Competition and population sizeIB MYP Biology: Mind map

Exam questions on Competition and population size

1. A forestry team in Poland planted young oak seedlings in two plots of the same woodland clearing. In plot 1 the seedlings were planted 10 cm apart. In plot 2 they were planted 1 m apart. Both plots have the same soil and receive the same rainfall.
   Explain why the seedlings in plot 1 are likely to grow more slowly than those in plot 2.2 marks
2. On a beach in Namibia, a colony of Cape fur seals gathers every year to breed. Each adult male defends a small patch of beach and tries to keep other males away from the females on it. The colony grows larger each year, but the amount of fish in the nearby sea stays about the same.
   Explain why competition for food between the seals is likely to increase as the colony grows.2 marks
3. A student grew yeast in a sealed flask containing a fixed volume of sugar solution kept at 30 °C. Every three hours she counted the yeast cells in a small sample. The count was 2000 cells per mm³ at 0 hours and 2400 at 3 hours. It rose to 38 000 at 9 hours and 52 000 at 15 hours, stayed at about 52 000 until 30 hours, and then fell to 20 000 by 48 hours.
   Name the phase of population growth shown between 0 and 3 hours, between 3 and 9 hours, and between 15 and 30 hours.3 marks