The degree of supercoiling of bacterial DNA is maintained by regulation of the net activity of topoisomerases, I and II.

TLS Online TPP Program

#Id: 2183

#Unit 10. Ecological Principles

Succession, the gradual and continuous change in species composition and community structure over time

TLS Online TPP Program

#Id: 2184

#Unit 10. Ecological Principles

Causes Succession

TLS Online TPP Program

#Id: 2185

#Unit 10. Ecological Principles

Allogenic factors –  Chemical weathering of rocks or filling in by sand/silt in a pond

Autogenic factors– Autogenic factors include – Immigration, Growth, Reaction, Coactions

TLS Online TPP Program

#Id: 2186

#Unit 10. Ecological Principles

TLS Online TPP Program

#Id: 2187

#Unit 10. Ecological Principles

Step in succession

1. Nudation 

2. Migration 

3. Ecesis 

4. Aggregation

5. Competition 

6. Reaction 

7. Stabilization

TLS Online TPP Program

#Id: 2188

#Unit 10. Ecological Principles

Primary succession - refers to succession on a newly exposed site that was not previously occupied by soil and vegetation.

Secondary succession - refers to succession on a site that has already supported life but that has undergone a disturbance.