14.1 The origin of species is the source of biological diversity

14.1 The origin of species is the source of biological diversity

Ch. 14 The Origin of Species Copyright 2009 Pearson Education, Inc. The origin of species is the source of biological diversity Speciation is the emergence of new species

Every time speciation occurs, the diversity of life increases Copyright 2009 Pearson Education, Inc. There are several ways to define a species The biological species concept defines a species as a population or group of populations whose members

have the potential to interbreed in nature and produce fertile offspring Reproductive isolation prevents gene flow and maintains separate species Copyright 2009 Pearson Education, Inc. Reproductive barriers keep species separate Reproductive barriers serve to isolate a species gene pool and prevent interbreeding

Reproductive barriers are categorized as prezygotic or postzygotic, depending on whether they function before or after zygotes form Copyright 2009 Pearson Education, Inc. Reproductive barriers keep species separate Prezygotic Barriers In habitat

isolation, two species live in the same general area but not in the same kind of place Copyright 2009 Pearson Education, Inc.

Reproductive barriers keep species separate Prezygotic Barriers In mechanical isolation, female and male sex organs are not compatible Copyright 2009 Pearson Education, Inc.

Reproductive barriers keep species separate Prezygotic Barriers In behavioral isolation, there is little or no sexual attraction between species, due to

specific behaviors Reproductive barriers keep species separate Prezygotic Barriers In gametic isolation, female and male gametes are not compatible

Reproductive barriers keep species separate Postzygotic Barriers Postzygotic barriers operate after hybrid zygotes are formed In reduced hybrid viability, most hybrid offspring do not survive In reduced hybrid fertility, hybrid offspring are vigorous but sterile The process of speciation depends on whether reproductive barriers prevent gene flow between populations

Copyright 2009 Pearson Education, Inc. MECHANISMS OF SPECIATION Copyright 2009 Pearson Education, Inc. In allopatric speciation, geographic isolation leads to speciation In allopatric speciation, populations of the same species

are geographically separated, separating their gene pools Changes in the allele frequencies of each population may be caused by natural selection, genetic drift, and mutation, unaffected by gene flow from other populations Gene flow between populations is initially prevented by a geographic barrier The Grand Canyon and Colorado River separate two species of antelope squirrels

Copyright 2009 Pearson Education, Inc. A. harrisi South A. leucurus North

In sympatric speciation, speciation takes place without geographic isolation In sympatric speciation, new species may arise within the same geographic area as a parent species Gene flow between populations may be reduced by factors such as polyploidy, habitat differentiation Copyright 2009 Pearson Education, Inc.

Recently Viewed Presentations

  • POST-18 CAREER OPTIONS IN A HARSH NEW WORLD A menu approach ...

    POST-18 CAREER OPTIONS IN A HARSH NEW WORLD A menu approach ...

    … and is now . Communities Manager . for . innocent smoothies. She manages their . SOCIAL MEDIA STRATEGY "I spend my days tweeting for @innocent" It's a key role in modern business, needing a cutting edge ability to analyse...
  • The Wonderful World of Winter Camping

    The Wonderful World of Winter Camping

    Nature activities in your local town Community Resources & Activities More Fun Activities Indoor Climbing Rafting, Canoeing & Water Activities Hiking & Backpacking Hiking & Backpacking CT State Parks & Forests Appalachian Trail in CT Appalachian Trail in CT Overnight...
  • Kawasaki Disease - Тдму

    Kawasaki Disease - Тдму

    Kawasaki disease is a group of specific symptoms and physical signs. Kawasaki disease is associated with swelling and damage of the blood vessels, or arteries. This swelling and damage is called inflammation. Kawasaki disease often affects the arteries that supply...
  • How to Register - Arbiter

    How to Register - Arbiter

    Step Seven: Click case ruling to see how it relates in the case book without leaving the rulebook view
  • Tables - Airbus

    Tables - Airbus

    Tables. DD MONTH YEAR. Presentation title runs here (go to Header and Footer to edit this text)
  • NMS presentation (September 2011) - PSNC Main site

    NMS presentation (September 2011) - PSNC Main site

    LMCs and LPCs are ideally placed to make this happen." The BMA viewpoint Dr Clare Gerada, Chair of the Royal College of General Practitioners "Patients do sometimes experience problems with their medicines and, through the New Medicine Service, GPs and...
  • Models of STI Driven Manufacturing Dr. Nirmalya Bagchi

    Models of STI Driven Manufacturing Dr. Nirmalya Bagchi

    Start up led manufacturing growth: Israel. Israel is a start up nation. Produces more start ups than Japan, China, India, Korea, Canada and UK. Attracts 30 times more venture capital investment than Europe
  • The Original Divine Principle - tongil.org

    The Original Divine Principle - tongil.org

    The Original substance of Divine Principle