# Ecology 320 Exam 2

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- What does the X colomn stand for in life tables?
- Age Class
- What does the Nx column stand for in life tables?
- Number of survivors at the beginning of each age class.
- What does Ix stand for in the life tables? What axis is it on a graph?
- Proportion o forganisms surviving to start age class interval, x Formula: Nx/Ni Normally plotted on the y-axis.
- Describe the Survivorship I curve
- organisms live out their full physiological lifetime Ex: humans
- Describe the Survivorship II curve
- rate of mortality is fairly constant across age groups least common type
- Describe the Survivorship III curve
- organisms experience high mortality early in life Ex: tabpoles
- What does dx stand for on a life properties table?
- Number of organisms dying during age interval x to x+1
- What is dx (of the life properties table) expressed as?
- A proportion of initial population Formula: Ni/dx
- What does the Qx (from the life properties table) stand for?
- Gives the age specific morality rate Fromula: dx/Nx
- What is Lx from the life properties table?
- Average number of total years lived during age interval x to x+1 Formula: (Nx+N(x+1))/2
- Wat does Tx (from the life properties table) stand for?
- It shows the numbers of years left to live T1 = sum of Lx Tx = T(x-1)-L(x-1)
- What does ex (in the life properties table) stand for?
- Average life expectancy for individuals at the start of an age interval, x. Formula: Tx/Nx
- What is a cohort or dynamic life table?
- constructed by following a cohort of individuals, a group of individuals born within a given time span
- What is a Time-specific, or static, life table?
- sampling the population and obtaining a distribution of age classes during a specific period of time Assumes: 1) Each age class is sampled in proportion to its number in the population 2) Birth and death rates are constant 3) Population is stationary
- What is a dynamic-composite?
- similar to cohort approach, but it constructs a cohort from a composite of a number of individuals sampled over a period of years rather than just one birth period
- What is a Fecundity table?
- It involves the reproductive rates of a population.
- What is mx (in a life properties table)?
- It is the average number of daughters produced by a mother of a given age (x)
- How is the net reproductive rate calculated? What is the symbol?
- Symbol: Ro Formula: sum of (lx*mx) lx = proportion of oganisms surviving to start age class interval, x mx = average # of daughters prduced by mother of given age (x)
- What it Ro?
- It is the average number of female offspring produced during the lifetime of a newborn female. Formula: sum of (lx*mx)
- What is Sx (in the life properties table)?
- It is the survival rate. Formula: 1-qx
- What is necessary to construct an age structure over time?
- 1) Initial age structure of population 2)Age specific survivor rate 3) Age specific birth rate Result: ability to predict the population for any time in the future
- What is the Finite Multiplication Rule?
- EDIT ME!!
- What is age distribution?
- Overtime, this begins to converge with a lot in the younger ages...LOOK UP BOOK DEFINITION
- What is stable age distribution?
- constant proportion of individuals in the various age classes of a population - occurs in years 7 & 8 - can occur while population is still growing
- What is stationary age distribution?
- A special form of stable age distribution in which the population has reached a constant size with birth and death rates equal. - the lambda is 1
- What is the Geometric Population Growth?
- - plotted to see what the density looks like over time - stable age distribution; constant lambda - Needed: initial # of population & lambda
- What is the finite multiplication rate for?
- It can be used to estimate a continuous or instantaeous per capita rate of growth
- What is Intrinsic Rate of Increase?
- it is the continous or instantaneous per capita rate of growth, r
- What is the equation for the Intrinsic Rate of Increase?
- r = ln(lambda)
- How do you go from discrete to continuous equations?
- r = ln(lambda) e^r = lambda Nt = N0 * e^(rt) - Graph the Nt equation to create an exponential curve with no discrete points
- What is the slope for an exponential model of population growth?
- dN/dt = rNt For which Nt = N0 * e^(rt) is the integrated form
- What is K?
- K is the carrying capacity or population density that can be sustained given the availability of resources in the environment.
- What is the rate of population growth equation with K included?
- dN/dt = (rN)((K-N)/K)
- What are the relationships between N and K?
- - When the population size (N) is near zero, (K-N)/K is close to 1.0 and the population grows exponentially - as N approaches K, (K-N)/K approaches 0.0 and the population ceases to grow
- What occurs from predatory?
- - Effects on predator and prey populations - Functional and numerical response of predators - Prey responses
- What occurs from herbivory?
- Ecological evolutionary responses
- What are "true" predators?
- They are lethal - cause death.
- What are parasitoids? Are they lethal?
- Yes, they are ultimately lethal. They survive on prey, until prey dies and parasitoids moves onto another prey
- What are parasites? Are they lethal?
- They are (sub)lethal. Their objective is not to kill prey because it is needed to survive.
- What are grazers? Are they lethal?
- They are generally not lethal. They are seed predators.
- Each predator prey relationship changes the others population. What is the equation for the rate of change for a prey population?
- It is the (birth rate) - (death rate) dNprey/dt = rNprey - C*Npred*Nprey - C is the predation rate; efficiency of search and attack - Nprey = prey population density - Npred = predator population density r = intrinsic rate of growth
- What is the prey growth rate equal to?
- Prey birth rate
- What does C stand for?
- It is the predation rate. - how efficienct the predators are at searching for the prey - how efficient the predators are at attacking for the prey
- What is predation rate the same as? What is the corresponding assumption?
- It is the same as death rate. Assumption: all deaths are caused by the predators.
- Each predator prey relationship changes the others population. What is the rate of change of a predator population?
- dNpred/dt = B(C*Npred*Nprey)-D*Npred - Nprey = prey pop. density -Npred = pred. pop. density - D = death rate of predators - B = efficiency of pred. converting food consumed into offspring - C = efficiency of search and attack
- In the rate of change for a predator, what does B stand for?
- (number of prey killed) * (efficiency of predators)
- How do you calculate the zero net growth isoclines?
- We want to set dN/dt to zero to show no growth Follow equation algebraically (for rate of change in prey/pred. pop. density) When # of predators = r/C, the prey is not growing When # of prey = D/(B*C) the predator population is not changing
- What axis is the # of prey? # of predators?
- # of prey is on the x-axis # of predators is on the y-axis
- What occurs to the prey population when it is above the (r/C) line? when it is below?
- Above: prey population is declining Below: prey population is increasing
- What happens to the predator population when it is to the left of the (D/BC) line? when it is to the right?
- Left: decreasing predator population Right: increasing predator population.
- When there are a lot of predators, what are the effects?
- 1) the prey population declines 2) the predator population declines
- What happens when the predator numbers decrease?
- 1) the prey numbers increase
- What did Gause use for his experiments? What was the outcome?
- His experiments used protoza. FINISH!!
- What is functional response? What is the equation?
- Implies that the individual predator consumes more prey as the prey population increases. C*NPred*Nprey
- What is numerical response? What is the equation?
- increased consumption of prey results in an increase in predator reproduction B (C Npred NPrey)
- Describe the type 1 functional response.
- It is linear because the predator always eats the same amount.
- Describe the type 2 functional response.
- # of prey killed increases, and then saturates - might imply that if prey increases, then why donâ€™t predators increase? There is probably another limiting factor to the predator
- Describe the type 3 functional response.
- # of prey taken is low, maybe has to do with refugia, it then increases, and then the Type II saturation occurs - low prey densities = low prey kills - high prey densities = saturating prey kills
- What is lag time?
- It is the time it takes for the predator population to respond to the prey population.
- What are some defense mechanisms in plants?
- Structural defences (like thorns and tough decomposition) Chemical defenses
- When are defenses seen in plants?
- When there is a strong plant/herbivore interaction and slow rate of growth
- How do grazers decide where to eat?
- It depends on the nutritional content. They want to increase their nitrogen (N) uptake
- What are prey coevolution responses?
- Defenses: chemical and morphological Mimicry Satiation - plant/seed production -huge seed production may be a response to seed herbivory Behavioral
- Please draw the Population Interaction table.
- Competition: both negative Predation: +/- Parasitism: +/- Amensalism: -/0 Commensalism: +/0 Mutualism: +/+ Neutral: 0/0
- What are the 2 assumptions of interspecific competition?
- The 2 species coexist in time and space Shared resource is limiting resource
- What is the outcome when plants are grown alone vs. together?
- The competition changes the biomass...what else??
- What is partitioning competition?
- LOOK UP IN BOOK!
- What is the logistic equation?
- dN1/dt = rN1((K1-N1)/K1)
- Each species ________ the availability of resources for the other. It ______ the population size.
- a) decreases b) limits
- What are the types of individuals?
- genets (sexual), ramets (asexual), clone (group of ramets from one genet)
- What is a metapopulation?
- Separated populations of a species interconnected by dispersal of individuals among habitat patches in heterogeneous landscape
- What are 3 ways of dispersion?
- Uniform (intraspecific competition) Random (uniform environment) Clumped (habitat, reproduction)
- Dispersion affects our ability to determine _____ through sampling.
- density
- What is community?
- naturally occurring and interacting assemblage of species
- What influence the community?
- abiotic disturbance, climate, species interactions, resource availability, species effects
- What is the dominance-diversity curve?
- It is the plotting of the most abundant to the least abundant species, creating a decreasing slope.
- What are Clement's (1916) views?
- - competition yields distinct cut-offs - discrete, repeatable associations - species have co-evolved - functions as a unit
- What are Gleason's (1926) views?
- - diffuse boundaries between species - species respond independently to environmental tolerances - associations due to similar requirements - chance plays a role
- What is species richness?
- number of species
- What is species evenness?
- Number of individuals in a species
- What is the "super-organism" view?
- Clement's view
- What is the "individualistic" view?
- Gleason's view
- Who is Whittacre and what did he do?
- He bridged the gap between Clement and Gleason.
- How do we describe the structure of a community?
- Physical -Vertical - Horizontal Biological - species composition - numbers, mass, importance - diversity
- What fators influence community structure?
- - competition - predation - other interactions - dispersal, resource requirements
- Describe the aquatic stratification.
- Temperature: decreases with depth Light: decreases with depth Nutrients: increases with depth
- What are terrestrial zones?
- It is the vertical structure of light, made up by plants, effecting plant diversity
- How does the vertical structure influence animal diversity?
- The greater the number of layers, the greater the number of different species that can be supported.
- What are patchwork landscapes?
- Changes in: Slope, Aspect, Soil nutrients, Soil moisture, Light
- What are two types of patchwork landscapes?
- Edges: abrupt changes in landscape Ecotones: gradual transition between communities, where physical factors are not changing so abruptly, meaning animal types are not changing abruptly - tend to see higher diversity b/c they are a mix of communities on either side
- Why do edges/ecotones have increased biodiversity?
- Because this is where two communities meet
- What is zoneation?
- spatial changes in community structure
- Competition may influence:
- the presence, absence or dominance of a species (organization)
- What effect does predation have?
- It prevents dominating species
- What is the cascading effect?
- predator lowers the prey population, so the preyâ€™s food population will increase
- What are keystone species?
- The are vital to an ecosystem. - many prey species would die out and biodiversity will decrease