SC 139 - Second Exam 2001

ANSWER KEY

MULTIPLE CHOICE.


On the line to the left, place the letter of the choice that best answers the question.
Three Points Each. NOTE: "e" answers are never the correct answer.


                    1. The Earth's primordial soup
___D___          a. Was produced by the first bacteria
                        b. Was produced by the first plants
                        c. Was rich in oxygen
                        d. Was originally space dust
                        e. Was never a big seller for Campbell's

                            ...it was there before a, b, or c - it was there when the Earth formed...


                    2. Which trait can be found in all of the Kingdoms?
___B___          a. Food ingestion                 b. Evolution                 c. Cell nuclei
                        d. Photosynthesis                                     e. Slime

                            ...everything alive evolves, and there is at least one Kingdom that doesn't
                                    fit each of the other choices


                    3. Which is an acceptable species name?
___B___          a. pizzaus huttus                                 b. Burgurus kingius
                        c. Maccus Biggus                                d. hotdogius Charlius
                                             e. Couldn't we call it "Harvey"?

                            ...just following the basic capitalization rules...


                    4. Which event in Earth's fossil history comes closest to seeming a "Creation" event?
__A____         a. Cambrian Explosion                             b. Movement onto land
                        c. Ice ages                                              d. Dinosaur extinction
                        e. Isn't there some kind of science rule against this kind of question?

                            ...that's when all the animal groups just kind of "appeared"...


                    5. What classification system is set up so new "branches" of the family trees
                                are tied to particular traits?
___C___          a. Arboreal                     b. Systematics                     c. Cladistics
                        d. Taxonomy                             e. Trait-branchy Families

                            ...just connects to a definition out of the notes...


                    6. When oxygen built up in Earth's atmosphere, this was not necessarily
                                a good thing because oxygen
                        a. Does not dissolve in water all that well
                        b. Is very chemically reactive and could act as a poison
___B___          c. Would have trapped too much heat in the atmosphere
                        d. Would have blocked important parts of sunlight
                        e. Is an unfriendly molecule with a nasty personality

                            ...out of the notes;  A is true but doesn't answer the question


                    7. Which term goes with the idea that life on Earth acts like a kind of
                                 planet-wide "thermostat"?
___A___          a. Gaia Hypothesis                             b. Endosymbiont theory
                        c. Heterotroph hypothesis                   d. Biosphere theory
                                    e. As long as nobody finds the controls...

                            ...out of the notes (you need to know B and C, too)


                    8. The first "living" molecule systems, in order to be considered as very
                                simple life, had to be able to
___C__          a. Eat & move             b. Reproduce & move            c. Reproduce & evolve
                        d. Breathe & reproduce            e. Sign up and get a membership card

                            ...the only way that they could go on to be life as we know it...


                    9. A group of organisms that can live as independent individuals but are
   
                             usually found together, with different individuals in the group doing
                                different jobs:
___D___          a. Endosymbionts                 b. Prokaryotes                 c. Eukaryotes
                        d. Colony                                             e. Boy bands

                            ...a definition from the notes...


SHORT ANSWER. 

Answer any five of the following questions for 8 Points Each.
Note:
if you answer more than five, only the first five will be corrected.
You can get partial credit on these answers.

1. Photosynthesis might have started at deep-sea hot vents as a mutational combining of which two abilities?

Chemosynthesis
Light sensing / detection

2. What are two different types of energy that could have contributed to the beginnings of Life on the early Earth?  There are more than 2 good candidates...

Hot chemicals
Lightning
Sunlight, especially Ultraviolet


3. What two sorts of environments were probably ideal "staging areas" for the movement of life from water onto the land?

Tidal Pools
Shallow fresh water


4. Briefly explain why disease is a very unlikely cause of mass extinctions.

            ...diseases rarely (pretty much never) hit many forms of life at once, and, more importantly, diseases evolve quickly not to kill off their hosts...


5. Name a eukaryote cell feature that is thought to have originally been an independent organism that was taken in and "put to work."

            ...could be mitochondrion or chloroplast, even flagella...


6. When a biologist has a disagreement about a group's classification -

What are they allowed to try to change?

            ...the group level (move it up or down the "ladder")
What are they NOT easily allowed to change?

            ...the accepted name of the group


7. The earliest living molecule systems are thought to have been mostly one of three different types of molecules. What are two of those molecule types?

Protein
RNA
DNA


8. Suggest two ways that a molecule could out-compete another molecule.

Many ways:
Could access materials faster
Could block access to competitors

Could reproduce itself faster or more efficiently
Could break down competitors
Could "cooperate" with other molecules


9. Put them in order, SMALLEST TO LARGEST: Class, Family, Genus, Kingdom, Order, Phylum, Species, Superclass.

1  Species 2  Genus 3  Family 4  Order
5  Class 6  Superclass 7  Phylum 8  Kingdom


10. The heterotroph hypothesis replaced what difficult-to-explain idea, based on the current world's ecosystem?

            ...it was thought that Life would have had to arisen first with photosynthetic fuel makers, or else what was there to eat?  But explaining a quick development of such a complicated system was almost impossible...

LONG ANSWER.

Answer any three of the following questions for Eleven Points Each.
Note:
if you answer more than three, only the first three will be corrected.
You can get partial credit on these answers.

1. For four of the Five Kingdoms of Living Things, give the proper name of that Kingdom and those traits that set that Kingdom's members clearly apart from the other four.

a.  MONERA
All you need here is that cells have no nuclei.
b.  PROTISTA
Cells have nuclei, but that's not enough (also true for c,d,e);  also needs: group is mostly single-celled forms
c.  FUNGI
Multicelled (a & b have similar single-celled forms);  Heterotrophic, non-moving, absorb nutrients through outside surfaces
d.  PLANTAE
Photosynthetic (not enough - also true in a & b) and multi-celled
e.  ANIMALIA Multicelled, heterotrophic; consume and digest food internally;  usually can move


2. What are four likely events that could have lead to mass extinctions?

Asteroid or comet impacts Ice ages
Major volcanic eruptions Continental drift connecting land masses
Disease is unlikely Major climate changes


3.For the currently-accepted hypothesis for the Origins of Life on Earth, put the following in order (number them) from earliest to latest.

4    Aerobic 
respiration.
6    Multicellular
forms.
1    Chemical 
evolution.
3    Autotrophs.
5    Eukaryotic
cells.
8    Life on
Land.
7    Cambrian
Explosion.
2    Protocells.

After the Earth and Primordial Soup formed,  chemical evolution is leading to first "living" molecules, before cells, and leads to protocells, which aren't even prokaryotes yet.  Once prokaryote cells had evolved, autotrophs and aerobic respiration evolved before the evolution of eukaryote cells, which were necessary before you could have multicelled forms.  The Cambrian Explosion happened while Life was still stuck in the oceans, and much later did Life move out onto land.


4. Name four major groups of living things that are considered "land groups."

Plants
Dinosaurs
Amphibians
Reptiles
Insects
Arachnids
Birds
Mammals


5. Briefly describe (more than 1-2 words, please) four features of living on land that were significantly challenging to water organisms evolving in that direction.

There are more than 4:   Drying Out.
                                     Support (holding oneself up without water bouyancy)
Temperature fluctuations
Direct sunlight
High oxygen levels
Reproduction - having sperm that use water to reach egg cells


NO KEY FOR BONUS QUESTIONS.

BONUS QUESTIONS. 

Answer as many as you are able. Wrong answers will not result in points being lost from the main exam. You can get partial credit on these answers.

Carolus Linnaeus was the "father" of our biology classification system. What was his actual first name? Three Points.




There is a theory that the first "living" systems could have been a type of clay. For Two Points each, what features or abilities of this type of clay make it possible that this is true?




We have some pretty significant, very early fossils locally. What sorts of fossils are they (Three Points), and where are they locally (Three Points)?




When oxygen built up in the atmosphere, what major evidence did it leave in the fossil layers formed at that time? Three Points.




The symbiont "buddies" that accompanied plants onto land - what necessary service did they provide the plants? Three Points.




The big flying and swimming animals that lived with the dinosaurs were not themselves dinosaurs - what group are they classified in? Three Points.




Why is it highly unlikely that any type of whale or penguin would evolve to a form that could breathe water? Three Points.


 
     

 

 

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