Ecology and Evolution Exam 2 Vocabulary

BIOL 2100

Life history strategy

A schedule of lx and bx that maximized offspring production and survival in a particular environment (often maximized r)

Type I survivorship Curve

Good juvenile survivorship, poor adult survivorship (ex. humans)

Type II survivorship curve

Chances of survivorship remains the same throughout their lifespan (not as common)

Type III survivorship curve

Poor juvenile survivorship but good adult survivorship

semelparity

Reproduce one time (“boom and bust”) (ex. salmon)

iteroparity

reproduce multiple times within a lifespan (ex. humans)

How to increase r in a life table?

1. reduce age at first reproduction

2. increase litter size

3. increase in number of litters

   1. increase survivorship of juvenile and reproductive age classes

Loles’ Law

r(iteroparous) ~ r(semelparous + 1 more offspring/individual)

bet-hedging strategy

A survival strategy that involves producing offspring with varying levels of resilience/risk in an uncertain environment. Ensures a degree of success even if some individual outcomes are unfavorable. (ex. diversified germination in plant seeds, some sprout in 1 year, some in 10, some in 50 in case of unfavorable conditions causing 1 group to die)

R-selection

R-selected species produce many offspring with minimal parental care to quickly exploit available resources.

k-selection

K-selected species are born into a crowded, resource limited environment. Produce fewer offspring but invest heavily in each, ensuring a higher probability of survival to adulthood

Exploitation competition

Indirect, shared resourcesI

Interference competition

direct, behavior, territoriality. Affect exploitation efficiency of competitor. (ex. alleleopathy)

Pre-emptive competition

Competition for space as a resource (ex. plants, mairine invertebrates). Blend of exploitation and interference competition

Lotka-Volterra Competition equations (L-V)

alpha

effect of N2 on population growth rate of N1, measured in units of N1. Measures interspecific vs intraspecific interactions

meaning of alpha = 1

interspecific competition = intraspecific competition

meaning of alpha > 1

N2 has a greater effect on N1 than N1 has on N1.

meaning of alpha = 0?

no interspecific effect

meaning of alpha < 0?

helping population growth, indicates symbiotic relationship or prey outcome

Meaning of alpha < 1

Intraspecific competition (N1) has a greater effect on N1 than interspecific competition (N2) does.

isocline

A combination of abundances of N1 and N2 such that dN1/dt = 0

Assumptions of L-V model

1. No Immigration of Emmigration

2. No age/size/genetic structure

3. No time lags

   1. Constant K1, K2, alpha, beta

Case 1 L-V model

Species 1 wins

Case 2 L-V model

Species 2 wins

Case 3 L-V model

stable coexistence

Case 4 L-V model

Unstable coexistence

rationale for preserving species

1. moral/aesthetic arguments

2. Natural products

   1. ecosystem services (climate, flooding erosion control, pollinator services)

Niche (Hutchinson definition)

An n-dimensional hypervolume that defines a set of conditions for which dN/dt > 0

Funamental niche

Species living alone in an environment

Realized niche

Species in presence of other species (took a bite out of cookie)

Charater displacement

Divergence in body size or morphology of competitors living in sympatry

In L-V model Case 3 superimposed with an empirical yield curve: would you over or under yield? Would you plant monoculture or polyculture?

Overyielding (dynamic equilibrium is above the yield curve), plant polyculture

In L-V model Case 3 superimposed with an empirical yield curve: would you over or under yield? Would you plant monoculture or polyculture?

Under yielding (dynamic equilibrium is under the yield curve), plant monoculture

Environmental niche space graph

Paradox of the plankton (Gause)

Refers to the observation that, contrasting the competitive exclusion principle that suggests only one species can dominate a single limiting resource, many species of plankton coexist in well-mixed aquatic environments. 

rescue effect

Immigration to a local population prevents extinction

sink population

an ecological population living in a low-quality habitat that cannot sustain itself through local reproduction alone and relies on continuous immigration from a high-quality “source” habitat for its persistence (negative growth rate)

Source population

Has a positive growth rate and exports individuals to the sink population (negative growth rate)

Sympatry

Situation where different species/populations coexist and live in the same geographical area

Allopatry

State where 2 populations are in different geographic locations, preventing gene flow

Ecological assortment

Extinctions lead to the separation of species along niche areas

L-V predation model examples

Predation, parasitism, seed consumption, herbivory

Alpha (L-V Predator-Prey model)

Capture efficiency

How efficiently P kills V

Beta (L-V Predator-Prey model)

Conversion efficiency

Ability of P to convert V into offspring of P

dV/dt (equation, when is it equal to 0?)

rV - (alpha)VP

when p(hat) = r/alpha

dP/dt (equation, when is it equal to 0?)

(beta)VP - qP

when v(hat) = q/beta

Period of a cycle = 

2pi/ sqrt(rq)

Assumptions of L-V Predator-Prey model

1. No I or E, No age, size, genetic structure, no time lags

2. No carrying capacity for V

3. P is a specialist on V

4. P and V encounter one another randomly in a homogenous environment

5. Individual predators are insatiable