Succession- is the term used to describe the changes in a species, over a period of time, in a particular area.
The first stage of Succession is when the Pioneer species ocupy the hostile land.Pionner species features;
-Produce vast quantities of wind dispersed seeds
-Tolerant to extreme conditions
-Photosynthesise where nutrients not avaliable
-Fix atmospheric notrogen
-Qucikly germinate seeds
Examples of Succession;
2. Lichen (pionner species) occupy soil
3.Lichen die - increasing nutrients in soil
4. Allows moss to grow
5. Moss further increases nutrients- allows fern to grow
6. Further erosion of rock and incresing of nutrient- thick layer of soil to form.
7. Change in abiotic factors- allowing more species to grow.
8. Balanced equilibruim of species formed- Climax community reached.
Climax Community- the final stage of ecological succesionin which species remain stabel until a disturbance such as a fire occurs.
Key Features of succesion;
-Abiotic factors become less hostile
-more complex food webs
- increased biomass
After a forest fire, the equilibrium between species will not longer be apparent, so the process of succession will occur again.
The changes in the abiotic environment result in a less hsotile environment and chnaging diversity.
Succesion ofan Arctic galcier;
1. Pioneer stage -lichens colonise patch of land
2. Dryas stage- roots stabalise to allow thin layer of soil to form
3. Alder stage- shrub like tree that has nitrogen fixing modules attched
4. Spruce stage- trees develop amoungst the alder.
Conservation - is the management of the Earth's natural resources by maxmising the use out of them in the future.
Humans have to maintain ecosystems and biodiversity.
Reasons for conversation;
1. Ethical- respect for living things
2. Economic - living organisms contain living organisms with a gigantic pool of genes- some of these genes could be useful in future
3. Cultural and Asethetic -habitats and organisms provide a different dimension to everyday life
Managing succession will help to conserve the earth's natural resources.
E.g Moorland- has been burnt and grazed on by sheep leading to it to never reach its climax community. It has prevented natural succession to happen to change the moorland to woodland.
How does conservation rely on Science to make decisions?
-Science understands the impacts that a lack of the earth's natural rsources will have on the environment and therfore the climax community.