all Flashcards
what is organismal ecology concerned with?
concerned with behavioural, physiological and morphological traits mediating interactions
what is a population?
group of individuals of the same species interacting in a specific geographic area
- fluctuating but measurable numbers
- variable dispersion
what does population ecology examine?
factors that limit and regulate pop size and composition
what is a community?
all individuals of all species that inhabit a particular area
what does community ecology examine?
interactions interactions among populations and how factors like predation, competition, disease, environment affect community structure and organisation
what 6 processes drive distribution and abundance?
immigration, colonisation, birth
immigration, extinction, death
what are unitary organisms?
form programmed from birth
easy to recognise genetically operate organisms
determinate structure
usually strict number of body parts
what are modular organisms?
- genetic individual (genet) begins as single celled zygote
- growth by repeated production of modules
- growth indeterminate
- structure unpredictable
- genet not dead until all modules are
in detail what are the 2 reproductive patterns?
- semelparity
- reproduce once
- lots of offspring
- parent often die - iteoparity
- several eggs/ offspring in repeated reproductive episodes
how long can some seeds remain viable for?
1600 years
what are ephemeral plants?
eg. desert plants- lifecycle usually <8 weeks reproduce in occasional years short lived usually 1 or more generations per year only during favourable periods
age. nx. Ix sx mx. Ixmx
0. 1000 1.0 0.5 0 0
1. 500 0.5 0.2 0 0
2. 100 0.1 0.5 4.0 0.5
a) what is nx?
b) what is Ix?
c) what is sx and how do you calculate?
d) what is mx and how do you calculate?
e) by calculating total of Ixmx what is this?
a) number at each stage
b) prop. of individuals that survive at each stage
c) age specific survival ( nx at 1/ nx at 0) then (nx at 2/nx at 1)
d) reproduction = number of female babies/ reproductive female
age specific fecundity
e) Ro= net reproductive rate
what does it mean for the pop. if net reproductive rate (Ro) is:
a) =1
b) <1
c) >1
a) stable, females replaced perfectly
b) fewer females–> pop decline
c) pop increase
what is a super spreader and a super shedder?
super spreader: males lots of contact to spread disease
super shedder: produces lots of infection
what is the Ro of each of these diseases and put them in order of least to most contagious?
- HIV
- mumps
- ebola
- SARS
- measles
- Hepatisis C
Hepatisis C =2 ebola =2 HIV =4 SARS =4 mumps =10 measles =18
what is the generation time and whats the equation for it?
average time between birth of individual and birth of offspring
G = total [( x) X (Ix) X (mx)] / Ro
if lots of energy is invested into reproduction one year what happens the next year?
there will be less the next year due to the energetic costs of caring for offspring
how do you work out fertility?
no. produced by one class X survival to age class
a) how do you work out Fx?
b) what is the Leslie matrix?
c) what are 3 +ves of it?
a) sxmx
b) F0 F1 F2 F3
S0 0 0 0
0 S1 0 0
0 0 S2 0
c) - derive finite pop change rate (λ) and distribution
- can identify main age specific vital rates affecting abundance and age structure
- modify analyses to include density
what is λ? and what happens in each scenario? a) λ<1 b) λ>1 c) λ=1
pop growth rate
a) pop decline
b) pop increase
c) stable pop
for exponential growth, how do we work out the change in pop size during time interval?
births in time interval - deaths in time interval
r= b-d
what was the exponential growth see in sea otters?
by 1911 decrease to few thousand
re introduced 1960s
30 fold increase in 30 years to 100,000
what is the most common determinant of K?
energy/ resource limitation
what are the 3 rules of population limitation?
- K of a habitat is the max stable population size that can be supported over time
- as density increases, per capita resource declines
- as density increases and per capita resource decline, births decline and deaths increase
what prevents unlimited pop growth?
negative feedback
resource limitation in crowded pop. can reduce reproduction
what is the logistic growth equation?
dN/dt = rN ( 1- N/K)
what 4 things can be generated by density dependence?
persistence, stability, equilibrium, individual coexistence
what are 3 assumptions of the logistics model?
- density dependence is linear
- pop. approaches carrying capacity smoothly
- K is constant
why may a pop overshoots carrying capacity in logistics model?
due to time delay before birth rate
can lead to oscillations around K
why may the growth rate be more than exponential for humans?
- altered environment capacity
- resources and agricultural productivity
- health care
what principle ideas did lotka and volterra produce?
competitive exclusion and niches
what is the completion exclusion principle?
no 2 species can share the same resource or occupy the same niche
a) what is a fundamental niche and what are some ecological/physiological limits and biotic limits?
b) when is there a realised niche?
a) intrinsic requirements of a species on its own
- abiotic/weather
- food/habitat
b) when theres a change to limits due to other species being present
what does each part of the equation mean?
dN/dt = (rN1) - (rN^2/ K) - (aN1N2)
a). b). c)
d) in this equation what does it mean if the lines cross and if they don’t cross?
a) exponential growth
b) intraspecific/ -ve feedback/ density dependence
c) interspecific/-ve feedback/ effect of N2 on you (N1)
d) cross= coexistance
don’t cross= competitive exclusion
when interspecific competition is weak what can occur?
coexistence
intra»inter
what is scramble competition and what are the 2 types?
consumptive
- exploitation (depleting resources)
- preemptive (using space)
what is contest competition and what are the 4 types?
interference
- overgrowth (grows over another depriving it of light)
- chemical (toxin production)
- territorial (defending space)
- encounter (interactions directly over a specific resource)
in the bedstraw experiment in which conditions did the G.saxtile and G.sylvestre thrive in?
saxtille: acidic
sylvestre: calcareous
in detail for what 5 reasons is predation important?
- ecology
- structure and dynamics of communities - evolution
- morphology, physiology, behaviour - agriculture
- pest control - conservation
- predator control - biodiversity
- richness, eveness, diversity
give 6 predator strategies
- mobility
- timing
- space
- camouflage
- morphology
- trickery
give 5 prey defences?
- camouflage/ crypts
- inducible/ systemic defence
- habitat shifts
- aposematic colouration
- batesian and mullerian mimicry
whats the difference between batesian and mullerian mimicry and which is parallel development and which is coevolution?
- batesian: (coevolution) unpalatbale mimic harmful model - mullerian (parallel) 2 unpalatable individuals mimic each other
what are the 3 stages to the optimisation theory?
- objective: maximise or minimise?
- currency: unit to maximise (energy)
- constraints
what would be the optimisation theory for predicting diet choice?
objective: maximise profitability
currency: profitability
constraints: search and handling time
what is the contingency model of foraging and what is the equation?
- choose most profitable, ignoring search costs
- add new items until profit is less than average cost of search and handling time
profit of new item>= cost of ignoring 2 and searching for another
is the most profitable choice them most abundant?
no
a) what is the logistic consumption/ growth model?
b) why is rate low when prey density low?
c) why does consumption rate plateau?
a) -ve feedbck
rate increases then decreases
b) can’t find them
c) satiation
what % of energy is transferred from one trophic level to another?
10%
a) what does keystone predation do to diversity?
b) what does generalist predation do to diversity?
a) increases
b) decreases
what is the trophic cascade with predator at the top?
predator –(-)–> prey –(-)–> resource
resource –(+)–>predator
what are the 3 types of parasites?
microparasites, macroparasites, parasitoids
what are micro parasites + examples?
- multiply inside host
- malaria (protist)
- influenza, hepatitis (viruses)
- ringworm (fungi)
what are macro parasites + examples?
- dont multiply inside host
- reproduction still occurs
- ticks (arthropod)
- roundworm (nematode)
what are parasitoids + examples?
- larvae injected into/laid upon host feeding on body of another arthropod, killing it
- obligate killers
whats the difference between vertical and horizontal transmission?
vertical: between generation from parent to offspring
horizontal: within 1 generation between unrelated individuals
list the 3 main transition types for horizontal transmission
- ordinarily infectious disease (OIDs)
- sexually transmitted diseases (STDs)
- vector transmitted diseases
what is an ordinary infectious disease and what does the graph look like?
straight diagonal line- directly proportional
-ve feedback
random contact
what are sexually transmitted diseases and what is the graph like?
number of contacts saturates/plateaus
random encounters of limited frequency
unlikely to regulate at high density
extinction may occur at low density
what are vector transmitted diseases/graph?
number of contacts first increases with density
at high density if vector pop fixed then number falls per host
what is SIR?
susceptible infected resistant
in terms of disease what does Ro tell us and how do you work it out?
tells us average number of people who will catch a disease from one contagious person
= transmission rate/ recovery rate
what is the parasite cycle in grouse and what do the parasites do to the bird?
parasites in high levels so decreases reproduction and increases mortality and steal energy from the bird
- infected larvae ingested from heather
- adult worms in grouse caeca
- faeces
- eggs hatch and young embryo forms 2 moults
- encysted larvae
what is a mutualism?
where symbiosis is beneficial to both organisms involved
what is the fungal- root mutualism in micorrhizza?
sugar from photosynthetic trees to fungi
N and P to the tree from fungal decomposition
whats the difference between the 2 types of micorrhizza:
ectomycorrhiza, endomycorrihiza?
ecto: non penetrative, 10% plant families, birch, oak, pine
endo: penetrative into root cell. 85% plants
whats the difference in terms of pollination for bees and wild insects?
bees:more pollen, less fruit, bees ineffective
wild pollinators: less pollen, more fruit,
for the patch residence:
- if the distance is bigger how much time is spent there?
- in a high quality patch how much time will be spent there?
- will spend more time in a patch
- spend less time
for the patch residence what does the tangent do?
maximises ratio between resource intake and time spent foraging
what 5 things does foraging behaviour underpin?
what do these drive?
- competition
- predation
- mutualism
- disease
- structure and complexity of communities
drive patterns of abundance and distribution
within species richness what are the 3 types of diversity?
α diversity- within sites
γ diversity- in all sites
β diversity - across sites (turnover of species)
within β diversity what is the jacquard coefficient what does it compare/what is the equation?
a/ (a + b+ c) compare community composition a= species in both sites b= site 1 species not 2 c= site 2 species not 1
if sites are nested what can we predict?
predict identities of species absent in smaller sites
are S.A.R.S linear?
non linear
in species area relationship what is the equation for finding the number of species?
S= cA^z
c(intercept)
A(area)
z(exponent)
what happens to species richness with a tenfold increase in area?
species richness doubles
in the α diversity survey of coniferous woodland and pinion juniper woodland on mountain tops what happens when a 3c increase in temp?
- too warm for coniferous forests
- p-j more on mountain tops
- habitat type altitudinal shift
- reduction in habitat area
- boreal mammal communities declined
what are 2 assumptions of the response of communities to habitat change?
- no dispersal across valleys to colonise new sites
- distribution and abundance declines in prop. to habitat loss
do larger or smaller species harbour common or rare species?
large: common and rare
small: common
what are the 3 factors for a simple null model?
- pattern of nestedness lost
- same species richness per island
- species in random subsets
do mainland or islands have a shallower slope?
what does mainland SAR provide?
mainland
approximate predictor of max diversity of islands
as distance of island from mainland increases what happens to saturation?
distance increases, saturation decreases
a) what does saturation by isolation suggest?
b) as isolation increases what happens to alpha diversity?
a) that area isn’t the only factor for alpha diversity
b) declines
what does the island biogeography theory predict and who suggested it?
Mac Arthur and Wilson
predicts species richness on islands
how are island communities formed?
species arrive (immigration) species persist ( extinction)
what is the immigration rate like on an island with a) no species and b) many species
a) high immigration rate, unrepresented individuals
b) species usually already present on islands, immigration rates low
what is the extinction rate like on an island with a) no species and b) many species
a) can be no extinction, low rate
b) some local extinction, increased competition suppresses pop sizes so extinction rate increases
for extinction and immigration equilibrium model what are the 2 key predictions?
- once equilibrium reached species present usually constant through time
- new species arrive by immigration and replace/ drive to extinction resident species
when was the Krakatoa explosion and what happened?
1883
flora and fauna exterminated
rapid increase in returning species then rate slows
decline in immigration as no. of species increases
what is the immigration rate like on isolated islands?
colonisers have less chance of reaching island
immigration rates reduced
equilibrium species richness declines with isolation
what is the extinction rate like for isolated islands?
mainland pop can restock pop of island species
reduced extinction rate
equilibrium species richness increases
what is the effect on immigration for a large area/island?
bigger target for colonising species
immigration rate increases
what is the effect in extinction for a large island/area?
large islands can support larger pop