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MICRB 320 > Populations and Life Strategies > Flashcards

Populations and Life Strategies Flashcards

1
Q

What is a typical population

A

Defined as groups of interbreeding individuals, but this doesn’t apply to most organisms

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2
Q

What is the ecological population

A

Group of like organisms living in a defined area (same place) in a specific time (same time). This is usually defined by the investigator.

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3
Q

What is the density of size of a population

A

Number of individuals per unit area. It is a fundamental parameter that is affected by births, deaths, immigrations, and emigration

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4
Q

What is natality

A

Births including binary fission

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5
Q

What is fecundity

A

Measure of potential reproductive output

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6
Q

What is mortality

A

Measure of the death of organism

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7
Q

What are the secondary characteristics of a population

A

Age distribution, genetic composition or any other that carries out their effects on the population based on the primary characteristics

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8
Q

What happens when the r is greater than 1

A

The population will increase steadily

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9
Q

What happens when the r is less than 1

A

The population decreases steadily until we reach a zero of no population present after a period of time

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10
Q

What happens when r is equal to 1

A

We aren’t growing or shrinking so the population is constant over time. Things are coming in and things are going out at the same rate.

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11
Q

Why can’t exponential populations persist

A

Not infinite supply of food, not enough space, and wastes become toxic

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12
Q

What is the carrying capacity

A

Maximum number of individuals an environment can support

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13
Q

What is the r-selected organisms plan

A

Grow fast, high growth rate and high carrying capacity

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14
Q

What is the K-selected organisms plan

A

Grow slow, low growth rate, and low carrying capacity

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15
Q

Where do r-selected organisms win

A

They win in environment with high substrate availability (“generalists”)

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16
Q

Where do K-selected organisms win

A

Win in environment with low substrate availability (“specialists”)

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17
Q

What is the longevity of a growth phase of a r-strategists

A

Short

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18
Q

What is the longevity of growth phase of K-strategists

A

Long

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19
Q

What is rate of growth (uncrowded) for r-strategists

A

High

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20
Q

What is the rate of growth (uncrowded) for K-strategists

A

Low

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21
Q

What is the relative food allocation during uncrowded to crowded conditions in r-strategists

A

Shift from growth and maintenance to reproduction

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22
Q

What is the relative food allocation during uncrowded to crowded conditions of K-strategists

A

Growth and maintenance

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23
Q

What is the population density dynamics (crowded) in r-strategists

A

High population density of resting biomass

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24
Q

What is the population density dynamics (crowded) in K-strategists

A

High equilibrium population density of competitive growing biomass.

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25
Q

What is the response to enrichment to r-strategists

A

Fast growth after variable lag

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26
Q

What is response to enrichment for K-strategists

A

Slow growth after variable lag

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27
Q

What is mortality of r-strategists

A

Often catastrophic

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28
Q

What is mortality of K-strategists

A

Variable

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29
Q

What is migratory tendency of r-strategists

A

High

30
Q

What is the migratory tendency of K-strategists

A

Variable.

31
Q

What is “Top Down” Control

A

Dominant regulator of population density is predation - it doesn’t have to be a large predator but it can be a disease or anything else that can kill you

32
Q

What is “Bottom Up” Control

A

Dominant regulator of population density is nutrient availability

33
Q

What happens when grazing pressure exceeds bacterial productivity

A

If grazing pressure exceeds bacterial productivity, we will find ourselves in a top-down control attempt to get a stable community - defense specialists will dominate

34
Q

What happens when bacterial productivity exceeds grazing pressure

A

If bacterial productivity exceeds grazing pressure, we will find ourselves in a bottom-up control to attempt to get a stable community - competition specialists will dominate.

35
Q

What is the Leibig’s Law of the Minimum

A

Total biomass of any organism determined by the nutrient present in lowest concentration relative to the requirements of that organism.

36
Q

What is Shelford’s Law of Tolerance

A

There are bounds for environmental factors above and below which microorganisms cannot grow

37
Q

What is source of phosphorus in water

A

Source of phosphorus is erosion from rocks - there is no biological mechanism to pull phosphorus out of the atmosphere

38
Q

What is the source of nitrogen in water

A

Source of nitrogen is nitrogen fixation - nitrogen-fixing bacteria/lightning we can’t incorporate it into it has been fixed into ammonia or nitrite

39
Q

What is the source of carbon in water

A

Source of carbon is atmosphere - CO2 is being fixed by plankton/algae into carbon

40
Q

What is the Iron Hypothesis

A

If we were to add free iron to high nitrate area in the ocean can lead to fertilization. Fertilization with iron would lead to large blooms, which would then sink, removing carbon dioxide from the atmosphere.

41
Q

Why is the Iron Hypothesis not possible

A

Complex trophic interactions prevent this - many studies show no carbon sequestration. Initially there was positive results, but within a few days all that biomass was returned to the atmosphere.

42
Q

What is the predator-prey cycle

A
  1. Prey and Predator are both increasing in populations
  2. Predator increasing it leads to prey decreasing
  3. Prey decreasing leads to predator decreasing
  4. Predator decreasing leads to prey increasing
    This continues in a cycle
43
Q

How do bacteria live

A

They are free-living like plankton or surface attached like biofilm. Most bacteria that live in the environment are surface attached. Most lab studies focus on planktonic bacteria.

44
Q

How do we isolate bacteria

A

To isolate bacteria, we enrich (liquid), select colony (surface), and then do genetics and physiology with a combination of liquid and surface techniques. Liquid only isolation techniques have been used to isolate abundant, but previously uncharacterized, planktonic bacteria

45
Q

What are plankton

A

Planktonic cells are in a more homogenous environment. Common in aquatic systems like lakes and oceans. This includes zooplankton, phytoplankton, bacterioplankton, and virioplankton. Even in the water column, most bacteria lived attached to particles.

46
Q

What are biofilms

A

Biofilm cells produce their heterogeneous environment with many micro-niches. Biofilms are collections of microorganisms surrounded by the slime (extracellular polymeric substances, EPS), they secrete, attached to an inert or living surface. Bacteria in the environment predominantly live in biofilms.

47
Q

How are biofilms developed

A
  1. Reversible adsorption of bacteria - occurs in seconds
  2. Irreversible attachment of bacteria - occurs in seconds to minutes
  3. Growth and division of bacteria - occurs in hours to days
  4. Exopolymer production and biofilm formation - occurs in hours to days
  5. Attachment of other organisms to biofilm - occurs in days to months
48
Q

What are bacterial adhesins

A 
Cell Membrane
Cell Wall Structures
Intracellular Materials
Flagellum
Extracellular Polymetric Material
49
Q

Why would they form a biofilm

A
  1. Nutrients (macromolecules) collect at surfaces - source of food
  2. Protection from environment
  3. Physical proximity - allows easy exchange of products and assists with syntrophy and other forms of co-degradation
  4. Genetic exchange (horizontal gene transfer)
50
Q

How do biofilms impact swimming pools

A

Health risks and cosmetic degradation

51
Q

How do biofilms impact drinking water pipes

A

Health risks and corrosion

52
Q

How do biofilms impact food processing

A

Contamination

53
Q

How do biofilms impact dental plaque

A

Caries and gingivitis

54
Q

How do biofilms impact ships

A

Increased drag and corrosion

55
Q

How do biofilms impact household drains

A

Slowing draining sinks

56
Q

How do biofilms impact implants

A

Chronic infections

57
Q

How do biofilms wastewater treatment

A

Pass through biofilter to degrade matter

58
Q

How can microbe impact corrosion

A

Microbes are taking electrons from the surface of the material to the outside of the biofilm and dumping them on oxygen which causes a pit to form in the metal. Biocorrosion caused by bacteria results in pitting, crevice corrosion cracking. Fix with electroplating new metal onto the cracks.

59
Q

What are microbial mats

A

Thick biofilms that are some of the earliest microbial fossils. Mainly found in extreme environments

60
Q

What is vibrio cholerae

A

The causative agent for human intestinal disease cholera. It is a burden to mainly underdeveloped countries which cannot afford to establish or to maintain necessary hygienic and medical facilities. Can be isolated and estuarine and aquatic environments. Survival in the relatively harsh environment is believed to be due to its ability to form a biofilm with zooplankton or egg masses.

61
Q

During microbial strategies, what are life history strategies

A

Life history strategies represent a set of traits that tend to correlate due to physiological or evolutionary trade-offs, with different strategies favoured under different environmental conditions.

62
Q

During microbial strategies, what is the C-S-R triangle

A

Grime’s C-S-R triangle is an alternative framework that enumerates three major plant life history strategies: competitors (C) excel at maximising resource capture in productive and undisturbed systems, stress tolerators (S) prevail at continuously low-resource and stressful conditions, and ruderals (R) occupy recently disturbed but less stressful habitats

63
Q

During microbial strategies, what is the High Yield (Y) Strategy

A

High yield strategists maximise the fraction of resource uptake that is allocated to biosynthetic processes by investing in central metabolism and associated assimilatory pathways such as amino acid, nucleotide, and fatty acid synthesis to build cellular components using these precursor components. The absence of resource limitation and stress are expected to favour the high yield strategy.

64
Q

During microbial strategies, what is resource acquisition (A) strategy

A

Resource acquistion by heterotrophic microbes depends on uptake of depolymerized substrates using various membrane transporters. It is probably that investment in resource acquisition traits is higher in resource abundant environments like the rhizosphere, we propose that this strategy will prevail in low-resource conditions where microbes would be under selection to increase resource capture at the expense of growth yield

65
Q

During microbial strategies, what is the Stress Tolerator (S) Strategy

A

Certain global patterns in phenotypic expression are common, including factors or molecular chaperons aimed to minimise or mitigate biomolecular damage. Thus, microbes exposed to suboptimal conditions would posses traits linked to stress tolerance at the expense of other traits.

66
Q

During microbial strategies, how do they measure yield

A

Yield is often measured as the proportion of carbon substrate invested into biomass relative to that lost through respiration

67
Q

During microbial strategies, how do they measure resource acquisition

A

Resource acquisition traits have been estimated with omics and biochemical techniques at both the population and the community levels

68
Q

During microbial strategies, how do they measure stress

A

Stress tolerance taits in the form of factors, molecular chaperons, or specific physiological adaptations can be extracted from widely used omics tools.

69
Q

During microbial strategies, how do Y-strategists work with carbon cycling

A

Y-strategists with increased investment into growth and biomass production would contribute to microbial residue formation that can be stabilized through organo-mineral interactions or aggregation

70
Q

During microbial strategies, how do A-Strategists work with carbon cycling

A

A-strategists should contribute more to decomposition and carbon loss through investment in extracellular enzyme production. Selection for A-strategists could also occur under a lower organic matter environment that stimulates enzyme production to mine resources.

71
Q

During microbial strategies, how do S-strategists work with carbon cycling

A

S-strategists might depend on the type of stress compounds produced, by diverting investment away from growth, S-strategists could also reduce soil carbon accumulation.

MICRB 320 (6 decks)

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