Succession Flashcards
Succession
Change in structure and composition of species in a community over time
Primary succession
Succession in a habitat that has never before been colonised
Example , bare rock
Name a natural disaster that could lead to primary succession
A volcanic eruption
Secondary succession
The reintroduction of organisms into a bare habitat previously occupied by plants and animals
Events that could lead to secondary succession
Tree felling
Bush fires
Deforestation
Pioneer species and examples
The first organisms to grow in a new habitat. They are often adapted to very harsh environments
Examples are lichens
Describe the stages of primary succession
Lichens grow on the bare rock or the area that has never been colonised
The lichens decompose , forming a very thin layer of soil on the rock over time
Mosses are able to root into the first soil formed by the decomposing lichen. They are still able to survive under harsh conditions
The decomposing moss and lichen establish soil sufficient for the roots of low growing herbaceous plants and grasses. Seeds are blown by wind into the habitat to establish a grassland community
Grasses are outcompeted by the more woody plants , who block sunlight from reaching the grasses. This prevents the growth of grasses underneath them
A climax community is then established eventually
Seral Stages
the different stages in a succession when particular communities dominate between pioneers and the climax
climax community
the final stable collection of plants and animals that succession produces. These plants and animals are the best adapted to the conditions of their habitat
which between the two types of succession is much quicker, and why
The root systems are undisturbed, so stumps and other plant parts from previously existing plants can rapidly regenerate
the fertility and structure of the soil has already been substantially modified by previous organisms to make it more suitable for growth and colonisation
disruption climax
a way to preserve specialised plant and animal life( organisms that might otherwise go extinct) through factors such as poor soil, and human behaviour
state five events that could lead to a disruption climax
fire
grazing
mowing
ploughing
mineral extraction and building
Give an example of a disruption climax
The grazing of sheep have maintained the open habitats of much of upland Britain. This prevents the land from being returned into a woodland through succession. this makes it a more suitable habitat for certain plant species, as they might be more adapted to conditions like the availability to high levels of sunlight.
