Download Vertebrates Notes guide independent work reading passage

 “Vertebrates: Amazing Animals” Humans have many of the same kinds of bones that dinosaurs had. Human bones are
just smaller. Your backbone is very much like the one in a dinosaur skeleton. Animals with
a backbone are called vertebrates. They belong to the phylum Chordata. Most chordates
are vertebrates. Their backbones are segmented into columns of bones called verteBRAE.
The skeletons of all vertebrate embryos are made of cartilage. But as we grow, the
cartilage is replaced by bone. Only four to five percent of animals are chordates. Some
examples of vertebrates include: fish, amphibians, reptiles, mammals, and birds.
Vertebrates such as birds and mammals are able to warm their bodies by capturing
energy released by the chemical reactions in their cells. Because of this unique feature,
they are able to maintain a constant body temperature even if the temperature of the
environment changes. For this reason they are called endotherms (--or warm-blooded
animals). Reptiles, Fish, and Amphibians are ectotherms or cold-blooded animals These are
vertebrates that can not control their body temperature. Instead it rises and falls with
the temperature of the environment. As they become warm they become more active and
are able to hunt for food or even to escape predators.
Fish live in nearly every single aquatic habitat imaginable They “are the most
numerous” of all vertebrates. Fish are aquatic vertebrates characterized by having fins,
scales, and gills. They were the first vertebrates to “evolve”. Fish take in oxygen rich
water through gills and remove oxygen poor water through gill slits. “ALL”fish have
a closed circulatory system, a four chambered heart, and a swim bladder that controls
buoyancy.Most are egg laying and move by contracting opposite muscles. (cartilaginous
fish do not have a swim bladder). Three Adaptative features of some fish are that fish
are able to float because they have a “swim bladder”. It traps gas inside their body in
order to regulate their vertical position and help them float. They have the ability to
swim. A streamlined shape and muscular tail enables them to move rapidly through the
water; pairs of fins allow them to maneuver easily left or right, up or down, and
backward and forward. Finally, they have a Lateral line system: consists of a row of
sensory structures that run the length of the body and connected by nerves to the brain.
This allows them to detects vibrations. There are three existing classes of fish today:
Jawless Fish, Cartilaginous Fish, and Bony Fish.
Jawless Fish were the “first fish”. They haves mouths with soft tissue and no “true
teeth” Jawless fish are eel-like, and have smooth, slimy skin, and a round “jawless
mouth”. These fish have a skull, brain, and eyes. But they do not have a lateral line
system. Examples include: lampreys, and hagfish. Lampreys are - free living or parasitic;
adapted for sucking blood and body fluids of other fish does not have a stomach:
esophagus, nor a straight intestine. Hagfish technically, DO NOT HAVE a backbone like
other vertebrates. BUT they are classified in this group because they do have a skull just
like the other vertebrates do. These are bottom dwellers in cold marine waters and
scavengers of dead and dying fish on ocean bottom. They feed by sawing the fish with its
toothed tongue from the inside out – Yuck!! They are extremely flexible to avoid capture
or to clean the slime off after self-defense secretions. When not feeding they remain
hidden in burrows on the ocean floor.
Cartilaginous Fish have skeletons that consist entirely of cartilage, not bone. They are
“ectotherms” that have movable jaws and skeletons with paired fins. Examples include
sharks, skates, and rays. Sharks are scavengers that eat injured fish, carrion, garbage and
other waste from ships as well as animals such as seals, turtles, birds, whales, crabs, and a
wide range of fishes. The shark’s mouth has 6 to 20 rows of backward-pointing teeth.
They can detect blood from an injured animal as far as 500 miles away. They swim with a
side-to-side motion of their asymmetric tail fins. Rays and Skates are also examples of
cartilaginous fish. They can detect blood from an injured animal as far as 500 miles away.
They swim with a side-to-side motion of their asymmetric tail fins. Sharks are covered with
small triangular teeth-like “denticles”. They feel like sand paper. If you rub your hand in
the opposite direction (back to front) it can cut your hand very badly!! Skates are a family
of “ectothermic” flat-bodied rays found in warm and temperate seas. They have eyes
located on the upper surface of the body while the mouth and gills are located on the
lower surface. Their color makes them almost invisible because when another animal looks
down on them, they are camouflaged with the darkness of the sea bottom. When looked
up from underneath, the animal is camouflaged with the light from the sun.
Boney Fish include goldfish, trout, catfish, tuna, and cod. Unlike cartilage fish, bony fish
can float because they have a swim bladder which traps oxygen and other gases in the
blood stream. This also allows them to remain still or float in water for long periods of
time.
Amphibians are an interesting group of vertebrates. The word "Amphibian" comes from
the Greek word meaning ”double life". Amphibians can live in water and on land (have a
“double life”). Scientist think that amphibians evolved from bony fish particularly the
“Lobe-finned fish”. Amphibians are “ectotherms”. They have moist, smooth, thin skin with
no scales. This is an advantage when absorbing moisture and water through their skin. This
is also a disadvantage when losing moisture. Their feet are webbed and the toes lack claws.
They use gills, lungs, skin, and mouth cavities for breathing. Amphibians have many
prominent characteristics that are adaptations to a life spent both on land and in water:
They change from an aquatic larval stage to a terrestrial adult form. This transformation is
called metamorphosis. Their Larvae (babies) have a two-chambered heart; adults
have a three-chambered heart and a well-developed closed circulatory system. Amphibians
enter a state of dormancy when conditions are unfavorable. They often bury themselves in
mud or leaves, emerging when conditions are better. Such inactivity is called: Hibernation
when it occurs in the winter. Estivation is when it occurs in the summer. Their eggs lack
shells. They are usually laid in water or in a moist environment and fertilized externally.
Their eggs are usually called larvae. Biologists have identified about 2,375 living species of
amphibians and have classified them into four groups: “Frogs & Toads”, “Salamanders”,
“Mud eels and sirens”, and “Caecilians”.
Frogs and toads do not have tails. There are about 3,500 known species of frogs
and 300 kinds of toads. They are found on every continent except Antarctica. Some types
spend their entire life in or near water, but others live mainly on land and come to the
water only to mate. Some frogs and toads are climbers that dwell in trees or burrowers
that live underground. Frogs and Toads are different, because toads have dry, warty skin,
while frogs have smooth, wet skin. They are similar because both frogs and toads return to
water to reproduce. In nearly all species eggs are fertilized externally. The fertilized eggs
hatch into swimming larval forms called tadpoles.
Salamanders and other amphibians with legs and tails make up the group of "visible
tail” amphibians. Salamanders, have elongated bodies, long tails, and smooth, moist skin.
Salamanders are less able to remain on dry land, although some can live in dry areas by
remaining inactive during the day. Some aquatic species (mud eels & sirens) are
referred to as "rough mouthed” amphibians. Caecilians are highly specialized tropical,
burrowing worm-like amphibians that are often legless creatures. The caecilian male deposits
sperm directly into the female, and the female bears live young. This is called internal
fertilization.