Topic 10 Flashcards
What is succession?
Process by which communities or organisms colonising an area change over time
Where does primary succession occur?
With an empty inorganic surface such as bare rock or sand dune.
What are the first organism on primary succession?
Opportunists or pioneer species, such as algae or mosses.
What doe pioneer species do the start primary succession?
Can penetrate the rock surface, helping to break it into small grains, and trap organic material that willl break down to form hummus.
What starts the formation of the soil?
The inorganic rock grans and organic humus.
What occurs after there is soil in primary succession?
Species such as grass and ferns can establish a root system.
What does the grass and ferns do to the soil?
The action of their roots and the humus they form, when they die, decay and add to the soil.
What happens as the soil layer develops in primary succession?
More water and nutrients are retained and become available for plant roots, and so less hardy species can survive
How does the biodiversity increase in primary succession?
The soil becomes stronger, so more species can grow their. Larger plants can be supported.
What happens as plant diverts increases during primary succession?
The biodiversity of animals can also be supported and increase
What is a climax community?
Self sustaining community with relatively constant biodiversity. It is the most productive group of organisms that a given environment can support long term.
What is a climatic climax community?
Is the only climax community possible in a given climate. One that generally remains constant over time.
What is a plagioclimax?
Climax community that is at least in part the rule of human intervention
Example of a plagioclimax?
Chalk grassland, clearing woodland, eg
What is secondary succession?
development of an ecosystem from existing soil that is clear of vegetation.
What occurs to produce secondary succession?
As rivers shift their courses, after fires, floods, after disturbances abused by humans etc.
How similar is primary and secondary succession?
Very, but soil is already produced and formed with seeds, roots and soil organisms. The number of plants and animal present right form the beginning of succession are much higher.
What does secondary succession depend on?
Temperature, rainfall, underlying soil fertility.
What can show a whole record of stages of succession?
Sand dunes.
The area of sand closest to the sea is primary succession, with loose sands. It gradually increases in structure and plants and organisms as you increase across the beach
What is Surtsey?
A volcanic eruption burst through the seas off the coast of Iceland. The hot magma cooled rapidly and produced to form a new island. When they stopped, there was a huge 2.7 km area of volcanic rock.
What were the earliest colonisers on Surtsey?
Mounds, bacteria, fungi, followed by flowering plants.
What caused more fertility to the soil at Surtsey?
Bird droppings, fell after gulls colonised to the island.
What is microclimate?
Small area with a distinct climate that is different to the surrounding areas.
How is light an abiotic factor on populations?
Non living therefore abiotic. The amount of light in a habitat gas direct effect on number of organisms.
