bio quiz 17/18/pop. growth

linear: growth rate formula and description

• dN / dt = c

• constant and independent of pop. size

unrestricted exponential: growth rate formula and description

• dN / dt = rN

• proportional to population size

logistic: growth rate formula and description

• dN / dt = rN((K MINUS N) / K)

• influenced by difference between k & pop. size

Compare the birth rate to the death rate during the lag, log, and stationary phases of logistic growth

• lag: birth > death, but slow growth bc of small pop.

• log: birth > death, but rapid growth bc of large pop.

• stationary: birth = death, growth = 0

A fish farmer wishes to raise the population level by simply adding more fish to the pond. Will this work in the long term? Why or why not? What should he do instead

• no if pop. already at carrying capacity

  • bigger pop. will decline towards k & become steady at old level

  • best to increase k & allow pop. to expand naturally to new higher level

What seems to be the carrying capacity (K) in this case? How can you tell?

pop. size where pop. levels off (K = 200)

relationship between initial pop. size and c.c.

N/A (no affect)

how to distinguish limiting factor out of environmental factors

limiting factor affects k when the factor is changed

which graph is competition and which is predation and why

• competion: A (species 2 is the loser, like data presented in lab)

• predation: B (oscillations look like predator-prey data in lab)

all organisms are primarily composed of what 6 elements?

CHONPS

1. Carbon

2. Hydrogen

3. Oxygen

4. Nitrogen

5. Phosphorous

6. Sulfur

significance of CHONPS (provide examples)

building blocks of biological macromolecules

• lipids: CHOP

• carbohydrates: CHO

• DNA, RNA: CHOPN

• proteins: CHONS

unlike energy, matter is _ and how

recycled

• limited amount of CHONPS

• each element cycles in/out of living systems differently

primary reservoir

where the element is usually not part of an organism

PR for CHONPS

atmosphere and water

• PR for C: CO₂ in atmosphere

• PR for N: N₂ in atmosphere

• PR for O: H₂O molecules
  PR for H: H₂O molecules

sediment

• PR for P & S: soil and ocean beds

cycling pattern of CHONPS

elements cycle between reservoirs and organisms

→ reservoir of element → incorporation → organisms → return →

why is CHO cycling important

• connects photosynthesis & cell res

  • critical components for all biological macromolecules

nitrogen

• needed for proteins and nucleic acids

• no shortage (atmosphere 80% N₂)

• problem: atmospheric N₂ unusable for most organisms (very stable & unreactive)

nitrogen fixation

how nitrogen enters ecosystems from reservoir in atmosphere

• nitrogen-fixing bacteria convert unusable inert N₂ → reactive usable ammonia & nitrate

  • NFB live in soil & on roots of some plants

nitrogen recycling

1. Plants incorporate NH₃ & NO₃ into macromolecules

2. N containing MMs are taken up by consumers → taken up by decomposers

3. decomposers in soil convert nitrogen in MMs back into NH₃ & NO₃ (soil)

nitrogen sources

• N recycling provides 95% of N needed for living things, N fixation provides 5%

• N returned to air as N₂ via denitrification (also done by bacteria)

nitrogen fixation in agriculture

• global crop production supported by N-containing fertilizers (made by industrial nitrogen fixation)

• indistrial scale production of N w/ fertilizers has doubled natural rate of N-fixation

• 1-2% of world’s energy supply used to fix N for use in fertilizers

phosphorus is important for

• nucleotides (ex. ATP)

• nucleic acid polymers (RNA/DNA)

• phospholipids (plasma membranes)

phosphorus cycle

1. plants & other organisms incorporate P from sediment

2. consumers eat plants, decomposers eat each other

3. plants/consumers die & decomposers return P to sediment

4. plants incorporate it again & cycle restarts

sulfur important for

• certain amino acids (proteins)

  • critical for protein folding

sulfur cycle

1. plants & other organisms incorporate S from sediment

2. consumers eat plants, decomposers eat each other

3. plants/consumers die & decomposers return S to sediment

4. plants incorporate it again & cycle restarts

reduction/oxidation (redox) rxns

• when molecules gain/lose e-

• OIL RIG

  • Oxidation is Loss (of e-)

  • Reduction Is Gain (of e-)

how are redox rxns coupled

• as molecules gain e-, they are Reduced

• so other molecules must lose e- and be Oxidized

redox rxns in cells: order

• ordered sequence (e- pass from one molecule to next) in ETC

electron carriers in ETC

molecules that make up ETC

• ECs accept e- (become reduced) and donate e- (become oxidized)

• e- bind to redox center of ECs

redox potential of ECs in ETC and what are ECs/ETCs critical for

• different ECs have different affinities for e-

  • first EC in ETC has lowest RP, each following EC has increasingly more RP, last EC has highest

• ECs & ETCs critical to photosynthesis & cell res

photosynthesis and what is its efficiency of transfer (what does this mean)

• sunlight + carbon dioxide + water → glucose (sugar) + oxygen

• light energy powers glucose production (energy transferred)

  • efficiency of transfer 30%: 30% of photon energy stored as chemical energy in glucose

site of photosynthesis

chloroplasts

• thylakoid membranes have pigments (chlorophylls) that capture light energy

• stroma is where glucose is made

two parts to photosynthesis

• light rxns (light-dependent): occur at thylakoid membrane

• dark rxns (light-independent, (Calvin Cycle, Calvin-Benson Cycle): occur in stroma

light reactions requires/inputs and produces/outputs

inputs

• light as energy source

• water as e- source

• ADP + P_i for ATP synthesis

• NADP+ as e- carrier (oxidized form)

outputs

• ATP (used in ATP hydrolysis to release G)

• NADPH (e- carrier, reduced form)

• O₂ as byproduct

dark reactions requires/inputs and produces/outputs

inputs

• carbon dioxide as carbon source

• ATP from light rxns as energy source

• NADPH from light rxns as e- source

outputs

• glucose (energy storage molecule)

• ADP + P_i (from ATP hydrolysis)

• NADP+ (FROM NADPH oxidation)