Ecology Flashcards
What are the three cells and their intermediate points in order from the north pole to the equator?
Polar Cell
- polar front
Ferrel Cell
- subtropical high
Hadley Cell
- equatorial low
- Pressure ____ at high altitudes
- Warm air holds ____ water than cold air
decreased
more
What is the coriolis effect?
The Earth’s rotation causes moving bodies at its surface to be deflected, means that wind-driven ocean currents turn right in the Northern Hemisphere, and left in the Southern Hemisphere.
How do rain shadows occur?
Humid damp air rises from the ocean and begins ascending a mountain. The higher the air rises, the colder and less pressured it becomes and it begins to dispel it’s water. By the time passes the apex of the mountain and begins falling as it warms itself it draws up the moisture from the ground. Thus the ocean-facing side is very wet and the opposite side will be dried
Describe the continental effect
- a phenomenon that causes temperatures in inland areas to fluctuate more than temperatures near to large bodies of water.
- landmasses cool air faster than coastal areas, the costal areas see cooler summers and warmer winters,
- the more inland you get the more oppositely the effect self imposes
What are the characteristics of a tropical rainforest?
- High heat
- High precip.
- High biological diversity
What are the characteristics of a temperate forest?
- Medium heat
- Medium precip.
- High biological diversity
What are the characteristics of a boreal forest?
- Colder heat
- Medium precip.
- Medium biological diversity
What are the characteristics of a temperate grassland?
- Medium heat
- Low precip.
- Medium biological diversity
What are the characteristics of a tundra?
- Dry
- Cold
- Somewhat biologically diverse
What are the marine zones?
- Photic (100-200m depth)
- Aphotic (depth where light doesn’t reach)
- Benthic (along the bottom)
- Neritic (shallows)
- Intertidal zone (shore)
- Oceanic (length past the shallows)
Describe the Hutchinsonian niche
- Describes fundamental characteristics of any species: the global maximum population growth rate (rmax); the niche optimum (the environment for which rmax is reached); and the niche width (the environmental range for which intrinsic population growth rates are positive
Difference between fundamental and realised niche
- Realised niche: set of environmental conditions where the species occurs
- Fundamental niche: set of environmental conditions that the species can tolerate
What is the optimal foraging theory and it’s equation?
- Animals choose the most energy-efficient prey
- P = E / (S+C)
where P = net energy gained, E = energy gained from consuming prey, S = energy required to search for prey, C = energy required to digest the prey
What are the assumptions of the mark-recapture method and the equation?
- No immigration or emigration
- All members mix randomly
- Marks remain between samples (don’t fall or rub off)
- IC / Pop. size = RM / CR
What are the assumptions of the geometric growth model and what is the equation?
- Basic form of future population estimation
- Nt = (λ^t)(N0)
If λ > 1, population _____
If λ < 1, population _____
increases
decreases
What are the assumptions of the logistic growth model and it’s equation?
- Closed population
- Changes in abundance are concentrated around a discrete time (breeding season)
- Per capita birth and death rates are independent of the environment or pop. size
- All individuals are treated equally (age, sex ignored)
- ΔN/Δt = rN(1 - (N/K))
Where N = pop density
r = intrinsic per capita rate of increase (=ln(λ))
K = carrying capacity
Describe the exponential continuous-time population growth model?
- Species produce offspring randomly
- Closed population
- Per capita birth and death rates are independent of the environment or pop. size
- All individuals are treated equally (age, sex ignored)
- The continuous-time model is Nt = N0 e^rt , where Nt is the population abundance in the future, N0 is the population abundance in the first year, e is the natural logarithm, r is the instantaneous per capita rate of population growth (r = (B - D)/N0), and t is time. Produces exponential growth
Describe the logistic continuous time model for population growth?
- includes a carrying capacity term
- dN/dT = N(rmax)((K-N)/K)
dN/dt is the change in population density over time, N is the population density, rmax is the intrinsic rate of increase, and K is the carrying capacity. - The (K − N)/K slows population growth as the population density approaches K.
- The population density levels off at the carrying capacity, produces a stable equilibrium.
Describe discrete time population growth?
- Assumes the population can overshoot the carrying capacity and then quickly return to that value.
- Nt+1 = Nt + Nt(rdis)((K-Nt)/K)
where Nt+t is the population density at the next time step, Nt is the current population density, rdis is the maximum per capita rate of population change, and K is the carrying capacity.
- If rdis < 1, the equation leads to _____ _____
- if 1 < r < 2, it leads to ____ _____
- if 2 < rdis < 2.57, it leads to ___ ___ ___
- if rdis > 2.57, it leads to ____ ____
- monotonic damping
- damped oscillations
- stable limit cycles
- chaotic dynamics
Describe negative-density dependent
- Intraspecific resource competition
- Pops have higher per capita growth rate when small
- Is known the be wrong because the less individuals in a population, the less fit it is
Describe the allele effect
- Contrast to negative-density dependence
- Populations at low numbers are affected by a positive relationship between population growth rate and density
- Low density makes it harder to find mates, fend off predators, environmental conditioning