Examination One: Due Friday 11 February before midnight California Time
Notes: Although there is a minimum word count of 2,000 words for this exam, you will find that it is likely going to require more than
the minimum to fully answer the question. You may not copy or quote from any source. All information must be re-written in your
own words. Answer all questions. Point value: 100 points. Read the course Style Guide for detailed instructions of structure and
format. Exams must be submitted by the due date and time. Late Exams are NOT accepted without prior approval. Submit early
Do not include the question(s) on your essays and exams.
Question 01: What is an Animal? (25 points)
Describe the origin and diversification of animals from choanoflagellate ancestors among the Protista to the Porifera, Cnidaria,
Xenacoelomorpha, and Platyheminthes. Include in your answer:
a. the definition of “animal” that uniquely defines animals as different from all other organisms and how well sponges fit this
definition (or not)
b. a description of fertilization, radial, spiral, and superficial cleavage, and the formation of mesoderm during gastrulation.
c. a comparison of the nervous systems of Cnidaria and Platyhelminthes
Question 02: Feeding (25 points)
Describe prey capture, feeding and digestion of unicells, sponges, and cnidarians. Include in your answer:
a. cellular feeding by phagocytosis employed by protists such as Paramecium and Euplotes
b. the morphology and architecture of a sponge and the mechanisms of water flow, feeding, and food distribution
c. the morphology of Aurelia aurita and the mechanism of prey capture, digestion and food distribution of cnidarians
Question 03: Mesoderm and Coeloms (25 points)
Describe the nature and roles of mesoderm and the coelom by considering platyhelminths and annelids. Include in your answer:
a. the advantages and disadvantages of mesoderm
b. the embryonic development of mesoderm and the formation of the schizocoelom and the enterocoelom
c. the advantages and several functions of the coelom in annelids
Question 04: Animal Life Histories (25 points)
Describe the life histories of the following animals that undergo metamorphosis: Aurelia (Cnidaria: Scyphozoa), Pseudoceros
(Platyhelminthes: Turbellaria), and Fasciola hepatica (Platyhelminthes: Trematoda). Include in your answer:
a. a description of each of the different stages in the three life histories and the importance of asexual reproduction in Aurelia
and Fasciola
b. a description of the reproductive strategy that necessitates metamorphosis for each of the three
c. a description of the adaptations that are different in the larval stage and the adult stage for each of the three
Immediately following the essay, two lines below the last line of your essay, list all sources used in writing your essay to answer the
question. Do not use in-text citations and do not use footnotes. Simply list your sources in this “References” section. You must have
a References section with at least five references which you have used in preparing your answers: the course textbook, and at least
four additional sources. If you do not include a References section, you will lose 10 points (2 points for each missing source). Be sure
to include the References section with your submission to Turnitin. If you forget, you are able to re-submit until the deadline, but not
Submitting Assignments
It is your responsibility to assure that your essays and exams h