Variation in population size

Question 1

what are limiting factors of growth?

Answer 1

• mineral ions are consumed as the population becomes larger
• the population becomes so large that the bacteria at the surface prevent light reaching those at deeper levels
• other species are introduced into the pond, carried by animals or the wind and some of these species may use the bacteria as food or compete for light or minerals
• winter brings much lower temperatures and low light intensity or shorter duration

Question 2

what are the abiotic factors?

Answer 2

• temperature
• light
• pH
• water and humidity