Ecological pyramid of the organisms in a lake in terms of energy in kJ m-2 y-1
LEVEL 4 _| fish-eating birds = ?
LEVEL 3 __| fish = 460 kJ m-2 y-1
LEVEL 2 ___| insects = 4614 kJ m-2 y-1
LEVEL 1 ____| plants = 31 873 kJ m-2 y-1
1) What is the energy efficiency transfer between the first two trophic levels?
2) If the energy efficiency transfer through the food chain from plants to fish-eating birds is 0.062 %, what energy is contained in the 4 level?
3) Newe fish were introduced into lake and were found to increase exponentially with a rate of increase (i) per year per fish of i = 5 y−1. Calculate how many fish there will be in 6 years from an initial introduced population of 10 fish.
Nt = N0 * it
- there are equal numbers of male and female offspring
- each pair of fish breeds once each year and produces ten offspring, so the rate of increase per year per fish, i = 5 y−1
- after breeding that the fish don’t live to the next year