Biology 20 Review – Chapters 1, 2 and 3 1. Study the food web below and fill in the blanks in the questions provided a) The following organisms in the food web are producers: ___algae, wheat, grass____. Producers are also known as ____autotrophs__. b) A __paramecium or minnow_ is an example of an aquatic herbivore in the food

web. A __rabbit or field mouse__ is an example of a terrestrial herbivore. c) Water spiders are classified as __secondary___ consumers and occupy the

___third___ trophic level. d) Field mice are classified as primary____consumers and occupy the ___second_

trophic level. e) The highest trophic level the bass could occupy is the _fifth__trophic level. f) The snake population in this community has been decreasing due to loss of

habitat. As a result, the weasel population will _probably increase(due to increased food supply)_ and the field mouse population will _probably increase (due to less hunting pressure by the weasels, who now have another abundant food supply)_.

algae wheat grass

minnow paramecium rabbit Field mouse

crayfish water spider

snake

weasel

trout

bass wolf

2 a) What kind of ecological pyramid is depicted in the above diagram? _________________________pyramid of numbers____________________________ b) What is the advantage of this type of pyramid? The disadvantage? Advantage: easy to catch and count organisms or estimate their population by sampling Disadvantage: not very accurate measure of actual energy at each trophic level

c) What kind of ecological pyramid is depicted in the above diagram? Why is this a better representation of an ecosystem than the pyramid in question 2a? ______Biomass: takes into account differing sizes of animals and is thus a more accurate description of the energy relationships in an ecosystem.________________________________________________________________

DDT accumulation in a marine food web, in parts per million (ppm)

The arrows show the flow of energy from one trophic level to another. The concentration of DDT increases with each successive energy transfer in the food web. 1 ppm = 1 mg/kg. 3a. The diagram on the previous page shows the biomagnification of DDT as it passes

through a marine food web. Explain what is meant by the term biomagnification. How many times greater is the concentration of DDT at the highest trophic level than at the lowest trophic level?

Biomagnification (or bioaccumulation, or biological amplification) is the increase in the concentration of persistent chemicals (such as pesticides) in ecosystems as they pass up the levels of a food chain or food web.

100 000X more concentrated _____________________________________________________________________ b. Calculate how much DDT you would consume if you ate 3 kg of squid (calamari). _________________66 000 mg or 66g____________________________________ c. Calculate how much DDT you would consume if you ate 3 kg of fish. __________________129 000 mg or 129 g_________________________________ d. DDT has also been identified as a cancer-causing chemical. In light of these findings,

which is the healthier food choice in this case, fish or squid? Explain your answer

with reference to the food web above. Squid is healthier, it would have less pesticide per gram due to its lower position on the food web.

4. Fill in the blanks: The Hydrological (Water) Cycle

The Hydrological Cycle: condensation snow(precipitation) runoff evaporation rain(precipitation) transpiration

runoff respiration percolation, seepage, leaching ocean surface water (lake) groundwater(water table) For each of the following statements, circle True if you feel it is correct, and False if you believe it is incorrect. For each one that is false, write a correct statement in the space provided.

a. Hydrogen bonding enables water to dissolve a wide variety of substances. T or F Hydrogen bonding causes water molecules to bond to each other and also to other polar molecules, which causes dissolving

b. Liquid water is less dense than ice because hydrogen bonds hold molecules

apart in an open crystalline structure in this phase. T or F Ice is less dense than liquid water because its crystal structure separates the molecules uniformly

c. Water is most dense at 0 °C. T or F Water is most dense at 4 degrees Celcius

d. Cohesion refers to the attraction water molecules have for each other. Adhesion refers to the attraction water molecules have for molecules of other substances. T or F

e. Water has a low heat capacity and thus requires large amounts of heat to effect a small change in temperature. T or F

This is the definition of a high specific heat capacity, which is true for water

f. A hydrogen bond occurs between two hydrogen atoms on the same water molecule. T or F

Hydrogen bonds occur between the hydrogen of one molecule of water and the oxygen of another molecule of water

g. Metabolic water is generated by metabolic reactions. T or F Metabolic water is a by-product of the reactions of cellular respiration

h. Drought decreases plant productivity because plants close their stomata to

reduce water loss and can no longer take in carbon dioxide. T or F

i. The hydrologic cycle does not play a role in biogeochemical cycles. T or F

Water transports many water-soluble materials in cycles (eg. Sulfates, phophates, nitrates, etc.

j. Unlike carbon dioxide, water vapour is not a greenhouse gas. T or F

Water vapour is one of the main greenhouse gases on earth 5. a) How is the movement of matter through an ecosystem different than the movement of energy? ______________________________Matter moves in cycles, always being recycled by decomposers to be used again, energy continually enters systems from the sun, and is eventually lost to space ___________________ b) Why do you think Earth is often referred to as a closed system with regards to matter but an open system with regards to energy? ________The earth constantly loses energy to space, but matter is continually recycled on earth and is not lost.________________ 6. Fill in the blanks. a) In the hydrologic cycle, __transpiration__ refers to water loss by plants. Loss of water from a lake or ocean is ___evaporation___. The hydrologic cycle is driven by ____energy___ from the Sun. b) At each step in a biogeochemical cycle, substances are temporarily stored in ______compounds/organisms_____. When substances cycle between these relatively quickly, they are said to be part of the __________’fast’ cycle___ of nutrients.

c) Plants and algae use sulfur in the form of __sulfate___, which dissolves readily in water. Sulfur compounds spend the least amount of time in the _____air___. __________Acid deposition (rain)_____ returns sulfur in the air to the soil and water. d) Bacteria convert nitrogen gas into ammonium in a process called __________ammonification___. The process known as ____denitrification__ converts nitrite or nitrate back into nitrogen gas.  e) Phosphorus does not cycle through the __atmosphere____. Excess phosphorus in an ___aquatic__ ecosystem can result in a ______algae bloom (or eutrophication)_____. 7. Explain how the carbon and oxygen cycles are interconnected. Carbon and oxygen both cycle through living systems during cell respiration and photosynthesis. Cell respiration produces carbon dioxide which contains both carbon and oxygen atoms. These are incorporated into living organisms in the form of carbohydrates and other organic compounds and eventually recycled by decomposers. 8. What is the main difference between nitrogen fixation and ammonification? How are these two processes similar? 8. The Carbon Cycle: Fill in the Blanks:

1. Burning Fossil Fuels produces carbon dioxide 2. Carbon dioxide in the atmosphere 3. Uptake of carbon dioxide by photosynthesis 4. Uptake of carbon in organic compounds like carbohydrates by animals 5. Dead bodies and excretia 6. Decomposition produces carbon dioxide 7. Uptake of carbon in organic compounds like carbohydrates 8. Plants in some periods may produce carbon dioxide when photosynthetic rates are low.

9. In front of each of the following definitions, place the letter for the term that best fits the description. Answers may be used once, more than once, or not at all.  A) Biotic B) Abiotic C) Organism D) Species E) Population F) Community G) Ecosystem H) Biosphere  1. _E_ The number of organisms of the same species living in a community. 2. _B_ All the non‐living physical factors that influence living things. 3. _C_ A single living thing. 4. _E_ The number of goldfish living in the pet store tank. 5. _H_ The entire surface of a planet where life is found. 6. _G_ A system of living things that interact with each other and with the physical world. 7. _A_ All the effects caused by living things. 8. _D_ All the organisms that can interbreed under natural conditions to produce fertile offspring. 9. _F_ An abandoned city lot that supports cats, mice, chickadees, ants, crabgrass, and dandelions. 10. _For A_ All the living things found in the school grounds. 11. _B_ A non‐living factor, such as the amount of oxygen, that influences the living organisms. 12. _F_ Polar bears live on ice floes in Hudson Bay with bearded seals, ringed seals, herring, krill, and algae. 13. _E_ The number of humans in your classroom right now. 14. _A_ Life does not exist on Venus; therefore, it cannot be called this. 15. _H_ All of Earth’s biomes, when considered together. 16. _E_ The number of dogs living in Red Deer. 17. _C_ A cat sleeping in a chair. 18. _F_ All the plants, animals, fungi, and single‐celled organisms found in a fish tank.  10. Acid Rain

On the diagram above, label the components in the cycling and production of acid rain.

H2 0 + SO3 H2 SO4

Acid rain leads to runoff

11. The Phosphorus Cycle: Fill in the Blanks

The Nitrogen Cycle: Fill in the Blanks