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

You have to do counselling of a diabetic patient and the family members when you are working in a diabetic clinic or community setting in health center. To be an effective counsell

Explain the chemical properties of milk Autoclaving milk, wherein temperature of around 121 o C is achieved, causes browning. The brown colour is due to the heat effecting an i

Plasma Proteins - Circulation The total protein concentration of the plasma is around 7% only. The plasma proteins are of three types - serum albumin (4%), serum globulin (2.7

Counselling Diabetic Travellers The counsellor needs to educate a diabetic patient and /or his family members to following issues when such patients plan to travel: ·  Plan

Explain the Membrane Equilibria? A semipermeable membrane used to separate two liquid phases can, in principle, be permeable to certain species and impermeable to others. A mem

A Molecule of DNA is 2.17 um long. The ends of the molecule become strongly ionixed: negative on one end, positive on the other. The helical molecule acts like a spring and compres

In humans, starch digestion begins in the buccal cavity but stops in the Stomach. Why? Name the two most biodiversity-rich zones of India. Name the hormone that makes the p

Q. How do chordates reproduce? Reproduction in beings of the phylum Chordata is sexual, with the exception of urochordates that can be also reproduce asexually. In some classes

Question 1: (a) Give, in order, the major categories of taxonomic classification. (b) Differentiate between the five kingdoms of organisms. (c) Differentiate between net