Chapter 7 Flashcards
population growth rate
change in population size over time (births - deaths over specific time period)
population
all individuals of species that live in same geographic area and are able to interact and interbreed
population dynamics
changes over time of population size and composition
minimum viable population
smallest # of individuals that would still allow population to persist and grow, ensuring long term survival.
Evaluation of positive & negative impacts of proposed environmental action, including alternative actions
Environmental impact statement
of individuals per unit area
Population density
Location & spacing of individuals within their range
Population distribution
Individuals found in groups or patches within habitat
Clumped distribution
Individuals spread out irregularly with no pattern
Random distribution
Individuals spaced evenly, due to territorial behavior or mechanisms for suppressing growth of nearby individuals
Uniform distribution
Elk stay in herds. Example of
Clumped distribution
Seeds that germinate where they fall - example of
Random distribution
Creosote bush produces toxins that prevent other bushes from growing close by, example of
Uniform distribution
of births / 1000 / year
Birth rate
of deaths / 1000 / year
Death rate
Maximum rate population can grow due to births if everyone survives & reproduces
Biotic potential (r)
Population progressively larger each breeding cycle; J curve when plotted over time
Exponential growth
Population size increases rapidly at first, slows as population becomes larger, S curve when plotted over time
Logistic growth
Population size a particular environment can support indefinitely w/o long term damage
Carrying capacity (k)
Factors whose impact on population increases as population goes up. (Disease)
Density dependent
Factors whose impact on population not related to population size (storm, avalanche)
Density independent
How quickly population can potentially increase, reflecting biology o the species (life span, fecundity, maturity rate)
Reproductive strategies
Species - high biotic potential, & share characteristics such as short lifespan, early maturity, high fecundity
R-selected species
Capacity to produce young in great numbers
Fecundity
Species - low biotic potential, share characteristics such as long lifespan, late maturity, low fecundity, logistic population growth
K-selected species
Larger herds result in more competition for food.
Example of density _____ factor that affects population size
Density dependent
Infectious diseases spread more easily in large populations of animals. Example of density _____
Density dependent
Predators - easier to capture prey from larger populations.
Example of density _____
Density dependent
Fires / floods affect population
Density _____
Density independent
Storms affect populations
Density _____
Density independent
Avalanche or other natural disasters affect population size
Density _____
Density independent
Fluctuations - population size that produce very large population followed by crash that lowers the population size drastically, followed again by increase & then crash
Boom & bust cycle
Local extinction of a species
Extirpation
