Structure of populations and biocenoses
Answers are for parents and teachers.
1
How many individuals live in 150 km² at a density of 4 per km²?
600
2
A population has 500 individuals; 60 were born and 35 died during the year. What is the number at the end?
525
3
Why is a very small population at risk of extinction? Give two reasons.
Finding mates becomes hard; inbreeding reduces genetic diversity; chance events have strong effects.
4
Order forest tiers by height: herbs, shrubs, tall trees, lower trees, mosses.
Tall trees → lower trees → shrubs → herbs → mosses.
5
How does living in a large herd benefit saiga antelopes?
Faster detection of danger and joint defence; the chance that any single animal is attacked decreases.