Both siRNAs and miRNAs are generated from longer RNA molecules by the enzyme Dicer, an RNase III–like enzyme that recognizes and digests longer dsRNAs or the stem-loop structures formed by miRNA precursors.  The siRNA and miRNA products are typically 21–23 nucleotides long

TLS Online TPP Program

#Id: 5947

#Unit 10. Ecological Principles

TLS Online TPP Program

#Id: 5948

#Unit 10. Ecological Principles

Efficiency of Energy transfer The efficiency of energy transfer is influenced by the established laws of thermodynamics.

Efficiency of consumers as energy transformers is trophic-level transfer efficiency

TLS Online TPP Program

#Id: 5949

#Unit 10. Ecological Principles

Trophic-level transfer efficiency

 

TLS Online TPP Program

#Id: 5950

#Unit 10. Ecological Principles

Trophic-level transfer efficiency is low for the two reasons

a- Many organisms cannot digest all their prey.  

b- Much of the energy assimilated by animals is used in maintenance.

c- The dead organisms and feces become dinner for decomposers.

TLS Online TPP Program

#Id: 5951

#Unit 10. Ecological Principles

Consumption efficiency 

Consumption efficiency is the proportion of production at one trophic level (Prod n -1) that is eaten by, or ingested, by the next trophic level (In)

TLS Online TPP Program

#Id: 5952

#Unit 10. Ecological Principles

Consumption efficiencies  Forests range from 1–2%.  In grasslands, most plants are non woody range from 30–60%.  In aquatic ecosystems (most plant and algal biomass can be consumed by herbivores) range from  60–99%.