In E. coli, rRNA synthesis from the seven rRNA operons responds to cellular growth rate and to changes in the availability of crucial nutrients, particularly amino acids. The regulation coordinated with amino acid concentrations is known as the stringent response.

TLS Online TPP Program

#Id: 5348

#Unit 10. Ecological Principles

Many populations breed seasonally, often once a year some are quarterly or monthly.

These are iteroparity or semelparity.

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#Id: 5349

#Unit 10. Ecological Principles

R0<1, The population eventually declines to extinction 

R0=1, The population size remains constant

R0>1, The population increases

TLS Online TPP Program

#Id: 5350

#Unit 10. Ecological Principles

TLS Online TPP Program

#Id: 5351

#Unit 10. Ecological Principles

λ represents the finite rate of population change over some time interval, often a year

λ = N1/N0

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#Id: 5353

#Unit 10. Ecological Principles

Populations grow when R0 or λ>1, populations decline when R0 or λ<1, and are at equilibrium when R0 or λ=1

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#Id: 5368

#Unit 10. Ecological Principles

The simplest method to measure population density is to visually count the number of organisms in a population in a given habitat.