Energy & Ecosystems
- Created by: beth-marie2511
- Created on: 20-06-16 23:00
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- Energy & Ecosystems
- Primary Succession
- The starting point is bare ground (e.g. rock)
- The introduction of plants/animals into areas that have not previously supported a community
- First organism to colonise an area = Pioneer Species
- They form a pioneer community
- Features of Pioneer Species
- Early arrivals
- Can tolerate extreme conditions (e.g. low nutrient levels)
- Very good means of dispersal (usually by wind)
- Unable to compete for resources
- Not influenced by or dependent upon animal species
- May be able to fix nitrogen and build up soil nutrients
- Secondary Succession
- A community is damaged and the soil is left for plants to colonise
- The re-introduction of organisms into a bare habitat previously occupied by plants and animals
- If the original vegetation is removed the area is quickly re-colonised by different plants and animals
- SERES = The different stages in a succession when particular communities dominate
- How Does Succession Happen?
- EXAMPLE: In Iceland the island of Surtsey was created by a volcanic eruption
- Algae and lichen colonised the bare rock
- Enough soil was produced for larger plants to grow from the build up of dead and decaying organisms
- These plants succeeded the algae and lichen
- Larger plants succeeded the smaller plants until a stable community was reached
- This is a CLIMAX COMMUNITY
- Sand dunes are interesting because they display all the stages of succession in the same place at the same time
- Features of Climax Community Species
- Species found in the end point community
- Large seeds with a large energy store so seedlings can survive low light intensity
- Specialised niche
- Unable to tolerate great fluctuations in the water content of soil
- Strongly influenced by other organisms
- Competitors
- Herbivores
- Seed dispersal agents
- Soil micro-organisms
- Primary Succession
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