AP BIOLOGY
Supplemental Assignment
Mrs. Isengard-Westside High School
This guide is used to review Atoms & Molecules, and Ecology. These are two units that are covered in your
prerequisite Biology and Chemistry courses. Please use:
Chapters 2& 3 for Atoms & Molecules
Chapters 50-56 for Ecology & Animal Behavior
You may use your textbook and any online resources (please cite any you use) to answer the following
questions. This assignment will be due the first day of school and the information will appear in a test that
month. No LATE Assignments will be accepted
Answer the following questions in as much detail as possible and print out to turn in to me. This can be typed
or written but must be legible. I will not accept email submissions for this assignment:
Name-_______________________________
Summer Assignment
1) “Life” is easy to recognize but difficult to define. The dictionary defines life as “the state or quality that
distinguishes living beings or organisms from dead ones and from inorganic matter, characterized
chiefly by metabolism, growth, and the ability to reproduce and respond to stimuli.” Biology textbooks
usually elaborate slightly; for example, according to a popular text, living things:
a. Are highly organized compared to natural inanimate objects.
b. Display homeostasis, maintaining a relatively constant internal environment.
c. Reproduce themselves.
d. Grow and develop from simple beginnings.
e. Take energy and matter from the environment and transform it.
f. Respond to stimuli.
g. Show adaptation to their environment.
Score yourself, a car, and a cactus with respect to these characteristics. Is there any grey area? In the context of
what you just did, why could defining life be an elusive business?
A human would display all of these characteristics for the characteristics of life. A cactus would also
demonstrate these characteristics.
However,the car demonstrates e. and f. as it is responsive to changes and transforms chemical energy into
mechanical energy (gasoline converts into movement through internal combustion). Therefore there are some
grey areas in defining life. One primary example includes viruses; they are capable of reproduction but can’t
live independently requiring a host cell. Another example of an elusive organism is the amoeba which
amorphous and definitely not organized.
2) In 1944, at the beginning of the book, What is Life, the great physicist Erwin Schrödinger (of cat fame)
asked the following question: “How can the events in time and space which take place within the spatial
boundary of a living organism be accounted for by physics and chemistry?” What would be your
answer today? Do you think there are peculiar properties of living systems that disobey the laws of
physics and chemistry? Explain your answer.
There are some close connections between all sciences especially physics and chemistry. For
example, organisms are controlled by metabolism; a sum of all chemical reactions in the body. Aerobic
organisms also have elemental dependencies requiring atmospheric constants for respiration (partial
percentage of gases, and physical parameters including STP (Standard Temperature and Pressure)
volumes and pressure ratios). Conservation of matter and energy is also an important parameter in this
process.
Without these environmental factors, they cannot maintain homeostasis. Also, physical &
chemical properties can be accounted for with heat transfer, movement, growth. Some exceptions to this
rule may include viroids and prions that replicate and thus may not maintain the same conservation of
matter and energy.
It seems to be human nature to try and group living things into categories. These groupings have helped
philosophers and naturalists better understand the living world around them. A taxon is the name given
to any specific level of organization in our current classification system. Identify the taxonomic levels
that biologists most frequently use. How are they organized? Can taxonomic systems be used to show
phylogeny (aka evolutionary relationships) of organisms?
Biologists still categorize taxa in the following from most general to most specific: Domains,
Kingdoms, Phyla, Class, Order, Family, Genus & Species. These taxa are derived from common
characteristics and qualifiers. For example for the case of
Aristotle was one of the first to classify organisms into separate taxa or categories. However,
many of these criteria were based on physical characteristics that failed to show any true evolutionary
commonalities. For examples, Aristotle grouped butterflies and birds together as they are both take
flight. However, we now know based on other characteristics (in the case of butterflies -chitinous wings,
or in the case of a vertebrate bird possessing a yolk sac/amniotic/chorionic tissue that these are two
distinct categories).
3) Chapter 1 includes heredity (i.e. DNA and genes) as well as evolution. Discuss the connection between
heredity and evolution? There is a strong trend between Evolution and Heredity in that Natural
Selection seems to drive inheritance in populations. For example, a microevolution scenario includes
Kettlewell’s Peppered Moths; a study conducted before and following Industrial Revolution. As
pollution increased, the lighter moths were selected against as they could no longer blend in with the
graying lichen on trees. Consequently, these moths were selected against and therefore the selection
curve median shifted towards the darker moths. Many geneticists have determined correlation in
populations and have developed models. One main model is known as Hardy-Weinberg Equilibrium
Principle. If there is no evolution there should be no fluctuation of dominant and recessive individuals in
a population with a baseline 1:1 ratio. If there is a change in these genotypic frequencies, this reveals
evolution.
4) What is meant by the term “descent with modification?” Descent with modification determines a change
in a population indicating evolution. This is often an adaptive change that occurs in offspring which
typically favors those members. In other words, the descendants are modified to best adapt to their
environment.
5) Science is often described to work by a set of steps or by a specific method. Why is this not necessarily
true? Science is constantly occurring and there are many theories that are not tested or can’t be proven
through scientific method.
6) What is the difference between a hypothesis and a theory? A hypothesis is a guess based on observations
and environmental phenomena. A theory is a proposal based from a hypothesis tested multiple times.
However, a theory is still not as concrete as a scientific law because there have been exceptions. Some
examples include the Theory of Evolution, Gene Theory and the Endosymbiotic Theory. Very few
scientific laws exist and often are within the physics field (Laws of Gravity, Inertia, Thermodynamics).
7) What is the arrangement of protons, neutrons and, electrons in an atom? Describe this verbally then
diagrammatically. Positively charged protons and neutrally charged neutrons are found within the
nucleus of the shell providing an overall positive charge to internal atom. Negatively or oppositely
charged subatomic particles known as electrons are found in shells that constantly orbit the outer layer
of the atom.
8) A carbon atom contains six protons and six neutrons.
a. Without looking at a periodic table what is carbons atomic number and atomic weight? How did
you know this? 6; 12 The proton # denotes the atomic # while the mass number is the sum of
protons and neutrons.
b. How many electrons does it have? How many valence electrons does it have? How did you
know this? The C atom would have 6 electrons with 4 valence electrons. Carbon is in the 4th
group which indicates the # of valence electrons.
c. How many additional electrons must it add to fill its outermost shell? 4
d. How does this affect carbon’s chemical behavior? Carbon is tetravalent (forming 4 bonds and
thus serves as the backbone of organic compounds).
e. Carbon with an atomic weight of 14 is radioactive. How does it differ in structure from
nonradioactive carbon? How does this difference affect its chemical behavior? Carbon 14
isotope is structurally different because it possesses two additional electrons. It is chemically
unstable and emits radioactive particles for this purpose.
9) Sketch the electron shell configuration of a sodium atom. According to the octet rule, what would be the
simplest way for a sodium atom to achieve electron stability? Because sodium only has one valence
electron, the simplest way for sodium to achieve is to bond with a halogen possessing 7 valence
electrons. One common exam
10) Many elements have isotopes, which are rare variants of the element with additional neutrons in the
nucleus. Deuterium is an isotope of hydrogen that has one neutron. Does the neutron change the
chemical reactivity of deuterium, compared with normal hydrogen? Explain why or why not.
Generally, the amount of neutrons determines its chemical stability. However, in the case of deuterium,
the isotope remains stable because there is a negligible mass difference between protons and neutrons.
11) The concepts of chemical bonding and electronegativity allow us to predict whether a molecule will be
polar or nonpolar, and how it will interact with water. Typically, a difference in electronegativity
greater than 0.5 will result in polarity. For each of the bonds below indicate:
a) Whether the bond is polar or nonpolar
b) If polar which end is + end
c) How a molecule with the bond will interact with water (hydrophilic or hydrophobic).
N-H Polar
C-H Nonpolar
C=O Polar
C-N (Polar)
Hydrophobic
(+Hydrogen)Hydrophilic
(+Carbon)
(+Nitrogen)
Hydrophilic
H-H Nonpolar
O-P (Polar)
O-H Polar (+Hydrogen) C-C Nonpolar
Hydrophobic
Hydrophobic
Hydrophilic
(+Oxygen)
Hydrophilic
12) Compare electron behavior in ionic, covalent, and hydrogen bonds. Which is strongest, and why? Ionic
bonds have the strongest electron bonds because they have the greatest electronegativity.
13) What is the difference between a covalent and a non-covalent bond? Covalent bonds equally share
electrons while the non-covalent bonds do not.
14) Hydrogen bonds and van der Waals attractions are important in the interactions between molecules in
biology.
a. Describe the differences and similarities between van der Waals attractions and hydrogen bonds.
Van der Waals and Hydrogen Bonds both occur between hydrogen atoms. However, Van der
Waals are more temporary reactions forming and breaking continuously. Van Der Waals are
often found between DNA molecular bonds.
b. Which of the two types of interactions would form (1) between two hydrogens bound to carbon
atoms, (2) between a nitrogen atom and a hydrogen bound to a carbon atom, and (3) between a
nitrogen atom and a hydrogen bound to an oxygen atom?
1) This would form a hydrocarbon non polar bond (often found in lipids)
2) N-H-C would form a non polar bond
3) Nitrogen, hydrogen and oxygen would form a polar bond.
15) How do variations in electronegativity result in the unequal sharing of electrons in polar molecules?
Since electronegativity levels vary, this often causes dipole or various intermolecular reactions causing a
partial positive or negative charge.
16) Consider the molecule carbon dioxide. Are the bonds between the C and the O atoms ionic or covalent?
Is this molecule hydrophobic or hydrophilic? Explain your answers. Bonds between C and O are
covalent because their electronegativity is less than in a hydrophilic molecule.
17) Here is the structure of the molecule glycine:
a) Is this molecule hydrophilic or hydrophobic? Amino acid charges vary/ are hydrophilic or
hydrophobic resulting from whether hydrogen bonds occur. In the case of glycine it is hydrophobic and
does not have a side chain or charge indicating which bond it can form.
b) Draw two glycine molecules and show how they can be linked by dehydration synthesis.
Amino Acids are formed with Peptide Bonds (Between
Amine Groups)
18) What is the difference between a solute and a solvent? Solutes are solid particles that are dissolved into a
solvent (liquid). A good example would be iced tea powder (solute) stirred into a pitcher of water
(solvent). Combined, these form the solution.
19) What is meant by the terms osmosis and diffusion? Are they the same thing? How are they related to
the concepts or hypertonic, isotonic, and hypotonic? Osmosis refers to the diffusion of water down its
concentration gradient. Diffusion refers to any particles moving from an area of high concentration to
low concentration. Hypertonic solutions contain more solute than their surrounding environment,
isotonic solutions are in equilibrium with their environment and hypotonic cells would contain less
solute than their environment. A good example includes mass changes with a grape placed in a
Hypertonic (concentrated salt) solution, -Grape Shrivels
Isotonic (limited salt tap water solution) Grape’s mass remains constant
Hypotonic (deionized, tap water solution). Grape takes in water (increases mass)
20) Transpiration is the name given to how water travels up a plant, from its roots to its leaves. Discuss how
this happens in the context of waters special properties.
Transpiration involves the uptake of water through xylem canals. This applies two important water
properties, including adhesion (water connecting to the sides of plant or another surface). The second
main property is cohesion where water molecules stick to one another and draw each other up the plant.
21) The organic chemistry of living cells is said to be special for two reasons: it occurs in an aqueous
environment and it accomplishes some very complex reactions. But do you suppose it’s really all that
much different from the organic chemistry carried out in the top laboratories in the world? Why or why
not?
I don’t believe so. Dehydration synthesis & condensation reactions are occurring in the environment all
the time. However, top labs will use pre-existing organic compounds to synthesize new synthetic
compounds from these base reactions.
22) What is pH? What does the pH scale represent? How do you calculate pH?
pH is a logarithm of hydrogen protons found in a given solution. The pH scale represents the ratio of
hydroxide (OH ions) and (H protons) found in a substance to base 10. You can calculate pH in a number
of ways; by subtracting the hydrogen protons from 1x 10 -14 this will provide the approximate
concentration of H protons thus giving you pH.
23) Why is pH important to the functioning of biological systems? pH is an essential part of most systems
because it provides a buffer for chemical reactions. For example, human blood is alkaline must not vary
much outside of 7.4. Anything lower or higher than that number can cause enzymatic failure, illness and
even death.
24) How are two monomers linked together? Broken down? P. 50 Monomers are linked with a
condensation reaction (removing a water molecule to form a polymer).
They are broken down through (hydrolysis) reactions that release water into the environment.
25) Draw the chemical structure of a disaccharide formed by two glucose monosaccharides.
26) Examine the glucose molecule shown in your textbook. Identify the functional groups on the molecule.
Glucose (a hexose sugar-monosaccharide) is collectively known as an aldehyde possessing a double
bond between C & O. It also holds a hydroxyl (-OH group).
27) What are the structural differences between alpha-glucose and beta-glucose? How does this difference
affect the structure of a string of alpha-glucose molecules in comparison to a string of beta- glucose
molecules? Explain why this happens. Alpha and Beta glucose are two differences in monomer
structure based on the location of –OH or hydroxyl group relative to the side chain. If OH is on the same
side it is known as a Beta glucose; it is an alpha Glucose if on opposing ends.
28) Some sugars have other functional groups in addition to those typically present. Draw the structure of
the amino sugar glucosamine, which has an amino group bonded at carbon #2 of glucose. Would this
molecule be more or less polar than glucose? Explain why.
This polymer would be less polar than glucose based on its new electronegativity associated with the
additional amine group (NH2).
29) The molecular formula for glucose is C6H12O6. What would be the molecular formula for a
polysaccharide made by linking ten glucose molecules together by dehydration reactions? Initially you
would multiply each compound by 10 giving you 60 Carbons, 120 Hydrogens, and 60 Oxygens.
However, you would need to remove 9 H20 molecules to link the compound together. This results in
subtracting 18 Hydrogen (9x 2= 18) and 9 Oxygen molecules to form the polysaccharide. This would
give you C60H102O51
30) What is the difference between fats and oils?
Fats are solids, but may liquefy at room temperature. This is solidity is based on saturation levels as
most fats have very few available unbonded carbons. Oils are always liquid-based at room temperature.
31) Why are phospholipids amphipathic, and how does this result in a lipid bilayer membrane? Since
phospholipids have differing polarities on opposing sides of the molecule, this renders the lipid bilayer
selectively permeable. This allows the membrane to filter or channel proteins, toxins and other
molecules based on polarity.
32) If fatty acids are carefully put onto the surface of water, they will form a single molecular layer. If the
mixture is then shaken vigorously, the fatty acids will form round structures called micelles. Why does
this happen? Explain. Micelles form as a way to gather nonpolar molecules in a spherical form. This
same process allows us to extract DNA (a polar molecule) with liquid detergent (nonpolar substance).
33) List the key differences between DNA and RNA and between purines and pyrimidines.DNA is double
ringed whereas RNA is single ringed. Both molecules include purines and pyrimidines just in different
chemical forms.
34) How can DNA molecules be so diverse when they appear to be structurally similar? The unique nitrogen
bonding sequence is what produces genetic diversity. One nitrogenous base substitution could produce a
completely different amino acid sequence and thus an entirely different protein. This is why polygenic
traits are so diverse such as eye color and hair color.
35) What attributes of an amino acid’s R group would make it hydrophobic? Hydrophilic? Nonpolar amino
acids have hydrophobic side chains which often include hydrocarbons. This is also why lipids are
considered nonpolar.
Polar amino acids would have hydrophilic side chains. If there are OH groups (basic amino acids) these
would be hydrophilic. Carboxyl groups are electrically charged and are also therefore polar.
36) Sketch the bonding of two amino acids, glycine and leucine, by a peptide linkage. Now add a third
amino acid, alanine, in the position it would have if added within a biological system. What is the
directionality of this process? D- Directionality because it moves in a clockwise fashion from (CORN)Carboxyl, R-group, Nitrogen Group). L Directionality would imply there was a counter clockwise
rotation from the alpha carbon.
Does it grow from the N-terminus out or the C-terminus out? Molecule should grow from the CTerminus out because they are building on the right-hand side.
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=BIC007
The following questions have some notes with it. Please read through it.
37) What was the first 1° structure of a protein to be determined, and how was it done?
chain was analyzed with primer analysis that indicated amino acid sequence.
A polypeptide
A similar technique based on the overlapping segments is also used to sequence DNA nucleotides which
is called “Chromosome Walking”.
The structure of a protein is so important that changing just one amino acid in a chain of over 100 can
cause a deadly disease.
2° Structure: In many cases you will see a helix or b pleated sheets. Your textbook doesn’t put the b in
front of the pleated sheets, but many references do. The a and b are just there because the helix structure was
discovered first.
38) Which is a stronger structure, an a helix or b pleated sheets. Explain your answer. P.65 Disulfide
bridges are found between beta pleated sheets and are therefore recognized as being stronger whereas
alpha helices provide flexibility for hair, nails, spider webs.
Disulfide bridges do not just form spontaneously. Note that there is an H attached to the S in Cysteine.
Thus a group of enzymes known as Protein Disulfide Isomerases (PDI’s) must catalyze the reaction by
removing the H’s in order for the S-S covalent bonds to form. Disulfide bridges can occur in both 3° and 4°
structures. The process is still unknown and it is under investigation because it is very hard to study.
4° Structure: Please note that just because the most commonly used example is hemoglobin with 4
subunits (2 a and 2 b chains), the 4° structure IS NOT the way that 4 polypeptide chains are put together.
According to a reader for the AP exam essays, that was a commonly misused example in the 2001 exam Essay
#4 part (a).
39) What is denaturation, and how can it occur? You must be able to explain not just the what’s (i.e. temp),
but the how’s (how does temperature effect the structure).
Denaturation alters an enzyme’s molecular conformation so that it can no longer bond with the substrate at the
appropriate enzyme-substrate complex. Consequently, temperature, pH and environmental factors often affect
the ability for enzymatic reactions to occur. Childhood fevers are of particular concern for this reason as they
can severely affect enzymatic rate.
40) Detergents disrupt hydrophobic interactions by coating hydrophobic molecules with a molecule that has
a hydrophilic surface. When hemoglobin is treated with a detergent, the four polypeptide chains
separate and become random coils. Explain these observations. The four polypeptide chains form a
quarternary structure in a hemoglobin molecule. This globular structure is what provides hemoglobin
stability to carry oxygen through the bloodstream. Detergent would break bonds between these once
nonpolar/hydrophobic molecules by disrupting the charges from coating with hydrophilic markers.
41) The amino acid lysine is at the active site of an enzyme. Normally the enzyme is active at pH 7. At pH
5, the enzyme is inactive. Explain these observations.
pH is an environmental factor that adversely affects enzymatic function. Thus a pH of 5 would be far too
acidic for the chemical reaction to occur anymore and would affect conformation of the active site.
42) Biological systems contain “supermolecular complexes,” which are composed of individual molecules
of RNA and protein that fit together noncovalently. These complexes can be split apart with detergents
that disrupt hydrophobic interactions. Based on your knowledge, fill in the table at the right to indicate
which of the observations are characteristic of RNA, which are characteristics of proteins, and which are
characteristics of both. Explain your answers.
Observation
Protein
RNA
Has three-dimensional
X
X
structure
Monomers connected by N-C
bonds
3D structure destroyed by heat
Contains sulfur atoms
Contains phosphorus atoms
X
X
X
43) Fill out the following chart:
Primarily used for
Carbohydrate
Energy
Lipid
Insulation
Protein
Building Blocks of
Life
Store Genetic Info
Nucleic Acid
X
Examples include
Bonds made to form
polymers
Glucose, Cellulose,
Glycogen
Hydrocarbons,
Triglycerides,
Cholesterols, Steroids
Amino Acids
Dehydration / Polar
Bonds
Ester Linkages
RNA & DNA
Hydrogen Bonds/Van
Der Waals
Interactions
Peptide Bonds
ECOLOGY
1. List the 5 levels of ecological study and give examples of the focus of inquiry at each level:
organism, analyzing fertility of one individual dusky gopher frog
population, -monitoring the endangered dusky gopher frog population and monitoring their water
source (only 100 left in the world!).
community, - monitoring interactions between said frogs and caddisfly prey availability.
ecosystem, Determining effects of abiotic factors including precipitation and temperature on frog/fly
communities.
Biosphere A global study comparing related amphibian species of comparable ecosystems.
2. Give an example of a purposefully introduced species and an accidentally introduced species that have
become pests in North America: Zebra mussels represent purposefully introduced species. Wooly
adelgids were accidentally introduced.
3. Mountains affect local climate. Describe their influence in the following three areas:
a. solar radiation: Higher altitudes result in decreased altitude decreasing solar radiation absorbency.
Hence, in mountain ranges, organisms are more susceptible to UV light exposure. This is especially
problematic as the Ozone layer diminishes.
b. temperature: Cooling air from mountains can condense and cool the air below in valleys.
c. rainfall: Transpiration occurs at heavy levels in mountain or cloud forests, this can contribute to the
hydrological cycle.
4. Indicate with a + or – whether the following are relatively high or low in oxygen level, nutrient content
and productivity.
Biome
Oxygen level Nutrient content Productivity
Oligotrophic lake
+
Eutrophic lake
+
+
Headwater of stream +
+
+
Turbid river
Estuary
+
+
+
5. Define ecology: Study of interactions between organisms and their environment.
6. What methods are used to answer ecological questions? Surveying, population counts (demographics),
catch & release programs, nutrient measurements, carrying capacity, land monitoring.
7. What are biomes? Regional ecosystems and their organisms ex) Tundra, Desert, Taiga
8. What accounts for the similarities in life forms found in the same type of biome in geographically
separated areas? Climatic similarities often account for similar adaptations; Subequatorial Africa &
Tropical Rainforests of Brazil both have prosimians (lemurs, or tarsier with large eyes to allow for light.
Also, bright coloring or plumage is prominent since this camouflages them better than drab coloring as
in deserts.
9. Many animals breed in the spring and early summer. What is a probable proximate cause of this
behavior? Availability of nutrients and resources for additional reproductive energy. Probable ultimate
cause? Temperate environment and time for growth before cold season.
10. What is the sign stimulus for attack behavior in male stickleback fish? Males are triggered by anything
red and will accordingly display a threat against a perceived aggressor.
11. Give an example of a FAP in a human infant and the sign stimulus that elicits it. Fixed Action Pattern
would be the sucking motion in infants if their cheek is touched; implying nursing.
12. Explain how Zack’s study of whelk-eating crow supports the optimal foraging theory. Optimal foraging
implies organisms will expend the least amount of energy to obtain the most optimal amount of food. In
this case, Zach noticed that crows would consistently drop larger welks from approximately 5 meters to
gain the maximum nutrients.
13. Indicate the type of learning illustrated by the following examples:
a. Ewes will adopt and nurse a lamb shortly after they five birth to their own lamb but will butt and
reject a lamb introduced a day or two later. Motor Behavior p. 1104 (FAP-Fixed Action Pattern).
b. A dog, whose early “accidents” were cleaned up with paper towels accompanied with harsh
discipline, hides under the bed any time a paper towel is used in the house. Operant Conditioning
c. Ducklings eventually ignore a cardboard silhouette of a hawk that is repeatedly flown over them.
Habituation
d. Kittens stalk and pounce on each other, biting and kicking as they roll around together. Innate
Behavior/ Instinct
e. In Pavlov’s experiments, the ringing of a bell caused a dog to salivate. Classical Conditioning
14. Sow bugs are placed in experimental chambers that are either humid or dry and have both light and dark
areas. In the humid chamber, the sow bugs move into the dark area and stop moving. In the dry
chamber, they move into the dark area and continue to move about in that area. Explain these
experimental results. Sow Bugs may be conditioned to conserve energy and prevent dehydration.
Therefore, they are more active in the drier environment.
15. Why are many interactions between members of the same species agonistic? Principles of Natural
Selection imply that only the strongest members survive. Therefore there’s constant competition for
resources allowing the “fittest” members to produce offspring.
16. What mechanisms reduce violent encounters between members of the same social group? Overall fitness
of the group- continuing genes
17. Explain the basis for the distinction between male competition and female choice in courtship behavior.
 Male competition might include physical features such as antler size in Whitetail Deer. (How
well he can fend off other male competitors).

Female Choice can depend on the male’s ability to obtain resources. Many female bird species
seek males with bright plumage implying strong foraging ability.
 Courtship Behavior is an interaction between both genders but pertains more to a one-to-one
relationship. For fruit flies or Drosophila melanogaster, this involves tapping and wing vibration
for gender identification.
18. Natural selection has resulted in exclusive male and parental care being much more frequent in species
with external fertilization, where the male’s genetic contribution to the offspring is more
certain. Explain how such behavior could evolve.
According to Hamilton’s rule, males are more invested in offspring with which they share relatedness.
19. Why is most communication among mammals olfactory and auditory, whereas communication among
birds is visual and auditory? Mammals have smell and communicate through pheromones. Hearing is
also a keener sense as vocalization is common. Since birds do not possess olfactory traits, hearing &
vision are chief communication methods. For example, plumage is also a visual communicative factor.
Birds possess a syrinx which is sensitive to tune changes and therefore auditory signals are generally
used.
20. According to kin selection, would an individual be more likely to exhibit altruistic behavior toward a
parent, a sibling, or a first cousin? Explain your answer in terms of r in Hamilton’s rule. According to
this rule, a sibling would have the most altruistic behavior based on their (r) relatedness of 0.5. While a
cousin’s relatedness would be only (0.25). Also, because their siblings will likely outlive their parents,
they have this additional genetic investment.
where
r = the genetic relatedness of the recipient to the actor, often defined as the probability that a gene
picked randomly from each at the same locus is identical by descent.
B = the additional reproductive benefit gained by the recipient of the altruistic act,
C = the reproductive cost to the individual performing the act.
21. How does the nature vs. nurture controversy apply to behavior?
Nature implies that genetic factors drive evolution. A good example would be that naturally can
camouflage blending into their surroundings.
However, nurture implies that learned behaviors are more evolutionarily successful. For example, male
lizards patrol at the height of reproductive season thus increases mating probability while minimizing
energy costs.
22. How does this concept of Darwinian fitness apply to behavior? “Fitness” is measured an organism’s
ability to reproduce the highest amount of offspring. Therefore, those that survivability is directly
correlated to fitness and offspring behave accordingly.
23. In a mark-recapture study, an ecologist traps, marks and releases 25 voles in a small wooded area. A
week later she resets her traps and captures 30 voles, 10 of which were marked. What is her estimate of
the population of voles in the area?
According to the Lincoln-Peterson method, one can calculate total populations
N= (25X30) = 750
10
10 = 75 total estimated populations.
where
N = Estimate of total population size = unknown
M = Total number of animals captured and marked on the first visit= 25
C = Total number of animals captured on the second visit 30
R = Number of animals captured on the first visit that were then recaptured on the second visit 10
24. Identify the types of survivorship curves shown below and give examples of groups that exhibit each
curve.

A. Type I survivorship curves are characterized by high survival in early and middle life, followed by a
rapid decline in survivorship in later life. Humans are one of the species that show this pattern of
survivorship.

B. Type II curves are an intermediate between Type I and III, where roughly constant mortality rate is
experienced regardless of age. Some birds follow this pattern of survival.

C. In Type III curves, the greatest mortality is experienced early on in life, with relatively low rates of
death for those surviving this bottleneck. This type of curve is characteristic of species that produce a
large number of offspring (see r/K selection theory). One example of a species that follows this type of
survivorship curve is the Octopus.
25. Mortality, number of offspring per reproduction, and prenatal investment are usually interrelated. On
the following graphs, sketch the relationship you would predict between the variables.
26. Label the exponential (a) and logistic (b) growth curves, and show the equation associated with each
curve. What is K for the population show with curve b?
27. List some density-dependent factors that may limit population growth Resource availability i.e. living
space, food, cover, water, minerals & sunlight p. 1132).
28. List some abiotic factors that may cause population fluctuations. Weather, Water availability, soil
quality,
29. Species composition and distribution in most plant communities appear to be individualistic. What may
explain the occasional occurrence of sharp delineations in species composition between communities?
Adaptive strategies & resource availability could make a difference; soil composition, sunlight exposure,
leaf/stomatal ratios and herbivorous members can control height, canopy covering and plant structure.
30. Name the following 2 types of mimicry:
a. Harmless species resembling a poisonous or distasteful species: Batesian Mimicry (Coral Snake
and Scarlet King Snake are examples) p. 1155
b. Mutual imitation by two or more distasteful species: Mullerian Mimicry between monarch and
viceroy butterfly.
31. Name and give examples of the interspecific interactions symbolized in the table:
Interactions
Examples p. 1156
+/+
Mutualism
Mycorrhizae and plant species provide minerals
and nourishment to soil
+/0
Commensalism Silver Fish sharing ant communities
+/-
Parasitism
Flukes in a host organism; Tapeworms; Viruses
(Bacteriophages)
-/-
Interspecific
Competition
Weeds competing with existing lawn grass for soil
nutrients
32. Experimental data from tree hole communities showed that food chains were longest when food supply
at the producer level was greatest. Which hypothesis about what limits food chain length do these
results support? Energetic Hypothesis
33. Many freshwater lake communities appear to be organized along the top-down model. What actions
might ecologists take if they wanted to use biomanipulation to control excessive algae blooms in a lake
with four trophic levels (algae, zooplankton, primary predator fish, and top predator fish)?
Increase the amount of top predator fish which would reduce primary predatory fish thus increasing
zooplankton who can feed on algae reducing algal blooms.
34. Describe the effects of the alder stage of succession on soil pH and fertility. The alder stage contains
nitrogen fixing compounds which would modify soil pH. Rather than the typically expected alkaline
(basic soil, these compounds encourage further growth).
35. List some ecosystems with high rates of production. Tropical Rainforest, Deciduous Forest, Wetlands
36. List some ecosystems with low rates of production. Desert, Tundra, Taiga
37. The open ocean has low net primary production yet contributes the greatest percentage of earth’s net
primary production. Explain. Light availability, surface area and the high diversity of photosynthesizing
algae contributes to the primary production. Net productivity= Gross Productivity-Oxygen Production
38. Antarctic seas are often more productive than most tropical seas, even though they are colder and
receive lower light intensity. Explain. Because of the water’s insulating properties, ice maintains
thermoregulation. Antarctic seas have microbiota and algal organisms that have a unique ecological
niche.
39. Why is production efficiency higher for fishes than for birds and mammals? Because fishes aren’t
responsible for aerobic respiration and terrestrial metabolic requirements they don’t expend as much
energy in water.
40. Assuming a 10% trophic efficiency (transfer of energy to the next tropic level), approximately what
proportion of the chemical energy produced in photosynthesis makes it to a tertiary consumer? 0.1%
41. In which natural ecosystem do nutrients cycle the fastest? Why? Tropical Rainforest. Because of high
precipitation rates, soil doesn’t retain nutritive value very long so this must quickly be recycled.
42. In which natural ecosystem to nutrients cycle the slowest? Why? Tundras cycle the slowest because of
dormancy rates and slow microbial rates in soil decomposition. Oceans also cycle slowly (marine
habitats cycle the largest amount of nitrogen and other chemical compounds).
43. What is the effect of loss of vegetation on nutrient cycling? Vegetation can remove vital nutrients from
the cycle and can also reduce the amount of nitrogen fixation as decomposition rates dwindle.
44. List some of the potential consequences of global warming: Global warming causes oceanic
temperatures to rise (although seemingly negligible a 1-3 degree increase can severely affect primary
productivity, natural phenomena (like hurricanes) are closely correlated to global warming).
45. Two processes that emerge at the ecosystem level of organization are energy flow and chemical
cycling. Develop a concept map that explains, compares, and contrasts these 2 processes.
46. Describe four or five human intrusions in ecosystem dynamics that have detrimental effects. Habitat
Encroachment, Introduced Species, Monoculture (Lawns vs. Meadows; Deforestation), Residential
Development, Burning Fossil Fuels.
47. Give an example of how each of the following causes of the biodiversity crisis has reduced population
numbers or caused extinctions.
a.
habitat destruction: Many endangered species (dusky gopher frog) are susceptible to extinction
and are now limited to one pond in Mississippi.
b. introduced species: Zebra Mollusks have no natural predators and now clog boat motors and
leading to destruction of habitat.
c.
overexploitation Deforestation has rendered the tropical rainforests bereft of many unique
ecological habitats.
d. disruption of food chains: Overcapture or poaching of game fish has caused algal blooms in topdown trophic pyramids.
48. Is the effective population size usually larger or smaller than the actual number of individuals in the
population? Explain. Smaller than the actual number, these are based on conservative estimates.
49. Explain the basic premise of the small population approach. The premise is to bolster genetic diversity
in dwindling or threatened species. What conservation strategy is recommended for preserving small
populations? By grouping several members of the same species for mating ecologists try to increase
population counts.
50. Describe the declining-population approach to the conservation of endangered species. This approach is
used to identify environmental factors contributing (habitat loss, extinction threats).
51. What are some potential benefits of corridors? How may they be harmful? Riparian corridors are used
as a protective avenue however, they can harm species by reducing genetic diversity through geographic
isolation.
52. What factors would favor the creation of larger, extensive preserves? Larger population counts What
factors favor smaller, unconnected preserves? Smaller organisms which close relatedness.
53. What are the major threats to biodiversity, listed in order of importance?
54. How does the loss of biodiversity threaten human welfare? Resource availability, Primary Productivity,
Oxygen Production and Nutrient Cycling are all consequences of biodiversity loss.
55. What do edges and movement corridors have to do with habitat fragmentation? Edges corridors are for
species that avoid perimeters. Marine species actually do very well with this barrier. The area to
perimeter ratio must be kept small to avoid this. Movement corridors are for highly mobile species. By
establishing these fluid corridors, ecologists avoid habitat fragmentation.