APS 123 Flashcards
Define Community
All of the individuals of all the species that inhabit a particular geographic are
Organismal ecology concerns…
Behavioural, Physiological and Morphological traits and the mediate interactions:
among individuals, between species and with the environment
What is Semelparity?
Big bang reproduction
Large number of offspring are produced in a reproductive event, after which the individual dies.
What is Iteroparity?
When organisms produce several eggs/offspring during repeated reproductive strategies
What are Empheral species?
When desert plants and animals lie dormant.
Reproduce in the occasional years that the conditions are ok.
Most complete life cycles in less than 8 weeks.
What is Ro (little o)
the net reproduction rate
mean number of offspring per female over her life time
Elements of the Leslie Matrix
Sx, Mx, Fx
What do you get out of the Leslie Matrix
µ= population growth rate and the Stable age distribution
3 factors increasing population growth:
Increased survival
Increased reproduction
Decreased generation time
r=
intrinsic rate of increase
=births-deaths
What is density dependence?
(Negative Feedback)
When insufficient resources may reduce per capita birth rate.
Carrying capacity (K) determined by…
…energy/resource limitations
Eg availability of nesting sites, roosting sites
Sea otters as an example of exponential growth..
reintroduced in 1960s, 30 fold increase in 30 years
100,000 population
Carrying capacity (K) rules?
K of a habitat is the maximum stable population size that can be supported
As density increases, per capita resources decline…. bird rates decline and death rates increase.
Assumptions of the logistic model?
Density dependence is linear
Population approaches K smoothly
K is constant
r & K are…
… population level parameters (selection does not act on r&k)
Gause’s theory
Competition exclusion principle:
No 2 species can share the same resource
No 2 species can occupy the same niche
2 species cannot co exist when they have identical needs of a limited resource.
Competition theory
Population growth rate= exponential growth - intraspecific competition- interspecific competition
Equation for a line
Intraspecific=
Interspecific=
Intraspecific= intercept (K) Interspecific= gradient (adjustment of K) ALPHA
How to spot coexistence on a graph
Isoclines cross, when intra specific effects are stronger (K’s inside) than inter-specific effects.
(Exclusion=isoclines do not cross)
Categories of predation
Overgrowth, Chemical, Territorial, Encounter, Exploitation, Consumptive
2 types of competition
Scramble- exploitation, consumption
Contest- Interference, encounter
Define pre-emptive
Using space (depleting space)
MacArthurs 3 rules
No species can coexist unless they….
different resources
same resources in different places
same resources at different times
Components of the optimisation theory
Objective (to maximise profitability)
Currency (eg energy/time)
Constraints (Eg cant search whilst handling)
What is the contingency model of foraging?
Add items until the profit of new items is less than the average cost of searching and handling items currently in the diet.
What is the functional response?
How predator consumption varies with prey density. Type 1,2,3
Which type demonstrates negative feedback?
Type 3
Which one demonstrates inverse density dependence?
Type 2
Why might the consumption plateau? (type 2)
Satiation (full)`
-/-
Competition
+/-
Herbivory
+/+
Mutualism
+/0
Commensalism (one benefits/one not affected)
What are micro parasites?
Multiply in their definitive host
What are macro parasites ?
Do not multiply in their definitive hosts (Does not lead to an increase of parasites in host)
Examples of micro parasites?
Malaria (prototist)
Giardia (protozoan)
Viruses
Fungi
Examples of macro parasites?
Ticks (arthropod)
Roundworm
Schistosomes (flatworms)
What are parasitoids?
Larvae. Injected into or laid upon the host, feed exclusively on the body of another arthropod, eventually killing it. Obligate killers, but it takes time.
2 major types of transmission pathway?
Vertical transmission
Horizontal transmission
What is vertical transmission
Between generations from parents to offspring
What is horizontal transmission
Within one generation between unrelated individuals. Direct horizontal transmission.
What type of feedback from a host density dependent disease?
Negative feedback
Example of a mutualism
Mycorrhiza
A fungal root mutualism
Sugar from photosynthetic trees
N & P to tree from fungal decomposition
What is ectomycorrhiza
Non penetrative, 10% of plant families Birch, oak, pine and roses
Endoychcorrhiza
Penetrative into plant cells, ancient links, 85% of plants
What is the marginal value theorem? (Charnov)
An optimality model that usually describes the behaviour of an optimally foraging individual in a system where resources (often food) are located in discrete patches separated by areas with no resources.
What does the tangent represent?
It maximises the ration between resource intake and time spent foraging and travelling. Highest intake for time travelling and feeding.
How is diet breadth predicted?
Energy (E) Handling time (h) Encounter rates (µ)
What is alpha diversity?
Diversity within the sites
What is µ (gamma) diversity?
Species richness across all sites
What is B (beta) diversity?
Measures how different the samples are across the sites or the turnover of species.
How can you measure B diversity?
Jaccuard Coefficient (comparing community composition across 2 sites)
Jaccard Coefficient=
a+b+c
a=number of species found in both sites
b=number of species found in 1 but not 2
c=number of species found in 2 but not 1
What is nestedness?
How particular species fit within broader sites. (If sites are nested, we can predict the identities of species absent in smaller sites.
What do species area relationships show (SARs)
How many different species co occur in a given area?
How does species richness vary with area?
S (number of species) =
c A z
NON LINEAR
c=
A=
z=
c= y intercept (model parameter) A= area z= exponent (rise/run)
Observation evidence of SAR
Birds of the Californian channel islands.
Evidence of equilibrium
strong SAR, weak SIR
Experimental evidence of SAR
Defaunation of the florida keys (Simberloff and Wilson fumigated small mangrove islands)
High rate of increase. Then after 160 days it levels off. The near island hits equilibrium. The far away island is slightly lower. Colonisation curve is supported. Rate of turnover is low. Extinction is low. (some support of island biogeography theory)
Limitations of island biogeography equilibrium
Slopes of immigration &extinction not known.
Slopes may vary from island to island
Islands may not be in equilibrium
Imm and Ex rates vary within species
‘Rescue effect’ (high imm rates can save extinction)
ASSUMES NO SPECIATION ON ISLANDS
