Download Summer Assignment Answer Key

Summer Assignment Answer Key 2016-2017
Chapter 1: Introduction: Themes in the Study of Life
Explain in your own words:
1. Eukaryotic cell – larger and more complex than prokaryotic, have a nucleus and membrane
bound organelles. Animal cells are a good example.
2. Prokaryotic Cell – smaller and less complex than eukaryotic, no nucleus, no membrane bound
organelles. Bacterium is a good example.
3. Genes – units of inheritance that transmit information from parents to offspring
4. Genome – the entire library of genetic information that an organism inherits (all the genes
reflected in codes made up of A,T,C and G).
5. Negative feedback - accumulation of an end product of a process slows that process that makes
it. Think of it this way: negative feedback loops lessen the impact of the stimulus. Another way
to say this is that negative loops maintain a “set point”. Our constant body temp is a good
example – hot temp causes us to sweat, sweating keeps our internal temp constant by pulling
excess heat way from our body, thus limiting the impact of the heat stimulus.
6. Positive feedback loop – less common in living things. The end product of a process speeds up
the process. Clotting of your blood, perpetuates more clotting (this is good – you can stop
bleeding)
7. Hypothesis – a useful and testable prediction geared toward answering a question about the
natural world.
8. Controlled experiment- only a single variable is changed and an experimental group is compared
to a control group (the group that did not receive any “treatment”)
9. These should look like the characteristics of life to you!
10. 1. Deoxyribose 2. Nucleotide 3. DNA 4. Gene 5. Chromosome 6. Nucleus 7. Cell 8. Tissue 9.
Organ 10. Organ System 11. Organism 12. Population 13. Community 14. Ecosystem 15.
Biosphere
11. I’m leaving this one up to you as it is straight from the text
12. Biosphere contains the most diversity and population contains the least as the population term
refers to only one type of species.
Chapter 2: The Chemical Context of Life
1-12 – Text definitions I’m leaving to you.
13. Although we know it’s not correct, model b of figure 2.5 on page 33 shows the Bohr model of
the He atom. Note: 2 protons, 2 neutrons and 2 electrons. The electron cloud model (a) is more
correct, but harder to visualize. We can only approximate a region (cloud) in which the electron
can be found and never know its exact location.
14. Atm. # = 2 Atm. Mass = 4
15. Mass = 12 # = 6
16. Valence = 1 (the outer most electron) Protons = 11
17. In nonpolar covalent bonds the electrons are shared evenly between atoms. In polar covalent
bonds one atom is more electronegative then another (influencing electrons toward it),
although electrons are still shared, they are shared unevenly resulting in slightly negative and
positive sides to the molecule. Water is an example of polar covalent bonding.
18. Oxygen is most electronegative (it has the larger nucleus influencing electrons toward it), so
electrons hang out closer to the oxygen atom. Protons left in hydrogen nuclei result in a slightly
positive charge on the hydrogen side.
+
H
H
O
H
19. Electrons are being transferred from one atom to another. The resulting charge imbalance
holds the atoms together. Atoms involved = Na and Cl
20. Anions have net negative charges and cations have net positive charges. Na is the cation and Cl
is the anion.
Light
21. 6CO2 + 6H2O
C6H12O6 + 6O2
Reactants
Products
22. 6 CO2, 1 Glucose, 3 elements (CHO)
Chapter 3: Water and the Fitness of the Environment
1-14. text definitions I will leave to you
15. A molecule that exhibits negative and positively charged sides. Water has a slightly negative
(oxygen) and slightly positive side (hydrogen).
16. Water can absorb a significant amount of heat energy before changing temperature (e.g. oceans are
a heat sink on earth absorbing much of the sun’s solar radiation). Specific heat is the amount of energy
that can be absorbed by 1 g of a substance that causes the substance to change temperature by 1
degree C. Water = 1 calorie/g/deg C Alcohol = 0.6 cal/g/deg C
17. More energy is required to break hydrogen bonds between molecules, in addition to the polar
covalent bonds that hold the molecule together
18. Water helps us maintain homeostasis through sweating. Aquatic organisms rely on water to absorb
heat energy with only moderate changes so they too can maintain homeostasis. Would be the fate of a
fish that needs to deal with water temperatures equal to air temperatures?
19. Coffee = solvent, Sugar = solute (water is the universal solvent!)
20.
a. 100 times (2 units or 10 x 10)
b. 10,000 times (4 units or 10 x10 x 10x10)
c. pH of 8 = 1x10-8 H+ and pH of 12 = 1x10-12 H+, in other words there is 10,000 times more H+ in
a solution of pH 8 than a solution of pH 12.
21. Buffers are not strong acids or strong bases, therefore they can contribute or sequester H+ from
solutions helping to prevent wide fluctuations in pH. The bicarbonate ion HCO3- is the blood buffer
keeping your blood pH at approximately 7.4.
23.
The equation above shows that HCO3- (the buffer) can shift back and forth in your blood. When
the reaction progresses to the right it contributes H+ to solution making blood more acidic. To
the left it sequesters H+ as carbonic acid (H2CO3 – eventually converted to CO2 and expelled
through your lungs), making blood more basic.
Chapter 52: An Introduction to Ecology and the Biosphere
1-8 Text definitions leaving to you
9. Biotic = living Abiotic = nonliving
10. Plants, animals, microbes, fungi, algae
11. rocks, minerals, water, air, soil
12. Biosphere, Ecosystem, Community, Population, Species (individual)
13. Biomes – please consult your text
Chapter 53: Population Ecology
1-9 Text definitions leaving to you
10. Population density – the number of individuals per unit area or volume (e.g. number of oak trees per
square kilometer in Columbia county, Pennsylvania)
11. Estimate based on indexes of population like: droppings, nests, tracks, burrows, etc. Populations can
also be measured by assessing the number of individuals in randomly selected plots of the same size,
then extrapolating to a large area. Lastly, the mark and recapture method is also used.
12. Uniform – individuals are evenly distributed throught their range, could suggest some means to
exclude other species or territoriality between individuals. Clumped – the most common type of
dispersion, animals are situated together around food sources, supports behaviors related to hunting or
mating. Random – occurs in the absence of strong attractions or repulsions among individuals of a
population (e.g. plants established by windblown seeds)
13.
Survival per thousand
1000
Human
(type I)
Hydra
(type II)
100
Oyster
(type III)
10
1
0
25
50
75
100
Percent of maximum life span
Type I - Humans survive at fairly high rates in the early part of their lives and don’t start to experience
increasing mortality until after childbearing years eventually dying off in old age.
Type II – The hydra has a nearly equal chance of survival at younger, middle or older ages. Age does not
play a role in survival.
Type III – Oysters experience very high mortality when young, but if they make it through the first 25%
of their total lifespan they tend to live very long.
14.
15.
Decelerating rate
Accelerating rate
Slow growth
16.
17. Density dependent factors are those that provide negative feedback with regard to population
growth (limiting). Things like disease, competition for resources, predation, habitat, and territoriality all
contribute to limiting the population and density dependent. Density independent factors are those
that could have an impact on the population whether or not the population is large or small. Density
independent limiting factors include things like drought, sunlight, temperature, natural disasters,
chemical changes in the environment.
Chapter 54: Community Ecology
1-15 Text definitions leaving to you
16. An organism’s niche can be thought of as its job within an ecosystem (the role it plays). Where lives
is the habitat that it occupies, but a niche is more than where it lives it really pertains to what that
organism does. The competitive exclusion principle says that no two similar species can occupy the
same niche (have the same job). For instance one of two birds of prey that hunt in the same area, eat
the same foods, hunt at the same time of day, compete for the same nesting sites and possibly similar
mates would eventually die off or move out of that niche because it would have been outcompeted by
the other.
17. and 18. Parasitism - is a +/- interaction between species. Positive for the parasite and negative for
the host. A good example from our area would be deer ticks and whitetail deer.
Predation – is a +/- interaction. It is positive fort the predator and negative for the prey since the prey is
killed.
Mutualism – is a +/+ interaction where both species benefit from the relationship. An example would
be the acacia tree and ants detailed on page 1203 in your text.
Intraspecific competition – is a -/- interaction between members of the same species. Competition
detracts from the fitness of individuals within the population as they are devoting energy and resources
to competing among themselves.
Commensalism – is a +/0 relationship where one species benefits and the other is completely
unaffected. An example would be the barnacle and whale. The whale is not impacted in any way, but
the barnacle is given mobility by the whale and is able to access more food.
19. Ecological succession is constantly occurring whether it be in abandoned fields, after forest fires,
after natural disasters such as earthquakes, landslides, volcanic eruptions, etc. Primary succession
occurs on rock where no soil layer is present. Secondary succession occurs where there is already a soil
layer in place.
Chapter 55: Ecosystems
1-8 Text definitions leaving to you
9. Autotroph – classically say that these organisms make their own food, typically by photosynthesis.
Essentially they convert solar energy into chemical energy (sugar). Phytoplankton, plants, moss/ferns
10. Heterotroph – not capable of making their own food, sometimes called consumers. Convert sugars
into energy molecules like ATP. Animals, fungi, zooplankton
11. Food chains represent the flow of energy linearly between and limited set of organisms. Webs show
energy flow in a more realistic and complex web of interactions.
12. Only 10% of the energy in a lower level is transferred to the energy level above. Most of the energy
lost (90%) is wasted as heat.
13. Detritivore (decomposer) – a consumer that derives its energy and nutrients from nonliving organic
matter such as waste, corpses, decaying plant material.
Dung beetle – rolls animal dung into balls and buries them in the soil to feed their young
Fungi – heterotrophs that live on dead, decaying organic matter (rotting leaves and wood)
Turkey vulture – we see these in Pennsylvania all the time feeding on carcasses along the road and in
fields.
14. Herbivore – a consumer that eats plant material to derive its energy.
Grasshopper, cows, and rabbits – these organisms must be good at digesting cellulose as it is a
polysaccharide that is a main component of plants. We (humans) are not good at digesting plant
material.
15. Omnivore – a consumer that eats both plants and other animals.
Raccoons, rats, bears, gorillas, skunks, mice, humans
16. Carnivore – a consumer that mainly eats other animals
Lions, tigers, wolves, some sharks, crocodiles, owls
17. Gross primary productivity (GPP) – the amount of light energy converted to chemical energy via
photosynthesis.
Net primary productivity (NPP) – equal to the GPP minus the energy used by the producers to conduct
respiration. In other words, the amount of energy left over after respiration and available for
consumers in a food chain or web.
18. Figure 55.4 from your text
19. Pyramids are used because as we know they are shaped like a triangle with the longest side on the
bottom and the remaining two sides narrowing to a point at the top. This relates to productivity
(energy) within the ecosystem because most of the energy available is at the bottom and is comprised of
photosynthetic organisms. As we move up the pyramid through different trophic levels (primary,
secondary and tertiary consumers) the amount of energy available rapidly decreases.
We don’t typically see more than 4 levels in a food chain because there simply isn’t enough energy
available as the chain progresses to support higher order consumers beyond secondary or tertiary
levels.
Only 10% of the energy at one level is available to the level above it. 90% is lost as heat during the
energy transfer from one level to the next. See the figure below.
20. Carbon cycle – carbon is primarily entering the system through atmospheric CO2 and is taken up by
plants. CO2 is leaving through respiration from producers and consumers. Anthropogenic sources of
CO2 are also being contributed to the atmosphere from things like burning fossil fuels. Major reservoirs
are fossil fuels, aquatic sediments, oceans, biomass and sedimentary rocks.
21. Nitrogen cycle – most nitrogen is atmospheric and enters the cycle through nitrogen fixation by
animals and nitrogen fixing bacteria. Microorganisms are fixing the nitrogen and making it available for
uptake by plants. Nitrogen is a major plant nutrient. Denitrifying microorganisms are also converting
NO3- under anaerobic conditions into N2 (atmospheric) and releasing it to the atmosphere.
See pages 1232-1233 in your text for a more detailed explanation of these cycles.