Speciation, Biology

Assignment Help:

SPECIATION -

  • Origin of new species: An isolated population of a species independently develops different types of mutations.
  • The later accumulate in its gene pool. After several generations, the isolated population becomes genetically and reproductively different from others so as to constitute a new species.
  • The million of different species that exist today did not emerge by any single sequence of events but have come into existence by following types different paths of speciation.

1.       PHYLECTIC SPECIATION -

  • Darwin entitled his great book.
  • For Darwin, speciation was the simple, gradual accumulation of changes in a lineage throughout time, until the group was distinct enough to be considered a new species. This process is now called phyletic speciation.

2.       ALLOPATRIC SPECIATION -

  • It is considered as the most common type of speciation.
  • Allopatric speciation typically occurs when a physical barrier i. e., a mountain range, a river, or an oil pipeline, geographically separates a population from its parental population.
  • E.g., Different species of Darwin finches in the Galapagos Island.

3.       SYMPATRIC SPECIATION -

  • Sympatric speciation occurs in populations where individuals continue to live among one another, even though some type of biological difference, such as the time of the year when gonads mature, has divided the members into different reproductive groups.
  • The best accepted cases of sympatric speciation occur in plants as a result of polyploidy, an increase in the number of sets of chromosomes per cell occurs.

4.       PARAPATRIC SPECIATION -

  • Parapatric speciation is thought to occur in populations that lie adjacent to one another.
  • Gene pools diverge because the environment varies sufficiently in the different localities.
  • As a result, different traits are selected in each population.

Related Discussions:- Speciation

Importance value index (ivi) - synthetic characters, Importance Value Index...

Importance Value Index (IVI) - Synthetic Characters In any study of community, the quantitative value of each of the frequency density, and cover has its own importance. But t

What are the luria''s methods and theories, What are the Luria's methods an...

What are the Luria's methods and theories Adhering to our theory that the Luria Nebraska bears little resemblance to Luria's methods and theories, there seems little point in i

What is the photoperiod, What is the photoperiod? The Photoperiod is th...

What is the photoperiod? The Photoperiod is the daily time period of light exposure of a living being and the photoperiod may differ according to the period of the year.

Role of chemical factors in controlling apical dominance, Role of Chemical ...

Role of Chemical Factors in Controlling Apical Dominance There were indications about the existence of plant hormones in the last part of 19th century. The plant hormones had

Disposal-lab animals, Disposal : Opaque bags are the recommended for dispo...

Disposal : Opaque bags are the recommended for disposing off carcasses. You should also put freshly dissected animals and tissues into opaque plastic bags, seal them and dispose t

Define types of circulatory systems, Q. What are the two kinds of circulat...

Q. What are the two kinds of circulatory systems? The circulatory systems can be classified into closed circulatory system and open circulatory system.

Describe airway and respiratory support in heart disease, Describe Airway a...

Describe Airway and Respiratory Support in the Newborn ? Like in any other emergency situation a stable airway needs to be established first. Newborns with severe respiratory d

Three main types of trophic pyramids studied in ecology, What are the three...

What are the three main types of trophic pyramids studied in Ecology? The three kinds of trophic pyramids studied in Ecology are the numeric pyramid, the biomass pyramid and th

Binomial nomenclature, collection of different animals,human being and inse...

collection of different animals,human being and insects stages of binomial nomenclature

State the posterior superior alveolar nerve, Posterior superior alveolar ne...

Posterior superior alveolar nerve and vessels It is found in the  posterior aspect of the maxilla running between the bone and the lining of the maxillary sinus may be injured

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