These are organisms that are able to colonise a disturbed habitat such as an area of bare soil or rock. They have adaptations that enable them to survive and reproduce in the harsh environment. Primary colonisers typically have effective methods of dispersal. |
A sere is a stage in a succession. The community of organisms in each sere are usually quite distinctive. |
Successions are characterised by a series of communities that inhabit the area as its physical features change. However, the succession eventually reaches a stable community called the climatic climax. The structure of this community depends the soil and climate. In the UK, most successions lead to woodland. |
The features of an organism that enables it to survive to reproduction in its habitat. |
Some organisms are able to environments where there is no stable soil. They have to be able to extract nutrients from the air and to attach themselves to the surface. As they grow and produce dead matter, they start to develop soil and weather the surface. Other colonisers then start to grow in the area and the pioneers are rapidly out competed. Lichens are an example of pioneers of bare rock. |
The diversity of living things in a habitat increases as the succession takes place. The developing soil enables a wider range of plants to colonise and they provide food and shelter for animals. The animals in turn provide food for secondary consumers. |
Competition is the primary factor that causes the change in communities in the succession. Each community of plants and animals alters the environment making it less suitable for them and more suitable for other colonisers. |
A series of communities that develop in an area over time. If the succession develops from an area with no community, it is called a primary succession e.g. on exposed rock. If the succession develops from an area that has been prevented from changing e.g. by agriculture, it is called a secondary succession. |
The number or population of living things in a fixed area. |
The percentage of an area covered by a plant. The higher the cover, the better the plant can compete for light and the more dominant the plant will be in the community being studied. |
The proportion of samples that an organism is present in. An organism with a frequency of 0.5 or 50% was found in half of the samples taken. |
A green plant that supports itself with its cell's turgor. Herbaceous plants are often dominant in the second stage in a succession. Later stages become dominated by woody plants. The first stage is often dominated by other photosynthetic organisms such as algae and lichens. |
The collection of living things living in a habitat. |