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BIOL 1000 Lecture Notes - Lecture 49: Allopatric Speciation, Allele Frequency, Genetic Drift

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erinchimpanzee657

13 May 2017

School

University of Manitoba

Department

Biological Sciences

Course

Professor

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Document Summary

Signals that attract mates and elaborate mating behaviours that are unique to a species are the most important reproductive barriers. E. g. only recognizing firefly light signals of one"s own kind : 4) mechanical isolation female and male sex organs are not compatible, gametic isolation sperm of one species may not be able to fertilize eggs of another. Postzygotic barriers = operate after hybrid zygotes have formed : most hybrid offspring do not survive, reduced hybrid fertility hybrid offspring reach maturity and are vigorous but sterile. E. g. a mule is a robust but sterile offspring of a female horse & a male donkey . Cannot produce offspring: hybrid break-down first generation hybrid offspring are viable and fertile, but when these hybrids mate with each other, offspring are feeble/sterile. In allopatric speciation, geographic isolation leads to speciation. Key event in origin of new species is the speciation of a population from other populations of the same species .

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Related Questions

2 Genetics -Match the terms with the most suitable description.
(Points : 16)

Potential Matches:

: An allele that can be expressed byan individual that is heterozygous.

: The genetic make-up of anindividual.

: The control of more than onephenotypic character by a single gene.

: The visible physical expression ofan individual's genetic make-up.

: An allele that can only beexpressed when an individual is homozygous.

: A trait controlled by more thanjust a single pair of alleles.

: A trait controlled by a genelocated on either the X or Y chromosomes.

: An individual carrying only oneallele of a recessively inherited disorder.

3. Evolution- Match the terms with the most suitable description.
(Points : 16)

Potential Matches:

1 : hybrid sterility

2 : habitat isolation

3 : hybrid inviability

4 : geographic isolation

5 : mechanical isolation

6 : gamete mortality

7 : temporal isolation

8 : behavioral isolation

: Because of a single mutation in adevelopmental gene, two closely related species of wasps have aslightly different anatomy of their sex organs making interbreedingimpossible.

: Two species of snakes aremorphologically very similar but breed during differentseasons.

: Two similar species of treehopperslive and feed on two separate species of trees.

: Males of two species of birds usedifferent mating dances to attract their mates.

: Due to a geographic barrier, asmall portion of a population remains isolated and its gene pooldiverges from that of the original population.

: Sperm from a male of one speciesdies in the reproductive tract of the female of a different speciesbefore fertilization can occur

: Mules are a cross between a donkeyand a horse; they are viable, healthy animals, but they cannotreproduce.

: A cross between two species ofsalamanders yields offspring, but they do not survive long enoughto reproduce

periwinkledeer332

1. Biomes - Match the biome with itsdescription.

Potential Matches:

1 : Coniferous forest

2 : Temperate forest

4 : Tropical rainforest

: Caribou, musk ox and lemmingsare common, along with permafrost, mosses and lichens.

: May be hot or cold, but alwaysvery dry.

: Long snowy winters and shortsummers allow for cone-bearing evergreen trees to flourish.

: Spectacular displays of colorin the fall occur before deciduous trees drop their leaves.

: Plentiful rainfall and warmyear round temperatures produce a habitat home to the greatestdiversity of plants and animals.

: Mostly treeless expanse knownfor large herds of grazing mammals.

: Home to migrating waterfowl,this type of biome is important in reducing flooding and improvingwater quality.

: Transition area between a riverand an ocean with salinity ranging from nearly that of freshwaterto that of the oceans.

2 Genetics - Match the terms with the mostsuitable description.
(Points : 16)

Potential Matches:

: An allele that can be expressedby an individual that is heterozygous.

: The genetic make-up of anindividual.

: The control of more than onephenotypic character by a single gene.

: The visible physical expressionof an individual's genetic make-up.

: An allele that can only beexpressed when an individual is homozygous.

: A trait controlled by more thanjust a single pair of alleles.

: A trait controlled by a genelocated on either the X or Y chromosomes.

: An individual carrying only oneallele of a recessively inherited disorder.

3. Evolution - Match the terms with the mostsuitable description.
(Points : 16)

Potential Matches:

1 : hybrid sterility

2 : habitat isolation

3 : hybrid inviability

4 : geographic isolation

5 : mechanical isolation

6 : gamete mortality

7 : temporal isolation

8 : behavioral isolation

: Because of a single mutation ina developmental gene, two closely related species of wasps have aslightly different anatomy of their sex organs making interbreedingimpossible.

: Two species of snakes aremorphologically very similar but breed during differentseasons.

: Two similar species oftreehoppers live and feed on two separate species of trees.

: Males of two species of birdsuse different mating dances to attract their mates.

: Due to a geographic barrier, asmall portion of a population remains isolated and its gene pooldiverges from that of the original population.

: Sperm from a male of onespecies dies in the reproductive tract of the female of a differentspecies before fertilization can occur

: Mules are a cross between adonkey and a horse; they are viable, healthy animals, but theycannot reproduce.

: A cross between two species ofsalamanders yields offspring, but they do not survive long enoughto reproduce