1Under what situations do populations grow GEOmetrically? Give hyp. examples.
Equation = Nt = N0*λ^t
Non-overlapping generations, discrete reproductive bouts. Population growth is not limited by resources, predation, etc. Example = Waterhemp, repoduces annually and invades soybean fields.
2Under what situations do populations grow EXPOnentially? Give hyp. examples.
Equation = Nt = N0*e^rt
Overlapping generations, continuous growth. Population growth is not limited by resources. Example = Soybean aphid, ~15 generations per summer and have complex life cycles
3Under what situations do populations grow LOGistically? Give hyp. examples.
Equation = dN/dt = rN(1-N/K)
Resources limit population growth. Continuous growth, generations overlap. Example = Yeast, pop grows quicky but at higher densities growth slows and levels.
4How do you use the Exponential Growth Equation to predict future pop. size and calculating pop. doubling time?
Nt=N0*e^rt and doubleing time equation = t = 0.693
5What values of r indicate GROWING?
R>0
6What values of r indicate DECLINING?
R<0
7What values of r indicate a STABLE POP.?
R=0
8Define Density Dependent Factors. How do they influence population growth?
The stregnth of effect depends on population density. Examples = food availability, spread of disease, predation, etc. Would be considered Biotic. Represented in the logictic equation. Can regulate population size in relation to carrying capacity, factors push more as density increases and ultimately limits carrying capacity.
9Define Density Independent Factors. How do they influence population growth?
The strength of effect is independent of population density. Examples = weather, fire, etc. Would be considered abiotic
10Describe Source-sink Population Dynamics. What implications does it have for conservation management?
Small populations are continuakky augmented or rescued by immigrants from large growing populations. One way movement patches are defined sources or sinks. Relies on source, maintaining source populations.
11Describe Metapopulation Dynamics. What implications does it have for conservation management? What factors determine the proportion of patches occupied?
Composed of sub-populations distributed amoung spatially isolated pathes but connected by echange of individuals among patches. No inherent source/sink, all moving, more dynamic. Maintain interconnectedness of sites if one site goes extinct there are others. Patch colonization rate and extinction rate are factors.
12Define Environmental Stochasticity
Unperdictable fluctuation in environment
13Define Demographic Stochasticity
Random fluctuations in births and deaths, important in small populations.
14Define Allee Effects
Decline in population growth at low densities, small population size can lead to declines in population growth rate (inverse density dependance).
15Define Delayed Density Dependence/Deterministic Chaos
Dely or lag in effect that density has on population growth. Log. equation can be modified to include time lags in effects of density dependance on pop growth
16Define niche of an organism
Unique role a species plays in it's ecosystem, encompassing it;s possition,function, and interations with bot biotic and abiotic aspects of its environment
17Niche expressed by Grinnell
Abiotic conditions that limit species distribution
18Niche expressed by Elton
Environment & species functional role (trophic level, "job")
19Niche expressed by Hutchinson
"n-dimensional hyervolume" of environmental factors
20Fundamental niche
all environmental conditions where a species is able to live, Mosquitos = higher temperature and humiditiy
21Realized niche
Where the species actually lives
22Describe Gause's competitive exclusion principle
No teo species can coexist if they occuoy the same niche
23Describe Removal and Exclusion experiments
Experimental removal to quantify competitive effects. Example = Ants and rodents, both present, removed rodents, removed ants, removed both
24Common Garden experiments
Help seperate environmental effects from species interation effects, remove 2 species and place in controlled environment, 2 bedstraw species, grown on peat and limestone soil
25Three reasons why coexistence can occur between two species with seemingly very similar niches and provide hypothetical examples to illustrate.
1. Niches differ. Example = plethodon salamanders- = differences in jaw closing rate/strength and prey sizes
2. Neutral theory of biodiversity: species randomly distributed over space and time, not structured by competition or other interactions.
3. Other ecological interations may influence population size and weaken impact of competion. Example = sea urchins as a keystone predator
26Define Character Displacement
When two species compete, natural selection may reduce the strength of the competion by changing some characteristic of one or both species.
27Define intraspecific competion
With others of the same species, in the logistic growth equation
28Define interspecific competion
Between different species
29Define Direct Competion
Produced when one individual or species directly impacts another without the interaction being mediated by or transmitted through thrid party.
30Define Indirect competion
When an interation between two species or individuals is mediated by a third individual/species or by another agent, such as a resource
31define resource competion
occurs when individuals compete indirectly by consuming a shared resource. depleation of water, nutrients
32Define interference competion
occurs when competing individuals (normally same species) directly interacts in an attempt to reduce the others access to resources. allelopathy, preemption
33Define Allelopathy
Plants release poisons that prevents growth of other species
34Territoriality
Animals defending territory agsindt possible competion
35Preemption
Get there first, claim area, interered with ability of other individuals to take spot.