Examples of natural selection, Biology

Assignment Help:

EXAMPLES OF NATURAL SELECTION -

1.       INDUSTRIAL MELANISM -

  • First studied by Fischer & Ford (1845) on pepperd moth (Biston betularia) of two types : grey moth (B. betularia betularia) and black moth (B. betularia carbonaria); the black moth population in Britain in (1845) was 1% which by 1895 came to 99%, it was thought that due to industrial pollution the grey moth changed into black. When coal run industries were replaced by electric / petroleum run industries the number of grey moths again increased (also correlated as reverse evolution) as pollution did not eliminate the gene of grey color.
  • As explained by Neo-Darwinians both populations (grey & black) existed together, the environment favoured the one and disfavoured the other at different times resulting into their changed frequency.
  • Bernard Kettlewell (1950) tested this by releasing equal numbers of grey and black moths in both polluted (Birmingham) and unpolluted (Dorset) areas. Later he captured 19% grey and 40% black moths from polluted areas and 12.5% grey and 6% black from unpolluted areas. This indicates the patterns of differential survival of the moths in respectively areas.

2.       SICKLE CELL ANAEMIA -

  • It is a genetic disorder caused by a single base substitution in a gene.
  • The mutated gene changes the normal haemoglobin (HbA) to defective haemoglobin (HbS) and also makes the red blood corpuscles sickle shaped.
  • The persons homozygous for the defective haemoglobin (HbS, HbS) die at an early age. In the heterozygous (HbA, HbS) the cell containing abnormal haemoglobin become sickle-shaped, and unable to bind oxygen efficiently.

3.       BIO-INDICATOR PLANTS & ANIMALS -

  • Plants which are specialized to grow under specific habitual conditions so that their presence in an area can indicate the same.
  • Prosopis eineraria. P. dilensis, Acacai glandulosa. -Underground water
  • Impatiens balsamina - Zinc (Zwar zinc mines, Udaipur)
  • Haplopappus and Astragulus species - Selenium tolerant plant from U.S.A.
  • Agrostis tenuis - On tailing of lead mines in wales, U.K. the variety from normal pasture couldn't survive on Pb-rich soil.
  • Tubifix (Animal) - Pollution in water.

Related Discussions:- Examples of natural selection

Why influenza activity is mandatory in the united states, Healthcare provid...

Healthcare provider reporting of influenza activity is mandatory in the United States.

Respiration, abnormal lung volumes and capacities

abnormal lung volumes and capacities

Define how to prevent the cancer, Define How to Prevent the Cancer? A c...

Define How to Prevent the Cancer? A continuing and urgent need is there to take all steps to prevent cancer. Cancer rates are set to increase another 50 percent by the year 202

BiologicaL METHODS.., GIVE THE SHORT DETAIL OF HE BIOLOGICAL METHODS

GIVE THE SHORT DETAIL OF HE BIOLOGICAL METHODS

Father, who is the father of science

who is the father of science

Nucleic acids, Nucleic Acids Friedrich Miescher  (1868) discovered the ...

Nucleic Acids Friedrich Miescher  (1868) discovered the presence  of these compound  in protoplasm ,but Altman (1889) introduced the term Nucleic acid. These  acids are the lar

What are deciduous trees, What are deciduous trees? Deciduous trees are...

What are deciduous trees? Deciduous trees are plants that lose their leaves in a period of the year. In the case of the deciduous trees of the temperate forest the fall of the

Phenotypic classes, 1. A pure-breeding black, smooth guinea pig was mated t...

1. A pure-breeding black, smooth guinea pig was mated to a pure-breeding white, rough female. They produced several litters, and eventually, five males and twenty females resulted

Define fat requirement for cancer patients, Define Fat requirement for canc...

Define Fat requirement for cancer patients? During cancer there is enhanced mobilization of free fatty acids from adipose tissues resulting in subsequent depletion of total bod

First systematic theory in psychiatric nursing, First Systematic Theory in ...

First Systematic Theory in Psychiatric Nursing: Hildegard Peplau, one of the nurse-theorist, published a book on Interpersonal Relations  in Nursing (1952) and gave-the introd

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