Download Phylum Chordata Class Fish

Phylum Chordata & Types of
Fish
Kingdom Animalia
Phylum Chordata
Subphylum Urochordata
Subphylum Cephalochordata
Subphylum Vertebrata
Class Agnatha
Class Chondrichthyes
Class Osteichthyes
Phylum Chordata
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“Chordates”
Contains
invertebrate and
vertebrate species
All have bilateral
symmetry
All at one point have
a notochord, dorsal
nerve cord, pharynx,
and gill slits
Notochord
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A long rod of
stiffened tissue
Not bone or
cartilage
Nerve Cord
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Tube found on the
dorsal side that runs
parallel to the
notochord and gut
Anterior end
enlarges during
development to
form brain
Pharynx
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A muscular tube that
acts in feeding,
respiration, or both
Gill Slits
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A means of
removing oxygen
from a liquid
environment for
respiration
Subphylum Urochodata
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Includes: Tunicates or
Sea Squirts
Similar niche to
sponges but far more
complex animal
Filter feeder, diatoms
and other bits of food
caught in gill slits
Leathery “tunic”
secreted and covers
the body
Subphylum Cephalochordata
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Includes: Lancelets (called
due to shape)
Shows the four distinct
characteristics of
chordates
Closed circulatory system
Respiratory gases diffuse
across the body
Filter feeders
Subphylum Vertebrata
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7 Current Classes:
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Agnatha – jawless fish
Chondrichthyes – Cartilaginous fish
Osteichthyes – Bony fish
Amphibia – Amphibians
Reptilia – Reptiles
Aves – Birds
Mammalia - Mammals
Characteristics of Vertebrates:
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Many chordata characteristics seen in embryo
stage
Nerve cord develops into a spinal cord and a
brain
Two Large Advances:
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Spinal cord is protected by a bony vertebrae
Brain is protected by a bony skull
Complex Characteristics
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Expansion of species began with the evolution of
a jaw developed from the structure supporting the
gill slits
This lead to the ability to hunt other animals and
thus led to advances in the nervous system and
other body system processes
More Complex Characteristics
● Development of fleshy
and skeleton fins that
became the starting
point for arms, legs, and
wings
● Evolution of gills
allowed for better
diffusion of oxygen
● Gills developed into
pouches then
developed into lungs
Quiz quetions
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What do all organisms is the phylum
Chordata have at some point in their
development?
What does the nerve cord develop into?
What do all vertebrates have?
What is the long rod of stiffened tissue
called?
What is the function of gill slits?
What type of symmetry do chordates
have?
Ichthyology
● The study of fishes
Class Agnatha
● “Jawless Fishes”
● Most primitive
fish
● Lacks jaws and
feed by suction
● Cylindrical and
elongated body
● Lack paired fins
and scales
Hagfish & Lampreys
● Hagfish
◦ Feed mostly on
dead or dying fish
● Lampreys
◦ Mostly freshwater
◦ Attach to other
fish and suck their
blood
Hagfish and lamprey dissection
Quiz Questions
What does the word “agnatha” mean?
● State the 3 things the class Agnatha lack.
● Which Agnatha feeds mostly on dead or
dying fish?
● What is the study of fish called?
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Class Chondrichthyes
● “Cartilaginous Fish”
● Skeleton made of
cartilage
● Movable jaws with
well-developed
teeth
● Rough sand paper
like scales made of
the same
composition of the
teeth
Ampullae of Lorenzini
● Can detect very weak electrical fields
● Used to locate prey and navigate
Lateral line
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The lateral line is present in most fish
and is used to sense tiny vibrations in
the water. It is situated just under the
skin (subcutaneous) on the snout and
along either side of the shark’s body. The
lateral lines are canals that are filled with
fluid. Tiny modified hair cells line its
walls and are instrumental in sensing
vibrations and movement.
Lateral line continued
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Interestingly, the lateral line can also locate odor plumes. These are 3dimensional structures that assist the shark (and other bony fish) to detect
prey as well as potential mates. Interestingly, when the lateral line of sharks is
covered up or chemically impaired (as is the case when treated with certain
antibiotics), they are often unable to detect these odor plumes or their
sensory perception is somewhat limited, despite the fact that their nostrils are
fully exposed and functional.
Usually, fish and sharks will use the combination of smell and turbulence
detection at the same time. This process is called "eddy chemotaxis". When a
person, seal or other animal moves through the water, they leave behind
them a wake (turbulence), which is infused with their body smell (odor). This is
referred to as an "eddy".
While it is optimal for the shark to be able to see its prey, it is really the
combination of the lateral line and its sense of smell that makes for prime
hunting abilities and opportunities for the animal. This is thought to be the
reason that sharks often bump and rub up against objects and even divers, as
it is believed to assist them to ‘taste’ whether it is suitable for consumption as
they move the object against their lateral line.
Sharks & Ratfish
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Sharks
◦ Adapted for fast
swimming and to be
predators
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Ratfish or
Chimeras
◦ Bottom dwellers
◦ Have long “rat-like” tails
Rays and Skates
● Rays
◦ Flattened bodies with
gills on the bottom of
their bodies
◦ Whip-like tail with
stinging spines
(venomous)
● Skates
◦ Very similar to rays but
without the long tail or
stinging spines
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https://www.youtube.com/watch?
v=xEpmQtQGay4 (facts about stingrays)
https://www.youtube.com/watch?
v=He24uTIoz-0 (giant rays)
https://www.youtube.com/watch?
v=iLwkfWuAMRo (Jonathan Birds Skates
and Rays)
https://www.youtube.com/watch?
v=vrkkQO9zVfA (bull shark Jonathan Bird)
https://www.youtube.com/watch?
v=vkkBEioUS8U (shark dissection)
Rays
Jonathon Bird Skates and Bullshark
Shark dissection
Quiz Questions
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What does “chondrichthyes” mean?
Describe the scales on chondrichthyes.
List the 4 organisms in this class.
Describe the difference between rays
and skates.
What is the function of the lateral line?
Electrical impulses are detected by
what?
Class Osteichthyes
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“Bony Fish”
Make of 98% of all fish
and over half the
vertebrates
Skeleton at least made
partially of bone
Thin, flexible,
overlapping scales
Mouth located at end
of body
Presence of gas-filled
sac called a swim
bladder
Body Shape
● Body shape is
varied and linked
to its lifestyle
● Fast swimmer
need elongated
bodies
Body Shape
● Short,
compressed
bodies good for
navigating tight
places like reefs
● Bottom dwellers
tend to have
flattened shapes
Body Shape
● Elongated shapes
are need for life in
narrow spaces
● Some have less
generalized
shapes
Body Shape
● Some shapes are
conducive to
camouflage with
their environment
Exterior Layer
Locomotion
● Fish swim with rhythmic side to side
motion of the body or tail
● Rhythmic contractions produced by
bands of muscle called myomeres
Locomotion
● Swim bladder – specialized organ
filled with gas that assists in floating
due to a heavier bone structure
(found in bony fish)
Pectoral Fins
● Oversized in sharks to provide lift
due to no swim bladder, provide
tight maneuverability in bony fish
Dorsal & Anal Fins
● Employed as rudders used to steer
and provide stability
Pelvic fin
● Help the fish turn, balance, and brake
Caudal (tail) fin
● Used in steering and force
production
Lobe-Finned Fish
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Link between water
based fish and land
dwelling amphibians
Developed
bone/cartilage
appendages that
allowed them to
move in mud and
shallow waters
Developed primitive
lungs as well
Digestion
● Food passed through esophagus into
the stomach for digestion and on
into an intestine
Digestion
● Pancreas, liver, and the pyloric caeca
secrete digestive enzymes
Respiratory System
● Fish get oxygen
that is dissolved
in the water
● They must get
water to flow over
gills to do this,
called irrigation
Gill Structure
The gill is supported
by cartilaginous or
bony structure
called gill arch
● Gill rakers are used
as filters to stop
food from entering
gills
● Gill filaments
contain the
capillaries
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Circulatory System
● Closed
circulatory
system
● Two chambered
heart
● Gas exchange
happens in the
gills
Lungfish
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Uses actual
lungs to breathe
and has reduced
gills
Regulating Internal
Environment
The blood of marine fish is less salty
than the water, therefore they lose
water through osmosis
● To replace it they must drink seawater
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Nervous System
Central nervous system consisting of
brain
● Highly developed sense of smell due to
olfactory bulb/sacs which open to the
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Nervous System
● Some bottom
feeders like
catfish have
whisker like
organs called
barbels
Lateral Line
● Unique sense
organ that
enables them to
detect vibrations
in the water
● Canals inside the
body connected
to surface by
pores
Seahorses and lungfish
National Geographic deep
water fish (long)
Fish Documentary
Quiz Questions
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What does “osteichthyes” mean?
What body shape do fast swimmers need?
What is the function of the swim bladder?
Why do sharks not need this organ?
What are lobe-finned fish?
What are gill rakers?
Describe the circulatory system.
What are the whisker like organs on some
bottom feeders called?
Endothermic or exothermic?