Transcript Kingdom Animalia Invertebrates Chordates & Fish

Zebrasoma flavescens
Petromyzon marinus
Branchiostoma lanceolatum
Galeocerdo cuvier
Pyura spinifera
Fish were the first
vertebrates on earth,
having the oldest fossil
known, dated about 550
million years ago. Fish
are related to the
evolution of all land
vertebrates, such as
reptiles, amphibians,
etc.
First invertebrates
appeared on earth in
the Proterozoic period,
about 650 million years
ago. From here, other
animals evolved from
invertebrates.
• Fish have bilateral symmetry, which means if it were to be cut in half,
the two parts would exactly be the same.
• In invertebrate chordates, urochordatas have radial symmetry, and
cephalochordata have bilateral.
• Fish are coelomates, or animals with a true coelom.
• Invertebrate chordates, such as cephalochordatas are also
coelomates.
• Fish are vertebrates, and have bones, such as back bones to
support its body. Some are also made of cartilage. They provide
protection and gives structure. They also have fins and a tail that
extends from the anus.
• Invertebrate chordates, such as cephalochordatas have no
backbone, but have a muscular notochord instead, and they are
unlike vertebrates.
• Some invertebrate chordates, such as tunicates require no special
organs for excretion, but use ammonia which diffuses into the sea
water.
• Others such as Lancelets have excretion organs such as
protonephridia.
• Fish maintain balance by retaining high concentrations of urea and
trimethyl amine oxide in their blood. The urea increases the salt
concentration to the level of sea-water. To keep salt concentrations
low similar to the environment, elasmobranchs secrete salt through
the kidneys and a special gland, the rectal gland, which connects to
the alimentary canal. The rectal gland concentrates and eliminates
both salt and chloride ions from the body tissues.
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A fish’s circulatory system carries blood from the heart through the gills and
to the body tissues before returning to the heart.
Its heart is a series of four chambers with deoxygenated blood running
through the heart to the gills without returning to the heart,
The heart chambers are separated by valves to prevent blood flowing in the
wrong direction during ventricular pumping.
In invertebrate chordates the blood is propelled by a distinct heart;
Unoxygenated blood is propelled forward by a vessel called the ventral
aorta. It then passes through a series of branchial arteries in the gills, where
gas exchange takes place, and the oxygenated blood flows to the body,
much of it returns to its origin via a dorsal aorta.
• Invertebrate chordates• Cephalochordatas- Water is taken through its mouth by
cilia, and then passes through the gill slits, which filters
out food particles, while water is passed on. Digestive
enzymes are released and digested in the iliocolonic ring.
• Urochordata- are mostly sessile, unable to move and
attached to rocks, which filter out food by having many
gill slits from the water like sponges.
• Fish can eat from algae, plants, to animals. Esophagus
are used, and most fishes have stomachs. The pancreas
excrete digestive enzymes and digest it. The intestines
absorb the food nutrition, and wastes are excreted
through the anus.
• There is a wide range of reproduction for fish.
• Fish can be males, females, or hermaphrodites.
•Basic reproduction for hermaphrodites is eggs produced in the ovaries, and
sperm produced in testes combine later when released into the body cavity.
•Most fish reproduce externally. Ovaries in the female produce eggs while Testes
in the male produce sperm. The eggs and sperm are released through an
opening behind the anus.
Some bony fishes, called livebearers yield live babies; the male injects sperm
into the female by using his anal fin. (internal fertilization) And then the female
carriers the eggs until they are released.
•Most Invertebrate Chordates are hermaphroditic.
They store there eggs inside their bodies until they hatch, while sperm is
released into the water where it fertilizes other individuals in with incoming water.
• Gills are the primary respiratory organ of fish.
• They are located lateral to the mouth cavity
• During ventilation water flows into the mouth across the
gill and through the gill slits.
• Urochordata- Filters out food and oxygen from the water
in gill slits
• Cephalochordata- Respires directly through the body
walls.
• Do sharks sleep? Fish don't sleep in the same
way that we do, but they have active and
inactive periods. Some sharks like the nurse
shark have been observed resting motionless on
the seafloor. Others have to keep moving in
order to breathe.
• Many species of open ocean shark need to swim
constantly to keep water flowing across their
gills, and to keep themselves from sinking.