, will the fish sink or float?

◻ If the fish wants to move to the surface to eat a bug, what will it have to do to its swim bladder?

Swim Bladder Math◻ If a fish weighs 30 kg and has a total volume of 15 L, will it sink

or float? Assume water has a density of 1 kg/L.◻ How much air (in L) will the fish have to add or remove from its

swim bladder to obtain neutral buoyancy (neutral buoyancy is a condition in which the average density of an object is equal to the density of the fluid it is submerged in)?

Evolution from Fish to Amphibian