Ecological factors and light
Answers are for parents and teachers.
1
Three plants of one species got equal fertiliser but were watered dry, wet and moderately. Which grows best and why?
The moderately watered one – moisture is in its optimum; in the others moisture becomes limiting.
2
Sort into abiotic, biotic or anthropogenic: rainfall, canal digging, a predator, slope exposure, fungal mycorrhiza.
Rainfall, slope – abiotic; canal digging – anthropogenic; predator, mycorrhiza – biotic.
3
Describe two practical uses of photoperiodism in agriculture.
Controlling flowering in greenhouses by artificial lighting; choosing sowing dates suited to the region.
4
Both swallows and bats catch flying insects and live in the same area. Why is there no strong competition between them?
The swallow hunts by day and the bat at dusk and at night: their active times differ, so their niches are separated.
5
Simplified «long-day / short-day» lists in the textbook are not always exact: tomato and cucumber are often day-neutral. Why must variety and conditions be taken into account?
Cultivated varieties have been bred to change day-length needs; the response also depends on temperature and other factors.