| Amateur Radio | Amazon.com |Biology | Books | Chemistry | Data Sheets | Electronics | Math | Microscope | NASA-TV |
| Photography | Physics | Radio Astronomy | Robots | Science News | Space-Astronomy | Transistors | Search This Site |



Deuterostome

Characteristics of deuterostomes

Deuterostomes phyla

Characteristics of the echinoderms  

They develop from bilaterally symmetrical larvae that metamorphose into radially symmetrical, or in some cases into bilaterally symmetrical, adults (if the latter, they pass through a radially symmetrical stage first). Their radial symmetry is generally pentaradiality — based on five equal divisions of the body, like five slices of a pie.

They possess a characteristic series of internal fluid-filled body spaces or cavities, surrounding the viscera, that are lined by epithelia derived from the embryonic tissue layer that gives rise to adult muscle and connective tissue. One of these cavities has become modified for food collection and locomotion, and consists of a series of tubes, valves and extensible components called tube feet. This, the hydrovascular or ambulacral system, is found only in echinoderms. Generally, the tube feet face toward the substrate.

Echinoderms have a calcium carbonate endoskeleton composed of skeletal plates called ossicles found in the body wall. With the exception of those comprising the spines of pencil urchins, all skeletal plates in echinoderms are covered with tissue
 
Structures are involved to help echinoderms accomplish the following task  

Process

 Structures Involved

Respiration

A Echinoderm uses some of the bumps or spines on its surface to take in oxygen. It has a gill structure to take in the oxygen. It has a poorly developed respiratory system.

Ingestion

Mouth, esophagus

Digestion

Cardiac stomach, pyloric stomach, short intestine, digestive glands

Support

Spiny-skinned, endoskeleton  of calcium carbonate

Reproduction

A Echinoderm is a male or female. The males and females discharge their eggs and sperm into the water where they are fertilized. A female can release one hundred million eggs at once. If a piece of certain echinoderms is chopped off, a new piece or even a new echinoderm can re-grow.

Movement

Hundreds of tube feet, small hollow tubes each tipped with a suction disc, and powered by the water vascular system

Four chordate characteristics.

·       A notochord, a dorsal supportive rod extending the length of the body.  The notochord is replaced during development by a vertebral column in the vertebrates.

·       A dorsal tubular nerve cord.  In vertebrates, the nerve cord,  more often called the spinal cord, is protected by vertebrae.

·       Pharyngeal pouches, which become functioning gills in the invertebrate chordates, the fishes, and amphibian larvae.  In terrestrial animals, the pouches are modified for various other functions.

·       A postanal tail – as an embryo if not as an adult – a tail that extends beyond the anus.
 

          Diverstiy of Chordates

Name of organism

Subphylum

Class

Lancelet (Amphioxus)

Chrodata

Cephalachordata

Tunicates

Urochordata

Ascidiacea

Blue Shark

Vertebrata

Chonodrichtyes

Blueback Butterflyfish

Euchordata

Osteichthyes

Northern leopard frog

Vertebrata

Amphibia

Pearl River redbelly turtles

Vertebrata

Reptaillia

Scissor-tailed flycatcher

Vertebrata

Aves

Grey fox

Vertebrata

Mammalia

 

EXTERNAL ANATOMY OF THE FROG 
 

STRUCTURE

PART OF WHAT ORGAN SYSTEM

FUNCTION/DESCRIPTION

Nictitating membrane

Nervous system – optic nerve

A transparent part of a frog’s lower eyelid that moves over the eye to clean it and protect it.

External Nares

Respiratory

The nares are basically the nostrils of the frog. This is where
air primarily enters and exits the frogs respiratory system

Paired Appendages  (limbs)

Skeleton

Used for locomotion.

Eyes

Nervous system – optic nerve

Used for vision


INTERNAL ANATOMY OF THE FROG

STRUCTURE

PART OF WHAT ORGAN SYSTEM

FUNCTION/DESCRIPTION

MOUTH

Digestive

Entry way for food and air

Tongue

Digestive

Muscular structure attached to the front of the mouth which is extended to catch insects (its food).

Eustachian tube

Respiration

Equalize air pressure to the ears – mouth to ear tube.

Maxillary teeth

Digestion

Sharp teeth in the maxilla of a frogs mouth that function in holding captured prey.

Vomerine teeth

Digestion

Small projections in the top of a frog’s mouth that function in holding and captured prey.

Trachea (cannot see)

Respiratory

Short tube from glottis to lungs.

Esophagus (cannot see)

Digestion

Tube that connects the mouth and the stomach in a frog.

DISSECTION

 

 

Coelom

Digestion

Body cavity

Lungs

Respiratory

Exchange point where CO2 leaves and O2 enters the blood

Liver

Endrocrine

Secretes bile and processes digested food molecules carries in the blood from the ileum.

Gall bladder

Endrocrine

Sac which stores bile.

Heart

Circulation

Pumping organ of the circulatory system (has 3 chambers).

Atria

Circulation

Chambers that receive blood.

Ventricle

Circulation

Chamber of a frog’s heart that pumps blood out of the heart to the lungs and other parts of the body.

Stomach

Digestion

Stores food and mixes it with enzymes to begin digestion.

Small Intestines

Digestion

The principal organ of digestion and absorption of digested food.

Large Intestines

Digestion

Posterior organ of the digestive system which stores undigested food.

Cloaca

Reproductive – urinary - digestiion

Organ through which the products of the frogs digestive and urogenital system pass when discharged from the body

Pancreas

Endrocrine

Gland which secretes digestive enzymes into the duodenum.

Spleen

Endrocrine

Organ in the frog’s circulatory system that makes, stores, and destroys blood cells.

Kidneys

Urinary

Filter and storage for urine.

Fat bodies

Endrocrine

Masses of fat in the body cavities of frogs.  Needed for hibernating and mating

Testes

Reproductive

Male sex organs that produce sex cells (sperm).

Ovaries

Reproductive

Organs of the female reproductive system that produce the eggs.

Oviducts

Reproductive

Ovarie to cloaca duct.

Cloaca

Reproductive – urinary - digestiion

Organ through which the products of the frogs digestive and urogenital system pass when discharged from the body

Path of  food  through the digestive tract of the frog.
 
                   Mouth, maxillary teeth, vomerine teeth, esophagus, stomach, small intestine, large intestine, cloaca, anus
 
Which of these organisms is more closely related to man, a starfish or a crayfish?  Explain your answer.
 
                   Starfish/man.  Both are deuterostomes, a crayfish is a prototostome.
 

Why is the lancelet considered to be a vertebrate?

They posses all four characteristics of a chordate. While heartless (a ventral aorta does the pumping), the overall pattern of the lancelet circulation is similar to that of the vertebrates. There are separate male and female lancelets, but fertilization is still external. Basic features of vertebrate nervous system organization are found in the lancelet, a primitive chordate related to vertebrates. The lancelet is vertebrate-like, but much simpler.


Return to 101science.com