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

What an enzyme is called, The substance that is worked on by an enzyme is c...

The substance that is worked on by an enzyme is called: a. product b. coenzyme c. substrate d. inhibitor

Definition of somatoform disorders, Definition of Somatoform Disorders: ...

Definition of Somatoform Disorders: The term 'Somatoform Disorders' was introduced in the scientific literature by the American Psychiatric Association in the  third edition o

Do primary amines can act as bases, Primary amines can act as bases; they c...

Primary amines can act as bases; they can- Select one: a. Absorb a proton to become R-NH2+2 b. Release a proton to become R-NH2+ c. Absorb a proton to become R-NH3+

Myoglobin, Myoglobin We can build up the structure of haemoglobin by c...

Myoglobin We can build up the structure of haemoglobin by considering a single unit or monomeric form caned myoglobin. This consists of a single polypeptide chain the globin i

Goal of dietary management for gdm, Q. Goal of dietary management for GDM? ...

Q. Goal of dietary management for GDM? The goal of dietary management for GDM is to provide the pregnant woman with adequate energy, commonly known as "calories", and to ensure

What is the important characteristics of soy protein, The important functio...

The important functional characteristics of soy protein The most important functional characteristics of soy protein concentrates are water-binding (water adsorption) capacity,

Explain the periodic table of the elements, Explain the periodic table of t...

Explain the periodic table of the elements ? Periodic Table of the Elements :  An element is a pure substance composed of atoms all of a single kind. It cannot be broken down

Define microscopical examination of starch granules, Define Microscopical E...

Define Microscopical Examination of Starch Granules? Take a slide and make a thin film of a suspension of starch granules from different sources and examine under a microscope.

Lactation tetany of mares (eclampsia, Lactation tetany of mares (eclampsia,...

Lactation tetany of mares (eclampsia, transit tetany) Hypocalcaemia in mares causes lactation tetany, which is characterized by abnormal behaviour, in coordination and tetany.

Explain about the optic disc, Explain about the optic disc The optic di...

Explain about the optic disc The optic disc is also called a blind spot while the macula is referred to as the yellow spot. The ora serrata (the intersection between the retina

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