EcologyQuiz4

• R₀: net reproductive rate
• x: age interval
• l_x: percent population surviving until age x (survival rate)
• m_x: average # offspring produced by each individual in each age category (birth rate)
• Create a table of this data and sum R₀ to determine the final #offspring/individual

• Life stages (larva and adult? male/female?)
• Age at maturity
• Age at 1st reproductive event
• # of reproductive events
• # and size of offspring
• Post-reproductive lifespan

• Fish that produced more eggs produced smaller eggs
• Populations with many small eggs had fewer allelic differences than pops from few large eggs
• Larvae from lg eggs: hatch earlier, feed earlier, do not drift as far, & do not disperse great distances

• Graminoids: Grass and grass-like plants.
• Forbs: Herbaceous, non-graminoids.
• Woody Plants: Woody thickening of tissues.
• Climbers: Climbing plants and vines

• Unassisted: No specialized structures.
• Adhesion: Hooks, spines, or barbs.
• Wind: wings, hair, (resistance structures).
• Ant: Oil surface coating (elaisome).
• Vertebrate: Fleshy coating (aril).
• Scatter-hoarded: Gathered, stored in caches

• Dispersal method influences seed size
• Plants producing a large amount of small seeds have an advantage in disturbed areas (weeds)
• Plants producing larger seeds produce less #
• Larger seeds produced larger/taller seedlings (more investment)

• Before: maintenance / growth
• After: maintenance / growth / reproduction
• Individuals delaying reproduction grow faster and to a larger size and have increased rates of reproduction when mature

If adult survival is low relative to juvenile, natural selection results in allocating more resources to reproduction

• r selection: (per capita rate of increase)
• Characteristic high population growth rate.
• Unpredictable Environments
• highest intrinsic rate of increase
• Numerous individuals rapidly produce
• –K selection: (carrying capacity)
• Characteristic efficient resource use.
• Predictable environments
• Most competitive ability
• Fewer, larger, individuals slowly reproduce

• Disturbance: destroys biomass
• Stress: external constraints limit productivity
• Four extremes: low low, low high, high low, and high high
• Competitive species dominate under low/low
• stress-tolerant species dominate under low disturbance high stress
• Annual grasses common under high disturbance low stress

• l_x: juvenile survivorship
• m_x: fecundity
• α_x: age of reproductive maturity
• Opportunistic: low lx & low mx & early αx
• Equilibrium:  high lx & low mx & late αx
• Periodic:  low lx & high mx & late αx
• Graphed on a 3 point graph to compare species

• λ: Geometric rate of increases (non overlapping generations)
• Nt+1: size at time in future
• Nt: size at time

• T: average generation time
• x: highest age in range
• lx: percent population surviving until age x (survival rate)
• mx: average # offspring produced by each individual in each age category (birth rate)
• Ro: Σl_xm_x

• r: per capita rate of increase (is population increasing or decreasing?)
• R0: net reproductive rate
• T: average generation time

• Nt: # individuals at time t
• N0: initial # individuals
• λ: geometric (nonoverlapping) rate of increase
• t: # time intervals/generations

• dN/dT: change in population over time
• r_max: population growth rate (maximum possible)
• N: population size
• For use in overlapping generations in an unlimited environment

• Nt: # individuals at time t
• No: initial # individuals
• e: base of natural log
• rmax: per capita rate of increase
• t: number of time intervals
• For use with overlapping generations

• For use with determining the effect of carrying capacity on overlapping generations population (logistic growth)
• r_max: maximum per capita increase
• N: # individuals
• K: carrying capacity
• N/K: environmental resistance
• too low will be not enough # individual to cause change
• too high will result in too many resources used

• Exploitative: differential ability to acquire resources
• Interference: Direct aggressive interaction between individuals
• Intraspecific: within one species
• Interspecific: between different species

• All of the possible environmental factors that influence growth, survival, and reproduction of a species.
• Hutchinson defines: n-dimensional hypervolume
• n- all factors a species needs to reproduce
• hypervolume-physical factors (not interactions)

• Fundamental: Hypervolume. Physical factors ONLY
• Theoretical max
• Realized: part "occupied", includes competition
• Real niche in nature

• Competitive exclusion: two species with identical niches cannot coexist indefinitely
• Better competitor eventually excludes other
• K determined by intraspecific competition when grown alone
• K determined by interspecific competition when growth together

• Degree of competition depends on niche overlap
• Character displacement causes directional selection for reduce nicheoverlap
• The beak depth in the finch example was more polarized when the two were on the same island!