Bio Ch 44 Flashcards
Ecology
study of the interactions among all organisms and with their physical environment
Habitat
the place where the organism lives
Population
all the organisms belonging to the same species within an area at the same time
Community
all the populations of multiple species interacting at a locale
Ecosystem
composed of the community of populations along with the abiotic environment
Biosphere
encompasses the zones of the Earth’s soil, water, and air where living organisms are found
Demography
statistical study of a population, such as its density, its distribution, and its rate of growth, which is dependent on such factors as its mortality pattern and age distribution
Population density
number of individuals per unit area
Population distribution
pattern of dispersal of individuals across an area of interest
Resources
nonliving (abiotic) and living (biotic) components of an environment that support living organisms
Limiting factors
environmental aspects that determine where an organism lives
Rate of Natural Increase
growth rate; dependent on the number of individuals born each year and the number of individuals that die each year
Biotic potential
highest possible rate of natural increase for a population
Cohort
all the members of a population born at the same time
Survivorship
probability of newborn individuals of a cohort surviving to particular ages
Age Structure Diagrams
in demographics, a display of the age groups of a populations; a growing population has a pyramid-shaped diagram
Semelparity
members of the population have only a single reproductive event in their lifetime
Iteroparity
members of the population experience many reproductive events throughout their lifetime
Exponential growth
number of individuals added each generation increases as the total number of females increases
Logistic growth
population increase that results in an S-shaped curve; growth is slow at first, steepens, and then levels off due to environmental resistance
Carrying Capacity (K)
maximum number of individuals of a given species the community can support
Density-independent factor
intensity of the effect does not increase with increased population density
Density-dependent factors
biotic factors considered this; percentage of the population affected does increase as the density of the population increases; competition, predation, disease, and parasitism are all biotic factors that increase in intensity as density increases
Competition
can occur when members of a species attempt to use the same resources (light, food, space) that are limited in supply
Predation
occurs when one living organism, the predator, eats another, they prey
r-Selection
Favorable life history strategy under certain environmental conditions; characterized by a high reproductive rate with little or no attention given to offspring survival
k-Selection
favorable life-history strategy under stable environmental conditions characterized by the production of a few offspring with much attention given to offspring survival
Doubling time
the length of time it takes for the population size to double
More-Developed Countries (MDC’s)
North America, Europe, Japan, & Australia; population growth is low, and the people enjoy a high standard of living
Less-Developed Countries (LDC’s)
certain countries in Latin America, Africa, & Asia; population growth is expanding rapidly, and the majority of people live in poverty
Demographic transition
sequence of events (decreased death rate followed by decreased birth rate)
Zero population growth
no increase in population size
Replacement reproduction
if there are more young women entering the reproductive years than there are older women leaving them, _____ _____ will still result in population growth
