Pioneer species include bacteria and lichens that can grow on bare rock and help make soil. Secondary succession occurs in a formerly inhabited area that was disturbed. Soil is already in place, so pioneer species include small plants such as grasses.
Factors affecting photosynthesis
Three factors can limit the rate of photosynthesis: light intensity, carbon dioxide concentration and temperature.
Light intensity
Without enough light, a plant cannot photosynthesise very quickly - even if there is plenty of water and carbon dioxide. Increasing the light intensity will boost the rate of photosynthesis.
A graph with rate of photosynthesis on the y axis and light intensity on the x axis. The plotted line rises steeply and then levels off to horizontal.
Carbon dioxide concentration
Even if there is plenty of light, a plant cannot photosynthesise if there is insufficient carbon dioxide.
A graph with rate of photosynthesis on the y axis and light intensity on the x axis. The plotted line rise steeply and then levels off to horizonal. During the steep part light is the limiting factor. During the horizontal part another factor has become limiting.
TemperatureIf it gets too cold, the rate of photosynthesis will decrease. Plants cannot photosynthesise if it gets too hot.
A graph with rate of photosynthesis on the y axis and carbon dioxide concentration on the x axis. The plotted line rise steeply and then levels off to horizonal. During the steep part carobn dioxide is the limiting factor. During the horizontal part another factor has become limiting.
If you plot the rate of photosynthesis against the levels of these three limiting factors, you get graphs like the ones shown above.
In practice, any one of these factors could limit the rate of photosynthesis.
Answer:
PH is a scale used to specify the acidity or basicity of an aqueous solution.
Acid soils have a pH below 7
6.5 to 7.5 for basic soils
The Old field succession is a man-made secondary succession that occurs when a farmer stops cultivating their field for a lengthy period of time.
The definition of old fields, which has been a topic of discussion among modern ecologists for some time, is that they are an intermediate stage in the natural succession of an ecosystem moving towards its climax community. Many times, old field sites are marginal lands with poor soil quality that are unfit for pasture or farming.
The terms "grass and forbs stage," "shrub and sapling stage," "pole stage," and "mature forest" are frequently used by foresters to describe these stages. Forest succession is the process by which plant communities develop in a regular, predictable manner.
When a farmer gives up on a farm, the abandoned land quickly becomes overgrown with weeds and grass.
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