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Organisms and Environment > Populations > Flashcards

Populations Flashcards

(59 cards)

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1
Q

Ecology

A

Scientific distribution and abundance of organisms and interactions that determine these and biodiversity => individual, population, community

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2
Q

Ecological niche

A

Sum of total adaptations of an organismic unit

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3
Q

Niche

A

Role of an organisms in its community (not out competed). Includes: foraging strategies, diet, reproductive strategies, social organisation, predators, environment tolerances, morphology, sense adaptations, physiology, competition

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4
Q

Life zones depend on

A

Humidity and ppt

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5
Q

Charles Elton 1927

A

A niche is a place in an environment, with relations to food and enemies

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6
Q

Cause 1934

A

Competition, 2 similar species scarcely occupy similar niches - certain peculiar types of food etc.

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7
Q

Competitive exclusion principle

A

Complete competitors cannot exists

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8
Q

Niche segeration

A

Higher species richness = higher efficiency of conservation costs

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9
Q

Hutchinson’s model fall backs:

A

Not all niches environmental, some behavioural
Not all axes linear
Different species can hold similar niches - same species different niches
Once a niche is vacant, other organisms can fill the position

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10
Q

Fundamental niche

A

Entire set of conditions under which a species can survive and reproduce => larger

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11
Q

Realised niche

A

Set of conditions actually used by species after interactions with other species are taken into account => different locations

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12
Q

Specialist niches

A

Smaller niches than generalists

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13
Q

Levin’s measure of niche breath

A

B = 1/ total (pi^2)
Pi = probability of individuals that use resource i or probability of diet consisting of i
Niche breath is important so that there is no niche overlap
There is a constant niche breadth
But we do not know how many individuals are in the niche

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14
Q

Niche overlap

A

Coexistence, including overlapping => hyperspace, reciprocal overlap, asymmetric overlap (pushed out original niche), non-overlapping: abutting, disjunct

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15
Q

Classification of non-overlapping niches

A

Resource limiting => competition currently occurring, abutting niches indirect indication => niche divergence (competition)

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16
Q

Niche partitioning

A

Narrow niche - coexists with other species -> more specific. Wide niche - single species on island

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17
Q

Competitive release

A

Take out one species, another may expand its niche

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18
Q

Explanations for different niches

A

Competition, evolutionary competition avoidance, (Connell 1980 ‘ghost of competition past’ - competition most = red - breeding success, natural selection eliminates niches more distinct from completion spectrum), evolution in response to natural selection - independent

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19
Q

Population

A

A group of interbreeding individuals in a given area at a given time
Number of individuals, population density/area, BR + DR id randomly distributed, or mobile = single density. Not all individuals in the population are the same => structured population (age or stage-structured)

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20
Q

Individual

A

Unitary species - zygote (sexual reproduction) => eugenically unique organism
Modular - zygote => similar modules - expand, new individual

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21
Q

Genet

A

Individual from SR

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22
Q

Ramet

A

Module reproduces AS by genet (same genotype)

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23
Q

Population distribution

A

Spatial location of individual - stationary (sessile) or vary (migration). If movement between groups of individuals is less frequent = local populations

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24
Q

Metrapopulations

Study These Flashcards
A

Sub-populations linked by dispersal, groups of populations connect by immigration an emigration => larger regional population. Key premises: local breeding and migration

25
Life tables
Summarise/infer patterns or B and D => overtime follows cohort and record structure at some point in time
26
Age-sructrured census
Census at single point in time. Multiple can reveal important events over time=> infer multiple cohort dynamics.
27
Nt+1 =
Nt + Br - Dr + It - Et Nt = number of individuals at time t, Br/DR between time t and t+1 It = number individuals immigrating t - t+1 Et = number individuals emigrating t - t+1
28
Why do we estimate populations
To manage ans conserve species and understand BR/DR | Total individual counts, or sampling methods, estimate relative density e.g. facial pellets
29
Model of populations, N(t) =
N(o) x e^rt | r = intrinsic rate of geometric population increase
30
Population regulation - dN/dt
Stabilises populations and stops exponential growth dN/dt = r (1 - N/k) v K = population carrying capacity (max) N = population size Higher N = closer to k N is small => dN/dt = rN (exponential growth) N = k/2 => growth rate is highest dN/dt very small = population size levels off dN/dt neg => population declines to k
31
Interspecific reactions: Competition
-/- use same resources and insufficient to supply the combination of needs
32
Interspecific reactions: Predation
+/- one organism consumes all or part of another, also herbivory and cannibalism
33
Interspecific reactions: Paratism
+/- Close association with hosts - feed on (don't always kill) => micro parasites multiply within host survive, macrparasites grown in/on host, don't multiply
34
Interspecific reactions: Amensalism
-/0 e.g. large mammals 0, plants near waterhole -
35
Interspecific reactions: Comensalism
+/0 e.g. egret cattle capture more insects when with large animals - egret +, buffalo 0
36
Interspecific reactions: Mutualism
+/+ both individuals benefit => facultative pollinations, seed dispersal, permanently paired, at least 1 cannot live independently (obligate)
37
Predation and population change
Predator/prey cycles e.g. low red = inc in prey = inc in red = dec in prey = dec in pred
38
Gross primary productivity
Rate energy is incorporated into bodies of photosynthetic organisms (5% solar energy)
39
Gross primary production
Amount of accumulated energy (metabolic, growth, reproduction)
40
Net primary production
Energy available to primary consumers
41
How does temperate and moisture affect biomass?
Warm air = more evaporation and transportation rates Low temps = low photosynthesis and low production NPP at equator = high m ++ = high NPP Decrease in ppt and temp = decrease in biomass
42
Trophic levels
Divided on how energy is obtained
43
Assimilation efficiency
Assimilation: ingestion (I) => A + Expelled
44
Production efficiency
Production: assimilation A => respiratory + P
45
Detritivores
Eat dead and water
46
Omnivores
pp and another trophic level
47
Energy available to given trophic level
Productivity of next lower level (n-1)
48
Consumption efficiency
Ingestion: production (ln/Pn-1)
49
Food chain
Sequence of interaction => feeding - short, energetic
50
Food web
Interconnected food chains. Apex predator - no predators itself
51
Keystone species
Strong influence on ecosystem but low abundance
52
Trophic cascade
Change in species community at 1 trophic level affects species community at trophic level not directly above or below e.g. predators reduce herbivores = increase in plant biomass
53
Community importance for a species, Clx
Species lost during the removal of species X = ((tN - td)/tN)/Px tN = quantitative measure of community trait in intact community td = quantitative measure of community trait after species x removed px = proportional abundance of species x before removal
54
Community stability
Equilibrium model Most natural comms on a continue stable => unstable Measured as time to recovery from disturbance or variability of comm over time
55
Stable community
Many interactions (competition and predation), processes operate in a density dependent manner to regulate population sizes, species saturation rare, catastrophic environmental events
56
Local stability
Environmental changes, communities replaced
57
Global stability
Maintains itself
58
Food web generalisations
More species = more linkages, chain lengths short, proportion of species at each level approx constant, omnivory common
59
How can you study food webs using stable isotopes?
Ratio of isotopes expressed as theta values (parts per 1000). On average thetaN increases by 3.4% in animals relative to their diet => separate animals from different trophic levels. Bioaccumulation.

Organisms and Environment (9 decks)

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