Exam 2 Flashcards
Population
A group of individuals of the same species living in a specific area at a given time.
Metapopulation
A collection of local populations of a species connected by occasional dispersal.
Clumped Dispersion
Individuals cluster together, often due to resource availability or social behavior.
Uniform Dispersion
Individuals are evenly spaced, often due to territorial behavior.
Random Dispersion
Individuals are distributed without a specific pattern
What factors affect clumped dispersion?
Resources and social behavior.
What factors affect uniform dispersion?
Territoriality and competition.
What factors affect random dispersion?
No specific factors
Population Age/Stage Pyramid
Shows the distribution of individuals by age or developmental stage, revealing the population’s age or stage structure.
What are some Density-Dependent Factors ?
Competition, Predation, and Disease
Density-Dependent Factors
Factors that become more intense as the population density increases, regulating population size.
Density-Independent Factors
Weather, Natural Disasters, and Habitat destruction affects populations regardless of density.
What drives Population Fluctuations?
Biotic (predation, competition) and abiotic (Climate, resource availability) Factors
Life Table
A summary of the age-specific mortality and reproductive rates in a population.
Demographic Stochasticity
Random variation in birth and death rates.
Environmental Stochasticity
Random environmental fluctuations
What factors influence population dynamics?
Demographic and Environmental Stochasticity
Type I Survivorship Curve
Low mortality early in life (eg humans)
Type II Survivorship Curve
Constant Mortality Rate (eg birds)
Type III survivorship curve
High mortality early in life (eg. trees)
Fecundity Table
Shows the age-specific birthrates for a population.
What is R0
It is the Net Reproductive Rate of Females
What is Net Reproductive Rate (R0)?
The average number of offspring produced by an individual in its lifetime.
Stable Age Distribution
The age structure a population approaches when its age-specific birth and death rates remain constant.
Exponential Growth
Continuous and unlimited
Geometric Growth
Discrete, non-overlapping generations.
Instantaneous Growth Rate
(r) the rate of population growth
Finite Growth Rate
(λ) Lambda The proportional change in population size between generations
Logistic Growth
Populations growth with limiting factors and a carrying capacity (K). Assumes sigmoid growth curve.
What Model explains Human Population Growth?
Logistic growth due to resource limitations and declining birth rates. The value of K is uncertain.
Demographic Transition Model
As societies develop, birth and death rates decline, leading to population stabilization. Age-structure pyramids reflect this transition.
Intraspecific Competition
Competition among individuals of the same species.
What can Intraspecific competition lead to?
Reduced growth, fecundity, and survival.
r-strategists
High reproductive rates and adapt to unstable environments.
k-strategists
lower reproductive rates and are adapted to stable environments.
Interspecific Competition
Competition between different species for shared resources.
Lotka-Volterra Equations for Competition
Describes the interactions and outcomes of competition between two species.
What are the four outcomes of competition?
Competitive exclusion, coexistence, resource partitioning, and character displacement.
Ecological Niche
The role and position a species has in its environment.
Competitive exclusion
When two species have identical niches can lead to elimination of one species.
Predation
The consumption of one organism by another.
Forms of predation
Herbivory, Carnivory, and Parasitism
What factors are included in the Lotka-Volterra equations?
Prey growth rate and predator conversion efficiency
Functional Responses
Changes in the predator’s consumption rate as prey density changes.
Numerical Responses
Changes in predator population size
How does Herbivory affect plant populations?
Can lead to the evolution of various plant defenses
What are some animal defenses against predation?
Physical and Chemical Defenses, and Behavioral adaptations
What are some predator hunting techniques?
Ambush, Pursuit, and Stalking
Can predators control prey density?
Predators can influence prey populations, but it depends on various factors including predator-prey interactions
Parasitism
Organisms that live on or in a host organism, often harming it
How do hosts respond to parasites?
Hosts respond with immune or behavioral defenses.
Definitive host
The parasite reproduces in or on the host
Intermediate Host
Hosts the developmental stages of a parasite
Mutualism
A mutually beneficial interaction between two species.
Facultative mutualism
Non-obligate, mutually beneficial relationship between two species .
Coexistence
The ability of two or more species to live together in the same habitat over an extended period without exclusion
Resource Partioning
Dividing and sharing limited resources.
Character Displacement
The divergence in traits that reduces the intensity of competition.
What is a cohort in a life history table
An age or stage group
What is the Allee Effect?
When a population declines even at a low density
