Level of life
Organism
An individual living thing, from a single bacterium to a tree or a person.
Population
All the members of one species living in the same area at the same time.Source: OpenStax, 2018
Level of life
How Population connects
Population is made of
Population makes up
Level of life
Community
All the populations of different species living and interacting in one area.
Population is described by
Idea or model
Population dynamics
How population sizes change through births, deaths and interactions such as predation. Mathematical predator-prey models date to the 1920s.
Idea or model
Hardy-Weinberg equilibrium
Without selection, mutation, migration or drift, allele and genotype frequencies stay the same from generation to generation.
Population is related to
Process
Evolution
The process by which living things change over generations through changes in their genomes.
Your progress
Sources & further reading
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Biology 2e (opens the original in a new tab)
OpenStax (2018). OpenStax, Rice University.
Free introductory college textbook.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)