Biology 112 – Second Hour Exam                                       Name_____________________


MULTIPLE CHOICE. (50 points total) Circle the one alternative that best completes the statement or answers the question.


1. (2 points) What do Bacteria have in common with Archaea but not with Eukarya?

A) peptidoglycan cell walls  

B) unicellular structure  

C) transcription mechanism begins with formylmethionine  

D) absence of nucleus  

E) all of the above  



2. (2 points) Which are evolutionarily more closely related?  

A) Bacteria and Eukarya  

B) Bacteria, Eukarya, and Archaea are equally related to each other.  

C) Bacteria and Archaea  

D) Archaea and Eukarya  



3. (2 points) Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. How do these two groups differ?  

A) They use different electron acceptors.  

B) They use different sources of carbon.  

C) They use different sources of energy.  

D) They differ in the way they generate ATP.  


4. (2 points) Bacteria participate in the nitrogen cycle through which mechanism?  

A) denitrification  

B) nitrification  

C) decomposition  

D) nitrogen fixation  

E) all of the above  


4. (2 points) What problems do biologists try to solve with the help of bioremediation?  

A) degradation of pesticides  

B) detoxification of chlorinated compounds  

C) oil spills  

D) degradation of nitrate contaminations  

E) all of the above  


5. (2 points) Which of the following movements are matched correctly with the appendage that facilitates that movement in protists?  

A) cell crawling; cilia                                      B. cell crawling; flagella  

C) swimming; flagella                                D. swimming; pseudopodia  


6. (2 points) Which of the following characteristics is true of all protists?  

A) contains a nucleus  

B) photosynthetic  

C) has a cell wall  

D) very small  

E) unicellular  


7. (2 points) All eukaryotes have fully formed mitochondria.  

A) True                                                   

B. False  


8. (3 points) Consider the following data: (a) Most ancient eukaryotes are unicellular. (b) All eukaryotes alive today have a nucleus and cytoskeleton. (c) Most ancient eukaryotes lack a cell wall. These facts (a-c) support only one of the following conclusions. Which one?  

A) The first eukaryote was photosynthetic.  

B) The first eukaryote was anaerobic.  

C) The first eukaryote was capable of phagocytosis.  

D) The first eukaryote was very similar to a plant cell.  


9. (2 points) The protist that causes trypanosomiasis (African sleeping sickness) is transmitted to humans through the bite of a tsetse fly. Currently, insecticides are the most effective way to control tsetse fly populations and thus control the spread of trypanosomiasis. However, there is widespread fear that long-term use of insecticides may become less and less effective. Which statement best explains that fear?  

A) Natural selection could occur in the protist populations, so that they become able to inhabit a different insect host.  

B) Natural selection could occur in the protist populations, so that they become able to infect humans without an insect host.  

C) Natural selection could occur in the tsetse fly population, so that they become resistant to the insecticides.  

D) Natural selection could occur in the tsetse fly population, so that they could carry a different pathogenic protist.  


10. (2 points) Liverworts, hornworts and mosses are grouped together as the Bryophytes. Besides not having vascular tissue, what do they all have in common?  

A.            antheridia and archegonia for gamete production 

B.            swimming sperm for reproduction 

C.             ability to desiccate and rehydrate with no ill effects 

D.            low, sprawling growth habit 

E.            All of these answers apply. 



11. (2 points) What do seeds contain?  

A) female gametophyte and nutritive tissue  

B) male gametophyte and nutritive tissue  

C) embryo and nutritive tissue  

D) mature sporophyte and nutritive tissue  


12. (2 points) Which set contains the most closely related terms?  

A) megasporangium, megaspore, egg, ovule  

B) microsporangium, microspore, egg, ovary  

C) megasporangium, megaspore, pollen, ovule  

D) microsporangium, microspore, carpel, ovary  


13. (2 points) To biologists, the protists comprise all eukaryotes other than which groups?  

A) extinct forms  

B) those with cells containing a cytoskeleton and nucleus  

C) multicellular forms  

D) green plants, fungi, and animals


14. (3 points) Suppose a researcher for a pest-control company developed a chemical that inhibited the development of an embryonic mosquito's endodermal cells. How might this affect the adult mosquito?  

A) It wouldn't be affected at all.  

B) It would be vulnerable to injury, due to a weakened exoskeleton.  

C) It would have trouble flying, due to impaired muscle function.  

D) It would have trouble digesting food, due to impaired gut function.   


15. (2 points) Why do some researchers maintain that the limbs of all animals are homologous?  

A) Animal appendages are too complex to have evolved more than once.  

B) They all function in the same way-in locomotion.  

C) Homologous genes, such as Dll, are involved in their development.  

D) Their structure-particularly the number and arrangement of elements inside the limb-is the same.


Use the following information when answering questions 16 & 17:

Scarlet gilia (Ipomopsis aggregata) usually has red flowers in an inflorescence of up to 250 flowers. In certain populations in the Arizona mountains, however, the flowers range from red to pink to white. In early summer, most of the flowers were red. Six to eight weeks later, the same individual plants were still present; the flowers ranged from pink to white, and few red flowers were present. The major pollinators early in the season were two species of hummingbirds active during the day; they emigrated to lower elevations, and the major pollinator later in the season was a hawk moth (a type of moth). The hawk moth was most active at sunset and later, and it preferred light pink to white flowers after dark. When hummingbirds were present, more red flowers than white flowers produced fruit. When only hawk moths were present, more white flowers produced fruit (K. N. Paige and T. G. Whitham, Science 227 [1985]: 315-317).


16. (3 points) What is the significance of measuring fruit production?  

A) It is a measure of seed dispersal success.  

B) It is a measure of pollination success.  

C) It is an indication of predation on the seeds of the plants.  

D) It is easier than counting flowers  


17. (3 points) Late in the season, when only hawk moths were present, researchers painted the red flowers white. What would you expect?  

A) Red and white flowers would produce the same numbers of fruits.  

B) Unpainted red flowers would produce more fruits than white flowers would.  

C) Red flowers painted white would produce more fruits than red flowers would.    


18. (2 points) Which parasites live inside their hosts?  

A) ectoparasites                                                  B. endoparasites  

C) mesoparasites                                                D. none of the above  


19. (2 points) Diploblasts and triploblasts are terms that refer to 

A) the number of invaginations during development 

B) the number of cell types during development 

C) the number of tissue layers during development 

D) the number of head regions during development 



20. (2 points) Suppose some alien researchers visited Earth and collected the early ancestor of a phylum, then placed it in a large, stable habitat safe from predation and supplied with abundant food. The aliens maintain this setup for 500 million years. How might this organism evolve over time, compared to how it might have evolved on Earth? 

A) It would probably lead to less diversity of species than it would on Earth. 

B) It would probably lead to more diversity of species than it would on Earth. 

C) It would probably lead to a similar diversity of species as it would on Earth. 



21. (2 points) In what respect do humans differ from all other anthropoids?  

A) eyes on the front of the face                                 D) opposable thumbs

B) bipedal posture                                                           E) lack of a tail

C) diurnal activity  


22. (2 point) Endothermy is the ability to use the heat generated by the oxidation of sugars to maintain a high body temperature. What does it allow individuals to do?

a) sustain high levels of activity like flying or rapid swimming

b) function in cold habitats

c) hunt at night

d) all of the above



SHORT ANSWER (50 points total)                                  Name_____________________


23. (7 points) List the steps in the endosymbiosis theory for the origin of the mitochondrion. Be sure to include what each ŇpartnerÓ provides the other, and what did each receive in return?


Lynn Margulis hypothesized the following necessary steps leading to the engulfing of an aerobic bacterium by an anaerobic primitive prokaryote which led to the development of mitochondria.


The primitive eukaryote had to have a flexible cell membrane for engulfing food items (phagosytosis), an isolated, protected, membrane bound nucleus, cytoskeleton and a flagellum for internal structure and movement.


Once these were in place, the anaerobic eukaryote engulfed the aerobic bacterium, but did not digest it.


Once established insde the host (eukaryote) an endosymbiotic relationship developed, in which the host cell provided a protected environment for the endosymbiont (bacterium). The endosymbiont provided ATP and the ability to utilize oxygen (to become aerobic) to the host cell. The host cell was no longer poisoned by oxygen.


24. (8 points) What are the eight major trends in the evolution of animals? Just list them.

1.                     Bilateral symmetry

2.                     Cephalization

3.                     Triploblasty

4.                     Development of a coelom

5.                     Complete gut (mouth and anus)

6.                     Segmentation

7.                     Tissues, organs, organ systems

8.                     Homeostasis


25. (6 points) Protostomes and Deuterostomes are the two main branches in the phylogeny of complex animals. The fundamental differences in these two lines start with embryonic development. Describe two of the main differences between protostomes and deuterostomes with regard to embryonic development, including the one from which reflected in the names.


At least 2 of these:














SHORT ANSWER (50 points total)                                  Name_____________________


26. (6 points) Consider a puddle of water in which mosses, ferns, and an angiosperm are growing. In a drop of water taken from the puddle, you observed flagellated sperm. Explain why or why not each of the following statements is correct:


a)  The sperm could have been produced by the moss sporophyte.


Not correct, sporophytes produce spores, sperm are gametes





b)      The sperm could have been released by a pollen tube of an angiosperm.



Not correct, angiosperms donŐt release sperm to the external environment, sperm  move through the pollen tube within the flower, so fertilization is internal.




27. (7 points) What are the evolutionary benefits of a) flowers and b) fruits.  What might a cost be?



Flowers – attract pollinators, greatly increase chances for fertilization

Fruits – attract dispersers to move seeds around, greatly increase dispersal powers making it possible for new areas to be colonized




28. (7 points) Alternation of generations in plants always includes the same sequence of events, thought emphasis on each phase varies between types of plants. Draw a diagram of the generalized sequence for alternation of generations in plants. Be sure to include the following in the diagram:



eggs, sperm (gametes)







See diagrams in book





SHORT ANSWER (50 points total)                                  Name_____________________




29. (9 points) There are a numbers physiological problems presented by growth on land. Fill in the chart below with 3 of those challenges (1st column) and the adaptation(s) that allowed plants (use flowering plants as your model) and animals (use reptiles) to overcome the problem.


Must have 3 of the following 4 challenges. Full credit if have all the cell info. Subtract 1 point if have at least one correct in each cell, but not full.


Physiological Challenge

Plant adaptation (flowering plants)

Animal adaptation


Water management


Waxy cuticle, vascular system (xylem, tracheids also counts) (need only one of these)

Water-proof epidermis, vascular system

Gamete dispersal/reproduction


Pollen dispersed by wind,  or seed (protected embryo with nutrients)

Internal fertilization, amniotic egg

Respiration and gas exchange


Stomata (some will say guard cells – half credit for this)


Gravity – support


Lignin, vascular system (xylem, tracheids),  with turgor pressure (donŐt need turgor pressure to get points)

Skeletal system, limbs