Sigmoid growth curve, Biology

Assignment Help:

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


Related Discussions:- Sigmoid growth curve

Organism to present a large intestinal surface, Q. After digestion the next...

Q. After digestion the next step is absorption done by cells of the mucous membrane of the intestine. For this task a large absorption surface is an advantage. How is it possible i

Causes of malnutrition in inflammatory bowel disease, Q. Causes of Malnutri...

Q. Causes of Malnutrition in Inflammatory Bowel Disease? The causes of malnutrition include: • Decreased oral intake, which can be disease induced due to abdominal pain, dia

Explain the carbohydrates and fat requirements during sepsis, Explain the C...

Explain the Carbohydrates and Fat Requirements during Sepsis? Carbohydrates should constitute nearly 60% to 70% of the total energy. Glucose is the primary calorie substrate in

What units are the nucleic acids constituted, Q. Of what units are the nucl...

Q. Of what units are the nucleic acids constituted? What are chemical entities that compose that unit? The Nucleic acids are formed by sequences of nucleotides. Nucleotides

Accessory food substances or vitamins, Q. Accessory Food Substances or Vita...

Q. Accessory Food Substances or Vitamins ? Bacteria also vary in their need for vitamins or accessory growth factors. Some microorganisms are unable to synthesize some or all o

Carbohydrates requirement during diabetes, Q. Carbohydrates requirement dur...

Q. Carbohydrates requirement during diabetes? Carbohydrates: These to a large extent depend on the food habits. Complex carbohydrates with more fibre are recommended to simple

Explain ringworm in humans, Ringworm in humans is caused by : 1. Bacteri...

Ringworm in humans is caused by : 1. Bacteria 2. Fungi 3. Nematodes 4. Viruses Fungi

Explain secretion of parathormone and calcium blood level, What is the rela...

What is the relation between secretion of parathormone and the calcium blood level? The parathormone enhances the calcium blood level as it stimulates the resorption (remodelat

Male reproductive disorders-cryptorchidism, Cryptorchidism Cryptorchid...

Cryptorchidism Cryptorchidism or incomplete descent of testis or retention of testis in the abdominal cavity occurs in all domestic species but is seen most commonly in stalli

Symptoms of aortic regurgitation, Q. Symptoms of aortic regurgitation? ...

Q. Symptoms of aortic regurgitation? Patients with chronic severe AR may be asymptomatic for many years and it may be picked up on routine examination. Some patients may remain

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd