Ecological Succession - University of North Texas

嚜激cological Succession

? Succession- changes which increase the

community complexity over time

? Primary succession- succession which takes

place when bare, lifeless substrate becomes

available for colonization (VERY slow)

每 retreating glaciers

每 emerging islands

每 formation of new lake

Ecological Succession

1

Ecological Succession

? Secondary Succession- re-colonization

following disturbance (much faster than

primary succession)

每 fire, floods, bulldozers, etc

Secondary Succession

2

Ecological Succession

? What makes succession happen?

每 Tolerance

?only species which can tolerate full range of

conditions survive

?early succession- r-selected species dominate

because they have broader ※tolerance ranges§

每 Facilitation-

species present change the environment and

make it more hospitable for others

每 Inhibition- species present change the environment and

make it less suitable for themselves

Keystone Species

? In many communities

one or a few species

appear to be very

important in

maintaining the

community

structure＃ these are

called ※Keystone§

species.

3

Material Cycling

? Energy flows / matter cycles

每 note: true at STP...

? Since there is a finite amount of each element on

earth today, essential elements (and compounds)

must be recycled over and over.

? Examples每 water

每 carbon

每 nutrients (nitrogen, phosphorus, iron, etc)

4

Material Cycling

? Carbon Cycle

CO2

Photosynthesis

(stores sun＊s energy)

Respiration

(releases energy)

Organic

Carbon

Photosynthesis by plants

5

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