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Biol 313- Principles of Ecology > Midterm > Flashcards

Midterm Flashcards

1
Q

Define ecology.

A

The study relationships organisms and the environment.

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2
Q

Define evolution.

A

The change over time in individual organisms that differ genetically in one or more traits.

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3
Q

Microevolution vs. Macroevolution

A

The change in gene frequencies WITHIN a population within a SINGLE species. (Mutation & Genetic drift)

The changes over time in the proportion of species that determines the biodiversity (Speciation & Adaptive Radiation)
• Leads to the creation of NEW or DIFFERENT species
You need microevolution to get to macroevolution

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4
Q

Define natural selection.

A

Different genetic contributions by particular phenotypes to the next generation.

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5
Q

Define fitness.

A

The average contribution of genes to the next generation by a particular phenotype in a particular environment.

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6
Q

Define adaptations.

A

The process by which populations of organisms evolve in such a way as to become better suited to their environment as advantageous traits become predominant.

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7
Q

Explain the 4 key aspects of natural selection and provide examples.

A
  1. More offspring are produced each generation than can be supported by the environment
    (Not everybody can survive bc of competition)
  2. Diff. btwn individuals in a pop. and some of these variations are heritable
  3. Individuals w advantageous traits have a higher chance of surviving/reproducing than other members= increased fitness (non-random)
  4. Traits that result in increased fitness will become more present in a pop. over time
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8
Q

Processes that alter the proportions of different “types” in organisms. (in micro and macroevolution)

A

microevolution- genetic drift (occurs randomly) and natural selection
macroevolution- adaptive radiation (ex. Darwin’s finches)

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9
Q

Natural selection vs. Mutation and Genetic Drift (4 differences)

A
  1. NS causes random changes, M and GD occur by chance
  2. NS depends on genotype/phenotype while M and GD need to be heritable (genotype)
  3. NS involves ecological interactions
  4. NS results in adaptation
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10
Q

3 conditions for natural selection

A
  1. Phenotypic variation
  2. Different fitnesses w different phenotypes
  3. Inheritance (Genetic response)
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11
Q

Describe the 4 modes of selection

A
  1. Stabilizing- average phenotype does best, acts against extremes, decreases diversity
  2. Directional- only 1 extreme phenotype is favoured, decreases diversity, decreases diversity over time
  3. Disruptive- BOTH extremes favoured, acts against average phenotype, increases biodiversity
  4. Frequency Dependent- occurs when ind. fitness depends on frequency of other phenotypes
    Game Theory (-) - when fitness of phenotype decreases as it becomes more common
    Mimicry (+) - fitness of phenotype increases
    Evolutionary Stable State (=) - all phenotypes have same fitness
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12
Q

Species as defined by the Biological Species Concept

A

A species is a group of organisms that is reproductively isolated from other groups (only interbreeds w one another).

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13
Q

Define speciation. What are the 3 types of speciation? Give examples of each

A

speciation= interruption of gene flow btwn pops. that formerly interbred to create new species

  1. Allopatric- geographically subdvided (allo=different, patria=country) (ex. darwin’s finches)
  2. Parapatric - no spatial barrier, when a pop. expands into a new habitat from within (para= beside) (ex. the grass a.tenuis can inherit the trait to withstand contaminated soil or it will do poorly in it)
  3. Sympatric- from 1 parent pop., a reproductively isolated pop. forms (ex. fruit flies of the same species evolved to have diff. diets, one eats hawthorns the other eats apples)
    - driven by natural selection
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14
Q

Define physiological ecology.

A

The study of how animals cope with factors of their physical environment.
An increase in extreme environments increases their response

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15
Q

Explain the difference between physical resources and physical conditions. (Both abiotic factors)

A

Resources- consumed/made less available to others

physical conditions- things that organisms respond to differently (varies in time/space)

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16
Q

How does a performance curve differ for endo and ectothermic organisms?

A

endotherms- have a thermal neutral zone where there’s no change to the metabolic rate
ectotherms- Has a performance optima (certain temp. has the highest performance) within a thermal tolerance range

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17
Q

What physiological processes lead to the observed performance curves?

A
  • lower critical thermal limits (at some point, it gets so cold the organism freezes to death)
  • marginal stability- as temp. increases, flex of molecules increases which increases the biological rate to reach the performance optima
  • reduction in metabolic efficiency= less efficient at making ATP
  • oxygen limitation and fermentative metabolism(less eff.) = decreased performance
  • cellular stress (heat shock proteins) - refolds denatured proteins which costs ATP and decreases performance
  • membrane integrity- inefficient barrier=loss of function
  • upper critical thermal limits- too hot to recover=organism dies
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18
Q

Describe how diff. environmental factors can interact to form a “response surface.”

A

Abiotic factors (Ex. temperature, humidity) have a value that maximizes an organism’s fitness.

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19
Q

Define distribution limits and give some examples.

A

where an organism is found spatially/temporally either on small/wide geographic scale.
ex. intertidal zones- have many different environmental conditions in a small area, latitude affects upper limit of tree species

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20
Q

Implications of climate change- how do different organisms respond to climate change according to area?

A

Tropical organisms are more negatively affected bc change in temp. is closer to the optimum. (smaller range of temps. they can survive in)
Temperate environments are more positively affected bc wider range of temps mean change in temp. is below the optimum.

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21
Q

adaptation vs. acclimation

A

adaptation= genetic changes in physiology/morphology via natural selection that results in permanent shift

acclimation= reversible/short-term changes in physiology/morphology bc of exposure to environmental stress

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22
Q

limits to the ability to acclimate bc of climate change vs. limits to adaptive responses

A

species w greater tolerance to high temps. are less able to acclimate to high temps. (ex.tropical animals)

diff. organisms have diff. limits and must have trade-offs to allocate resources to a function

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23
Q

define behavioural ecology

A

how behaviour influences fitness/interaction w environment

* behaviours are shaped through natual selection on different phenotype)

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24
Q

explain Charnov’s patch model (When does the organism leave the patch?)

A

Charnov’s Patch Model (marginal value theorem)-

  1. foragers should abandon patch when max energy gain is reached
  2. foragers should stay in higher quality patches for longer
  3. If the same quality, time in patch should increase if time spent travelling to the patch is increased
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25
Q

explain optimal diet model (what prey items to include in the diet?)

A

forager time is spent searching and handling
profitability of item = energy value(kJ/ind.) / Handling time(s)
*specialist= searches for most profitable item (P1)
generalist = eats less profitable item (P2)

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26
Q

define optimal foraging behaviour

A

natural selection influences how organisms feed/behave while foraging
- likely to favour ind. within a pop. that are more efficient at acquiring limited resources

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27
Q

Define functional response.

A

The relationship between rate of feeding of an individual predator and the density of a prey item.

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28
Q

Explain how Type l, Il and Ill functional

responses differ

A

Type I- increasing number of prey increases feeding rate of predator (positive linear), no handling time
- slope=efficiency of predator/ proportion of prey density consumed

Type II- feeding rate increases before maxing out

Type III- at low densities, feeding rate increases slowly

29
Q

Consider the implications of the functional

responses from the ‘prey’ species’ perspective

A

Chances of prey survival are highest for Type III predators.

Lowest chance of prey survival for Type I predator (consistently high consumption of prey).

30
Q

Explain the concept of Ideal Free Distribution

and how it relates to optimal foraging theory (How do they distribute themselves to patches of different quality?)

A
  1. Number of ind. that will aggregate in various patches is prop. to amt. of resources in a patch (an increase in resources will increase the presence of individuals)
  2. The pay-off for an ind. will be equal in all patches

Assumes the ind. can accurately judge the quality of the habitats and are free to move btwn patches

31
Q

Define sexual selection, secondary sexual characteristics, intra/intersexual selection

A

sexual selection- phenotypic selection based on differences in mating/fertilizing ability

secondary sexual characteristics- characteristics of males/females that are not directly involved with reproduction

intrasexual selection- individuals of one sex competes amongst themselves

intersexual selection- choosing mates of the opposite sex based on a particular trait

32
Q

Describe Bateman’s principle and the exceptions derived from this principle

A
  1. Reduced investment in gametes/parental care
    by males increases their potential rate of
    reproduction, biasing the relative numbers of
    sexually active males to receptive females at any
    one time.

2.This leads to increased intensity of intrasexual
competition, greater variance in breeding success
and stronger selection for traits affecting
competitive ability in males than in females.

  1. This leads to greater selectivity in choice of mating
    partners by females
  2. Which generates selection pressure males for traits that display their quality as breeding partners. i.e. secondary sexual characteristics.

Exceptions:

  • females can have more than one mate
  • males can be choosey
33
Q

List the different life history traits

A

-Size at birth
-Length of life
-Number, size and sex of offspring
-Rate and pattern of growth
-Age at sexual maturity
-Size at sexual maturity
-Age and sex specific reproductive investment
(eggs vs. sperm)
-Mortality schedules

34
Q

Explain why the Principle of Allocation

influences the life history patterns we observe.

A

Trade-offs- finite energy budget
Principle of Allocation = if an organism can acquire
a limited amount of resources/energy
for which two different processes compete, then an
increase in resources to one, must result in an equal decrease of resources to another.

35
Q

Explain why trade-offs arise from the Principle of

Allocation.

A

Must determine how much energy to put towards reproduction and growth.
How should resources be put towards reproductive effort? (size vs number)

36
Q

Explain the size vs. number reproductive trade-

off.

A
  • as number of offspring increases, amount of parental investment decreases and size of offspring decreases which decreases chances of survival
  • as number of offspring decreases, they are larger and have a better chance of surviving with increased parental investment
37
Q

Explain the trade-off between growth and

reproduction.

A

Allocating resources for reproduction may decrease available energy for growth and decrease future reproduction.

38
Q

Describe r vs. K strategies. What conditions are best for both?

A

r = population growth rate
- best conditions are decreased competition and densities

K = max. sustainable population (carrying capacity)
- best conditions are increased competition and increased investment in offspring

39
Q

List characteristics of r vs. K strategists

A

r

  • fast growth rates (adapts better for disturbed habitats) but smaller in size
  • many small offspring (reproduces once)

K

  • traits favor eff. use of resources
  • slow growth rate but larger in size
  • few large offspring (reproduces many times)
40
Q 
Describe 3 strategies of Grime's classification of life 
history strategies (plants). What 2 selective pressures does it suggest to be most important?
A

Suggests disturbance and abiotic stress are most important as well as competition.
1. stress tolerant (most like K) - favors low disturbance but high stress, grows slowly, evergreen, good nutrient retention

  1. Competitive (neither)- favors low disturbance and stress, grows fast, good at competition (ex. Birch)
  2. Ruderal (most like r) - favors high disturbance but low stress, grows fast, short gen. time (ex. grass)
41
Q

Describe Winemiller and Rose’s life history

strategies (fish). What are the 3 endpoints on the adaptive space surface? Give examples.

A
  1. opportunistic (more like r)- low juvenile survival, low number of offspring, early rep. maturity (lives quickly and dies younger) (ex. birds)
  2. Equilibrium (most like K) - high juvenile survival bc of increased parental investment, low number of offspring, late reproductive maturity (ex. sharks)
  3. Periodic (neither) - low juvenile survival, high number of offspring, late reproductive maturity, (ex. sturgeon)
42
Q

What type of life history is more at risk of extinction?

A

K-strategists because they have slower growth rates and higher ages at maturity meaning it takes them longer to reestablish their population

43
Q

Explain:

what game theory is and how it is applied to ecology.

A

The behavioral strategies individuals adopt to maximize their individual fitness.
Ecology studies how the best strategy differs for different organisms. (aggressive vs. non-aggressive)

44
Q

Explain how aggressive strategies can invade a population.

A

Always attack others and take the resources when they win.
Wins only half the time against others of same species.
Losing means it suffers an injury cost (C).

45
Q

Explain evolutionarily stable strategy (ESS) and frequency dependent selection.

A

A strategy resistant to invasion and most likely to be maintained by natural selection.

frequency dependent- fitness of an individual depends on the frequencies of other phenotypes in the pop.

46
Q

Describe why natural selection acts on relative fitness
and how this fitness can depend on the frequency of
other “types” of individuals in the population.

A

fitness depends on behavior of others - neither strategy was better
positive freq. dep. = majority phenotype wins
negative freq. dep. = minority advantage creates more diversity and results in a combination of phenotypes

47
Q

Explain how coexistence of multiple behavioural

strategies in a population is possible.

A

When both strategists have the same fitness= evolutionary stable state is reached (1:2 for aggressive:non-aggressive)

48
Q

Define population and population ecology

A

population = group of potentially interbreeding individuals of a single species inhabiting a specific area

population ecology = the study of the spatial and temporal patterns in the abundance and distribution of organisms and the mechanisms that produce those patterns

49
Q

Describe the four processes that can lead to a
change in the number of individuals in a
population (N)

A
  1. Conservation = increased pop.
  2. Pest management = decreased damage/pop.
  3. Harvest management = maxed pop.
  4. invasive species = decreased spatial/temporal spread
50
Q

Explain the difference between total and per capita

rates

A

Total rates:

  • total number of ____ for a pop.
  • represented by capital letters
  • units= births/t

per capita rates:

  • ____ rate per individual of a pop.
  • represented by lower case letters
  • Units= births/(ind*time)
51
Q

Explain how density-independent per capita rates lead

to exponential/geometric growth

A

density-independent growth = per capita birth/death rates are independent of population density

exponential growth = when per capita birth rate is greater than per capita death rates and r is positive

52
Q

Explain the consequences of incorporating
density dependence into the exponential growth
equation

A

exponential growth occurs when per capita rates are density independent so by making them density dependent, the population undergoes instantaneous negative feedback which leads to the logistic growth to the K. (Self limitation)

53
Q

Define carrying capacity, logistic growth and

density dependent growth

A 
carrying capacity (K) is the theoretical max pop size in a given location. 
Logistic growth occurs when exponential growth is scaled to the unused portion from the carrying capacity. (starts at a small pop. the initially grows rapidly before slowing down and stopping once K is reached) 
Density dependence occurs when per capita birth/death rates (b and d) depend on the population density
54
Q

List biological factors that could give rise to

density dependent rates

A

Intraspecific competition: (more ind. less available)

  • food
  • mates
  • space
  • light for plants
  • more prey means more predators
  • more ind. mean more pathogens
55
Q

What does it mean when all individuals in a

population are identical?

A

There is no age, size or sex structure (all the same age, size and sex)

56
Q

Define demography, age structure, survivorship,

and stage structure

A

demography= the branch of pop. biology dealing w pop. projections for age structured populations
age structure = can influence the per capita rates
survivorship = how many die at each age class? (the pattern of survival for ind. in a pop. as a function of age)
stage structure= when the different life stage have different vital rates (ex. larvae, pupae, juvenile, adults, eggs) illustrated by life cycle diagrams

57
Q

Explain the 3 different types of survivorship
curves and be able to provide an example of
each type.

A 
Type I = high juvenile survival, higher mortality of older ind., (usually K strategists such as Dall sheep who are easier prey after the age of 10)
Type 2 (stable) = equal mortality across all age classes (ex. robins are constantly vulnerable)
Type 3= High juvenile mortality, high survival of older ind. (ex. usually r-strategists such as C.droserifolia where only 39 plants survive out of every 1 million seeds to 1 year but then live on to be about 40)
58
Q

Explain 2 different reproductive strategies. Which strategist normally uses each one?

A

semelparity- organisms have a single reproductive event (practiced by r-strategists)
iteroparity= organisms reproduce more than once in a lifetime by different age classes (practiced by K-strategists)

59
Q

What is a life table? What do different R0 values mean? What are the units of R0? How do you calculate lx from nx?

A

Combines survivorship/fecundity schedules to estimate net reproductive rate (R0) by only following females.
R0>1= female prod > 1 offspring = increased pop.
R0<1= decreased pop
R0=1= each female prod exactly 1 offspring so pop. stays the same
Unit = per unit lifetime
lx = (nx/n0)

60
Q

Define spatial population

ecology.

A

spatial population ecology = the study of movement/dispersal from one pop. to another at 2 diff scales (local (within a patch), regional/metapopulation (dispersal))

61
Q

Explain the role of dispersal (m) in population

dynamics

A

dispersal = movement
Directly affects the proportion of sites successfully colonized and therefore the number of occupied patches (P) over time and how quickly they are colonized
* each occupied patch contributes equally to dispersal
* dispersal of individuals connect subpopulations

62
Q

Explain the ‘rescue effect’ and source-sink

populations.

A

source-sink pops- a high quality source may disperse to a poor quality sink (r<0)
rescue effect = high immigration rates protect a pop. from extinction due to frequent recolonization

63
Q

The 2 Rule of Thumb for Life History

A

1) If mortality increases for ALL age classes, reproductive effort increases early in life and age/size at maturity will decrease
2) If mortality increases after a PARTICULAR age, reproductive effort increases before and decreases after that age.

64
Q

Assumptions of exponential growth in a closed population

A 
No I or E
Constant b and d
All individuals are the same 
No age/size/sex structure
Continuous growth with no time lags
65
Q

What is the Allee effect and what are some causes of it? What’s the difference between a weak and strong Allee effect?

A

When density dependence is not a simple linear relationship. At low population densities, r can increase significantly. This is caused by limited cooperation, mate limitation, less dense plant are less attractive and do not get pollinated etc.
weak= (+) r
strong = (-) r

66
Q

Define stable age structure vs. stable age distribution.

A 
When life table values are fixed the proportion of ind. in each age class is constant. (age structure goes straight down)
Stable age distribution occurs when fecundity/survivorship are fixed
67
Q

What 4 conditions define a metapopulation?

A
  1. suitable habitat is divided into discrete patches occupies by breeding pops.
  2. even the largest patch = risk of extinction
  3. habitat patches= not too isolated to prevent recolonization
  4. pop. dynamics are not synchronized (movement but not too much)
    * a population of populations
68
Q

Define colonization and extinction. What factors affect each?

A

colonization = movement of ind. from occupied to unoccupied sites to form a new local pop.
affected by: resources, predation, competition, distance btwn patches, species’ mobility

extinction= proportion of sites that go extinct over time
affected by: extreme weather events, disease, lack of new mates which causes inbreeding, humans, predation

69
Q

Define flow diagram, mass action, state variable, parameter, epidemiology, and SIR model.

A

flow diagram- shows how ind. move from one state to another
mass action= rate of interaction that are proportional to the number of each variable
epidemiology= study of patterns that control rates of spread of disease in pops.
SIR model= Susceptibles, Infected, Recovered

Biol 313- Principles of Ecology (2 decks)

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