Sigmoid growth curve, Biology

GROWTH CURVES -

S-shaped or sigmoid -

Described by Verhuhst in 1839.

It shows 5 phases -

(i) Lag phase

(ii) Positive acceleration phase

(iii) Exponential phase

(iv) Negetive accesleration phase

(v) Stationary

1480_sigmoid growth curve.png

1.       Lag phase -

  • Early stage of curve.
  • When new individuals come in new environment so minimum growth occur in these phase.
  • It is due to absence of new resources.
  • It is due to lack of adaptations.

2.       Positive acceleration phase -

  • Growth rate is increased.
  • Birth rate increases.
  • Death rate is minimum.

3.       Exponential phase -

  • Individuals become adaptated.
  • Rapid growth occur.
  • Birth rate very high.
  • Death rate very low.

4.       Negetive accesleration phase -

  • Growth rate decreases.
  • Available sources become limited.

5.       Stationary -

  • Resources are limited.
  • Birth rate is equal to death rate.
  • So growth rate is zero.
  • In the growth curve of bacteria after stationary phase growth decreases due to unavailability of resources.

2258_sigmoid growth curve1.png

If semi log curve is drawn for bacteria curve is in the form of straight line.

897_sigmoid growth curve2.png

Posted Date: 10/4/2012 7:20:35 AM | Location : United States







Related Discussions:- Sigmoid growth curve, Assignment Help, Ask Question on Sigmoid growth curve, Get Answer, Expert's Help, Sigmoid growth curve Discussions

Write discussion on Sigmoid growth curve
Your posts are moderated
Related Questions
Micrographia is abnormally small, cramped handwriting and/or the progression to continually smaller handwriting. This is one of the symptoms of Parkinson''s disease.

AQUATIC ADAPTATION IN ANIMALS

Explain Trifluridine  (Viroptic)  Trifluridine is a nucleoside analog active against herpes viruses, including acyclovir-resistant strains. Marketed in an ophthalmic preparatio

Habits of patients- Implants Smoking has been shown to predispose to poor bone quality by reduced vascularity. Therefore it is prudent not to accept heavy smokers as implant pa

Effect of processing on mineral content of foods Minerals are comparatively stable under processing conditions such as heat, light, use of oxidizing agents and extremes in pH.

Organism:-Fungi  Advantages:- Easy to harvest from culture medium. Texture of the fungi improves the functional properties of proteins. Disdvantages:-

Provide a link to the graph, describe the variables, and interpret the meaning of the graph

A plant grown from one of Mendel's yellow peas is selfed. Five progeny peas are obtained from this self and they are all yellow. If the original selfed plant had been homozygous, w

Bronchial asthma: Bronchial asthma is characterised by bouts of  dyspnoea as a result of  temporary narrowing of bronchi due to bronchial spasm, mucosal edema and thick secret

Criteria for Diagnosis of Respiratory Failure PaO 2 , PaCO 2 , > 50 mm Hg.  Vital Capacity Respiration > 30/min or below 8/min.