Exam 1

• What are the characteristics of a good hypothesis? 

  A good hypothesis provides predictions, must be testable, and must be falsifiable.
• What is a null hypothesis?

  Hypothesis formulated as a statement of no cause-and-effect, it is statistically testable and could be rejected in favor of an alternative hypothesis.
• What is the role of falsifiability in hypothesis testing?

  to reject or falsify the hypothesis.
• What are some factors that can drive evolution?

  Mutations, gene flow, genetic drift.
• Define the founder effect

  establishment of a new population from a larger population
• Bottleneck effect

  the large reduction of population size followed by an expansion.
• define...

  Directional: Extremes at one end are selected against

  Stabilizing: A single phenotype is favored and selected so like the middle is selected

  Disruptive: Extreme phenotypes are selected: two peaks at extremes with dip in middle.
• What is the biological species concept?

  groups of individuals that are actually or potentially capable of breeding to produce viable offspring.
• What is Liebig’s Law of the Minimum?

  Rate of biological process limited by the resource that is least available relative to requirements.
• What is Shelford’s Law of Tolerance?

  Distribution is limited by environmental factors for which organism has the narrowest tolerance range.
• Define diffusion, jump dispersal and secular dispersal

  Diffusion: gradual movement across hospitable terrain

  Jump dispersal: movement across large (usually inhospitable) distances

  Secular dispersal: diffusion over significant time, evolution occurs, migrants diverge genetically from ancestral source.
• What predictions does the ideal free distribution model make about how organisms are distributed across habitats?

  Pops increase in ‘best’ habitat, resources decline and habitat quality becomes equal to lesser habitat.
• What is the ideal despotic distribution model?

  territorial, aggressive individuals occupy best habitats, subordinates forced into lesser habitats.
• What is a population? What is a modular organism

  Population: group of individuals of the same species that live in the same place and time

  Modular organisms: consist of multiple interconnected modules so it becomes diff to determine whether a module should be considered an individual or part of a larger pop.
• What’s the difference between absolute density and relative density?

  Absolute density: actual # of individuals per unit area or volume

  Relative density: Density relative to some control or reference
• Review some of the methods discussed for measuring density.

  - Quadrats: Defined sample area, often used for 2D assessment, used for vegetation of benthic communities.

  - Transects: Path along which organisms are counted/measured. Assumes all organisms at the observation point or on a line are detected and observed before they flee.

  o Point: The observer stands in one spot, and records all species,

  o Line: records along the specified line.

  - Mark-recapture: Method to estimate total pop size. Capture individuals, mark, release and wait a reasonable time before recapturing and counting # marked.
• What is the Mark-recapture formula?

  m2/c2=m1/T
• What is the total population size formula?

  T=(m1*c2)/m2
• What does m1, m2, and c2 stand for?

  m1= marked animals in 1st sample

  m2 = marked animals in 2nd sample

  c2= total caught in 2nd sample
• What are the assumptions that must be met to accurately estimate population size with mark-recapture.

  - Initial capture samples pop randomly (not biased)

  - Marking doesn’t affect behavior, mortality

  - Marked and unmarked animals have equal capture efficiency

  - The time interval is short enough

  - Time interval is long enough to allow dispersion

  - Dispersion is random
• What is the difference between density and dispersion?

  - Density: # of individuals in population per unit area (or volume)

  - Dispersion: pattern of spacing among individuals in a population
• How do you find lx, dx, qx, bx, lxbx, and xlxbx on a life table?

  lx = number alive at age x(nx)/portion surviving at start (n0)

  dx = nx - nx+1

  qx = dx/nx

  bx = births/nx

  lxbx = lx*bx

  xlxbx= x(lx*bx)
• What is R0, generation time, Nt (discrete), Nt (continuous), and r

  R0 = Σ lx bx

  G = Σ x(lx bx)/R0

  r = ln(R0)/G

  Discrete, non-overlapping: Nt = N0R^t

  Continuous, overlapping: Nt = N0e^rt