UNIT 3 QCE Biology - Succession

Learning Goals explain the concept of ecological succession (refer to pioneer and climax communities and seres) differentiate between the two main modes of succession: primary and secondary identify the features of pioneer species (ability to fixate nitrogen, tolerance to extreme conditions, rapid germination of seeds, ability to photosynthesise) that make them effective colonisers

What does succession mean in an ecological context

The process by which the mix of species and habitat in an area changes over time.

What is the difference between primary and secondary succession?

In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area that was previously occupied by living things is disturbed, then re-colonized following the disturbance.

Define primary succession

The beginning step of ecological succession after an extreme disturbance, which usually occurs in an environment devoid of vegetation and other organisms.

define secondary succession

Happens when a climax community or intermediate community is impacted by a disturbance. This restarts the cycle of succession, but not back to the beginning—soil and nutrients are still present.

Sere (seral community)

An intermediate stage found in ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained.

Pioneer species

Hardy species that are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by wildfire.

Climax community

the “endpoint” of succession within the context of a particular climate and geography.

pioneer species examples

fungi, mature shrubs & trees, moss, grass,