How was the mechanism of sympatric speciation among hemp nettles in nature verif

Question

How was the mechanism of sympatric speciation among hemp nettles in nature verified experimentally? O a. By producing experimental hybrids that formed fertile offspring with the naturally occurring hybri O b. By producing hybrids that were 98% fertile under laboratory conditions O c. By simply creating unique hybrids under laboratory conditions O d. By producing experimental hybrids that could reproduce successfully with both parent species O e. By creating hybrids that reproduced through the Fa generation before dying from hybrid inviability

Explanation / Answer

1st QUESTION ANSWER

IS OPTION e: by creating hybrids that reproduced through the F4 genation before dying from hybrid inviability.

explanation:

THE MECHANISM OF SYMPATRIC SPECIATION HAS BEEN VERIFIED FORMANY PLANTS.

ONE EXAMPLE IS A GROUP OF SPECIES,COLLECTIVELY CALLED HEMP NEETLES,THAT OCCURS IN TEMPERATE PARTS OF EUROPE AND ASIA.

ONE HEMP NEETLE,GALEOPSIS tetrahit ( 2n =32 ),IS A NATURALLY OCCURING ALLOPOLYPLOID THOUGHT TO HAVE FORMED BY THE HYBRIDIZATION OF TWO SPECIES,GALEOPSIS pubescens ( 2n = 16) and GALEOPSIS speciosa ( 2n= 16).THIS PROCESS OCCURED IN NATURE BUT WAS EXPERIMENTALLY REPRODUCED.GALEOPSIS pubescens and GALEOPSIS speciosa WERE CROSSED TO PRODUCE F1 HYBRIDS,MOST OF WHICH ARE STERILE.NEVERTHLESS,BOTH F2 AND F3 GENERATIONSWERE PRODUCED. THE F3 GENERATION INCLUDED A POLYPLOID PLANT WITH 2n =32 THAT SELF FERTILIZED TO YIELD FERTILE F4 OFFSPRING THAT COULD NOT MATE WITH EITHER OF THE PARENTAL SPECIES.THESE ALLOPOLYPLOID PLANTS HAD THE SAME APPEARANCE AND CHROMOSOME NUMBER AS THE NATURALLY OCCURING GALEOPSIS tetrahit. WHEN THE EXPERIMENTALLY PRODUCED PLANTS PLANTS WERE CROSSED WITH NATURALLY OCCURING G.tetrahit, A FERTILE F1 GENERATION WAS FORMED.THUS THE EXPERIMENT DUPLICATED THE SPECIATION PROCESS THAT OCCURED IN NATURE.

2nd QUESTION

ANSWER IS c:artificial selection

ARTIFICIAL SELECTION HELPS TO PRODUCE ORGANISMS WITH DESIRED TRAIT OR COMBINATION OF TRAITS.THIS METHOD ALSO EXPLAINS THATDIFFERENT LOOKING STRUCTURES CAN EVOLVE FROM SAME ORIGIN. FOR, EXAMPLE,DIFFERENT VEGETABLES ARE EVOLVED FROM WILD CABBAGE. SOME FARMERS WANTED TO SELECT FOR VERY SHORT DISTANCES BETWEEN LEAVES,AND HAVE BRED THE CABBAGE WE EAT.SOME WANT TO SELECT FOR ARREST FLOWER DEVELOPMENT,AND HAVE BRED BROCOLI, OR FOR STERILE FLOWERS HAVE MADE CAULIFLOWER.SO,CABBAGE,CAULIFLOWER,BROCOLI,KOHLRABI AND KALE ARE DESCENDED FROM SAME ANCESTOR,WILD CABBAGE BY ARTIFICIAL SELECTION.

3RD QUESTION

answer is b:interbreed

THE BIOLOGICAL SPECIES CONCEPT IS THE MOST WIDELY ACCEPTED SPECIES CONCEPT IN TERMS OF INTERBREEDING.

ERNST MAYR DEFINED SPECIES AS :

SPECIES ARE GROUP OF INTERBREEDING NATURAL POPULATIONS THAT ARE REPRODUCTIVELY ISOLATED FROM OTHER SUCH GROUPS.

4TH QUESTION

ANSWER IS OPTION b: 2

DISRUPTIVE OR DIVERSIFYING SELECTION, DESCRIBES CHANGES IN POPULATION GENETICS IN WHICH EXTREME VALUES FOR A TRAIT FAVOURED OVER INTERMEDIATE VALUES.

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