Biology 103
(Extra Credit Worksheet)


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Detail your answers to these questions and click the submit button at the bottom to send your completed worksheet to PAL. In order to receive 1 extra credit points for this assignment, you must complete this worksheet and score 90% or better on the Online Quiz.

1. Applying the information from the “overview” module describe the chordates according to these six features:
a. symmetry              
b. cephalization        
c. digestive system   
d. body cavity           
e. segmentation        
f. development            

2. Name the four distinguishing characteristics of all chordates.


Invertebrate Chordates

3. Lancelets do not reproduce  . Many tunicates do reproduce asexually by 
    . Many tunicates are and fertilization is . Lancelets are gonochoristic and fertilization is  .

4. Both lancelets and tunicates seem to rely on  for gas exchange. Although lancelets are heartless, tunicates have short      hearts that seem to have very little to do with 

5 . Both lancelets and tunicates gain nutrition from their environment by .

6. Name the two phyla of chordates presented in this module, list the number of species in each group, and describe the distinguishing features of each.


Aquatic Chordates

1. Fish and amphibians do not reproduce, for the most part, although there area very few species in which the females can reproduce . Most fish and amphibians rely on fertilization.

2. Fish, larval amphibians and some adult amphibians have highly efficient . Active organisms require an efficient gas exchange system and an efficient circulatory system.

3. All adult amphibians are . Most fish are  feeders. Amphibians and fish have complex  digestive system. In almost all vertebrates there is adistinct division called the between the 
and the

4. Name the four classes of aquatic vertebrate chordates presented in this program, list the number of species in each group, and describe the features that distinguish them.


Terrestrial Chordates

1. reproduction with fertilization is, by far, the rule with terrestrial chordates. All jawed vertebrates have specilaized structures for the transport of  . Offspring are produced by the hatching of of by live of miniature adult forms

have the simplest respiratory system of the land vertebrates, more divided than but less than . Reptiles and mammals have lungs, organs that terminate in dead-end vessel rich sacs called where gas exchange takes place.

3. The muscular diaphragm of mammals separates the   into a cavity and an cavity. have the most complex and efficient respiratory system.

4. Almost all reptiles are but there are a few herbivorous among the and . Birds and mammals include species that subsist on a variety of food sources. Reptiles and birds tend to swallow their food , while most mammals use their highly specialized teeth to   their food before swallowing it.

5. Name the three classes of terrestrial vertebrate chordates presented in this program, list the number of species in each group, and describe the features that make them unique.