Population Ecology Flashcards
Population Ecology
Studying the structure and dynamics of populations and their interactions with the environment
Genet
Genetic individual arising from a zygote
Ramets
Modules produced asexually by the genet
Clones
Characteristics of Populations
Population Structure
Spatial
Temporal
Population Structure
Proportions of individuals of various ages, stages, sizes and sexes
Spatial
Distribution and range
Abundance and density
Spatial dispersion pattern (spacing of individuals)
Temporal
Populations changes (movement of individuals via immigration and emigration(
Demography
Statistical study of the size and structure of populations and changes within them
Age/Stage/Size Structure part of Demography
Age, stage. size of individuals will influence reproductive rates, death rates, vigor, survival
What is Age/Stage/Size Structure characterized by?
Specific age categories
Life history stages (pre-reproductive, reproductive, post-reproductive)
How is age structure of a population determined?
Determining the age distribution of its members
What techniques are used to age animals?
Tooth wear, skull characteristics, plumage changes.
Primary Sex Ratio
Sex ratio at conception, tend towards 1:1
Secondary Sex Ratio
Ratio at birth
Tends to be weighted towards mals, but can shift towards females in adult age classes, due to physiological and behavioural differences
What are Sex Ratio Shifts caused by?
Condition of mother, time of season, temperature, differential survival
Distribution of Population
Spatial location based on the presence or absence of individuals, can be measured at multiple scales
How is the distribution of a population determined?
Presence or absence of suitable habitat
Geographic Range
Area that encompasses all individuals of a species
Limits of Geographic Range
Geographic barriers to colonization
Interactions between organisms
Range Expansion
Result for populations that have been introduced to a region where they did not previously exist
Abundance
Size of a population, the total number of individuals in a population in a given area
Factors affecting Abundance
Area and population density
Population Density
Individuals per unit area
Ways of measuring abundance
Crude Density
Ecological Density
Crude Density
Number of individuals per unit area/volume
Ecological Density
Number of individuals per unit are or per unit volume that is habitable
Dispersion
Position of individuals relative to each other
Patterns of Dispersion
Random
Uniform
Clumped
Random
An individuals’s position is independent of others
Uniform
Often results from negative interaction among individuals
Clumped
Most Common
Results from patchy environmental conditions and resources, social grouping and interactions, ramet dynamics
