Marret Smekens Ir. The Department of Plant Population Biology studies the relationships between living plants and their environment. In a population biological approach to ecology, attention is given to variation at the individual level and its demographic and evolutionary consequences at the population level. The fate of any population depends on the performance of its individuals. If variation in a phenotypic trait is correlated with fitness and if the variation has a genetic basis, natural selection generates adaptations to the ambient environmental conditions.
Genetic drift can also cause population changes, especially in small populations.
However, such changes are in a random direction and often disadvantageous. The transmission of genes from one generation to the next depends on the genetic or breeding system. The genetic system affects the reshuffling of genes in each generation, and hence the expression of favorable and deleterious genes. Many theories have been put forward to explain the occurrence and diversity of these genetic systems, but empirical data on its relation with ecological factors is as yet scarce. The plant genome is divided over different compartments, with different ways of transmission.