Population ecology Flashcards
what is ecology?
the study of interactions among organisms and their environment
what is population?
all the individuals of a species that live together
what are the 3 key features of a population?
size
density
dispersion
what is size?
the number of individuals in an area
what is density?
the measurement of population per unit area
what is dispersion?
the spread of population can be clustered, random and uniform
what is biotic potential?
the natural reproductive potential of the species
what is environmental resistance?
a term used in population ecology to explain mortality rates controlled by environmental factors that prevent survival
what is a density independent environmental limiting factor ?
increase death rate whatever the population size
what is a density dependent
food supply /disease will become more prevalent limiting growth as the population increases
what has human population been like for the past 200 years?
been in a long phase of exponential growth for the past 200 years
what is the optimum population?
ideal balance between population and resources
what is overpopulation?
too many people in an area relative to the available resources
what is underpopulation?
too few people to use resources efficiently for a given level of technology
what is the biosphere?
the biological components of the Earth’s systems
what is the carrying capacity?
the maximum population size that an area can sustain indefininetly
what is the ecological footprint?
a measure of the demand placed by humans on Earth’s natural ecosystems
what is an overshoot?
refers to a point when the population and its associated consumption resources exceeds the long term carrying capacity
what is the total productivity bio-capacity?
all the food water and energu resources produced by the earths natural systems in order to sustain us
carrying capacity-professor william rees
- flexible depending on average lifestyle
- varying levels of consumption of resources
- earth may support 10 bil at modest level of consumption but we will have a lower carrying capacity if we waste resources and live the life of HICS
Rees calculation of carrying capacity
measure the total productivity bio capacity of earth by dividing it by total population
implications of carrying capacity
-concept of carrying capacity introduces a limit to population growth
implications of a growing ecological footprint
climate change more land used for settlement and industry degradation of natural ecosystems increased threat of species extinction depletion of fish stocks overgrazing
what is the case study used for population growth?
Easter island
where did it all go wrong … Easter island
easter island is a reminder that there are finite limits on our environment
as a global society…
if we continue to use the environment in an unsustainable way then we will have to learn to live differently and live with less
