What is selective pressure.

Selection pressures are external agents which affect an organism’s ability to survive in a given environment

Selection pressures can be negative (decreases the occurrence of a trait) or positive (increases the proportion of a trait)

Selection pressures may not remain constant, leading to changes in what constitutes a beneficial adaptation

Types of selection pressures include:

Resource availability – Presence of sufficient food, habitat (shelter / territory) and mates

Environmental conditions – Temperature, weather conditions or geographical access

Biological factors – Predators and pathogens (diseases)

oak trees? ? what was listed

maybe because its impossible for balloons to lift a whole entire house.