Essential idea: Dynamic biological processes impact population density and population growth.
Fish populations, such as the schooling Anchovies (left) being hunted by the Bluefin Trevally (right) are an excellent example of how dynamic populations are. The process affecting population density here is mortality caused by predation.
Understandings, Applications and Skills
|C.5.U1||Sampling techniques are used to estimate population size.|
|C.5.U2||The exponential growth pattern occurs in an ideal, unlimited environment.|
|C.5.U3||Population growth slows as a population reaches the carrying capacity of the environment.|
|C.5.U4||The phases shown in the sigmoid curve can be explained by relative rates of natality, mortality, immigration and emigration.|
|C.5.U5||Limiting factors can be top down or bottom up.|
|C.5.A1||Evaluating the methods used to estimate the size of commercial stock of marine resources.|
|C.5.A2||Use of the capture-mark-release-recapture method to estimate the population size of an animal species.|
|C.5.A3||Discussion of the effect of natality, mortality, immigration and emigration on population size.|
|C.5.A4||Analysis of the effect of population size, age and reproductive status on sustainable fishing practices.|
|C.5.A5||Bottom-up control of algal blooms by shortage of nutrients and top-down control by herbivory.|
|C.5.S1||Modelling the growth curve using a simple organism such as yeast or species of Lemna.|
[Text in square brackets indicates guidance notes]
Presentation and notes
The presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
Population growth curves
Population size, Population growth and Factors limiting population growth by Click4Biology
Exponential population growth by The Biology Project
Managing fish populations
End overfishing by Blackfish
_Dan Barber: How I fell in love with a fish by TED
Sustainable fisheries by MarineBio
Scientific advice on managing fish stocks by European Commission
Nature of Science
Avoiding bias—a random number generator helps to ensure population sampling is free from bias. (5.4) [covered in C.5.A2 and C.5.S1]
The issues around the growing global human population are of international concern regardless of different growth rates in different countries.
Hans Rosling talks about global population by using boxes