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Community Ecology > Midterm > Flashcards

Midterm Flashcards

1
Q

Fundamental niche vs realized niche

A

fundamental - the multidimensional set of conditions an organism needs to survive

realized - the actual niche of a species whose distribution is restricted by biotic interactions (competition, predation, disease, parasitism)

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2
Q

competition

A

the tendency of plants to utilize the same quantum of light ion, mineral nutrient and molecule of water

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3
Q

competitive exclusion principle

A

two species with identical niches cannot coexist indefinitely, therefore coexisting species should occupy different niches

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4
Q

the study by robert and John mcarthur included foliage height and bird species diversity, what was the outcome?

A
  • forests with greater foliage height diversity support high bird species diversity
  • plant communities with low foliage height diversity support low bird species diversity
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5
Q

what is the paradox of the plankton

A

although resources needed are constant, heterogenicity in abiotic conditions and resource distributions allow coexistence

  • plankton lives in open waters and compete or the same nutrients (N,P,Silica) but they coexist
  • exclusion or coexistance is dependent on ratio of silicte and phosphate not absolute amount of nturients
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6
Q

david tillman did a study on the niches of algae, what was the outcome?

A

two species could coexist where the population of each is limited by a different nutrient

  • cyclotella dominates where silicate is most limiting to pop growth and asterionellla dominates where phosphorus is most limiting to pop gorwth
  • when each pop is limited by a nifferent nutrient there is coexistance!
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7
Q

tillmans landmark work clearly shows what?

A

that heterogeneity in resourse ratios, a form of environmental compelxity, influence community structure

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8
Q

tillman state for a given species (2 things)

A

what are the resources and how variable the resources are

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9
Q

what was robertsons study in the abandoned agricultural field?

A

studied NO3 concentrations and moisutre over 0.5 hectar area with 301 sample points
- they found there was a >10fold difference in measured variables, and little correlation between NO3 and moisture, there was sufficient spatial variability to affect plant community structure

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10
Q

what was the study with bell and factors affecting sedge distributions in deciduous forests?

A
  • utilized 11 clones of widespread carex species
  • established 3-1000m transects in differnt areas and transplanted the clones at 10m intervals
  • survived in areas of higher diveristy
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11
Q

Ecology

A

the study of interactions among organisms and their environment

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12
Q

Population ecology

A

Scientific study of structure and dynamics of populations

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13
Q

Community ecology

A

the study of interactions occurring within a prescribed area between species (interspecific) and between species and their environment and the effects this has on community structure and function

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14
Q

Interactions determine _______ level responses

A

community

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15
Q

what is an ecological service?

A

communities do things if there are societal benefits these are call

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16
Q

what is community structure?

A
  • number of species S (richness)
  • Relative abundance of species
  • which species are present and aren’t present
  • horizontal, vertical, and diagonal linkages
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17
Q

species diversity takes into account both ________ and _______

A

numbers and abundance

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18
Q

differentiate alpha beta and gamma diversity

A

alpha - diversity found within a small area (ex. patch of forest or grassland)

beta- diversity is a measure of how different patches are from each other

gamma - diversity is the total diversity found within the entire area, which includes all

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19
Q

** what are some alternatives to species based approaches?

A

a taxon approach - focus on related species ex. gray wolves, eastern wolves, coyotes etc

A guild approach - ex. seed eating of Borel forest includes mammals, birds, insects, all interact to form a community, not all taxonomically related

Life form approach - ex. non species based approach based on location of overwintering buds, including ranker life for, based on location of the buds that give rise to new shoots

Functional approach - ● Based on how plants make a living (different photosynthetic pathways) C3, C4, CAM plants

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20
Q

Guild

A

a group of organisms that make their living in a similar way

21
Q

Dominance

A

one or more species are substantially more abundant than other species

22
Q

_______ ______ is one of the most fundamental aspects of community structure

A

relative abundance

23
Q

what is log normal distribution?

A

bell shaped curve, most species have an intermediate abundance

24
Q

log normal distribution is affected by ?

A

sample size

25
Q

the more species sampled the more _____ species observed

A

rare

26
Q

you see a more intense distribution when you sample more comprehensively meaning ____ ______ ______ because of rarer species found

A

left hand sided

27
Q

how do you find the Shannon Weiner index?

A

you find the p value which is the # of individuals found for the species divided by the total individuals (do this for each species) then you multiply each p value by log(p) then you sum all the p values and apply the -

28
Q

the greater the diversity index means?

A

the more diverse the community

29
Q

pilous J measures species ____

A

eveness

30
Q

evens ranges from ___ - _____

A

0-1

31
Q

how do you find pilous J?

A

the Shannon weir index divided by logS which is species richness (ln5)

32
Q

what does evens describe?

A

the distribution of individuals

33
Q

with rank abundance curves, the more horizontal the slope the ______ the evenness

A

greater

34
Q

there is a strong correlation between habitat diversity and _______ level diversity

A

community level

35
Q

diversity increases with evens (T/F)

A

T

36
Q

for rank abundance curse the abundance rank is the ________ species and the proportional abundance is the _____ value

A

total #, p

37
Q

what is the difference between the node and the internode with plants?

A

node - point of attachment for each leaf

internode - space between the node

38
Q

what does it mean to propagate plants?

A

take a piece from the node and it will produce an axillary bud and adventitious roots

39
Q

diversity is important for richness, abundance, diversity and spatial distribution (T/F)

A

T

40
Q

what is the difference between fens and bog?

A

fens - groundwater fed, mineral rich, higher pH

Bogs - rainwater fed, lower nutrients, minerals and pH is lower

41
Q

the northern hemisphere has ____ of all peatlands

A

1/3

42
Q

describe the 2 main ways to evaluate the impacts of biodiversity on the delivery of ecological services?

A
  1. establish a species pool (gamma diversity)

2. choose a subset and grow in experimental plots (alpha diversity) and compare productivity

43
Q

what was the reich study in cedar creek Minnesota?

A

they studied grassland communities in which they used measurements of 9x9 areas and 13x13m plots, and tested the relationship between biodiversity and ecological services

44
Q

What causes diversity function relationships?

A

a given ecological service will be highest in which a community has the highest microenvironment

45
Q

Balvanera studied what?

A

summarized 103 studies

  • rarified the relationship between diversity and procuvtivity
  • diversity affects primary consumer/producer abundance rise versa along with secondary and tertiary
46
Q

Complementarity

A
  • a given ecological service will be highest/fastest in a community in which all resources/micro-environments are being exploited or occupied
  • a single species may not occupy the full niche space available
  • function will increase until all niche space is exploited
47
Q

Facilitation

A

some species enhance the growth of other

- reducing soil salinity, modifying water availability, nurse plants

48
Q

the study with the Caddisflies, was facilitation or complementarity?

A

facilitation as filter feeding was typically higher in mixed groups with different species than single species groups.

49
Q

zhu studied the genetic diversity with rice crops, what was the outcome?

A
  • mixed genotype planting vs monocultures were more effective at reducing disease
  • eliminated the need for fungicide

Community Ecology (2 decks)

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