Which of the following is the most important precondition for speciation to occur?

(1) Reproductive isolation

(2) A crash of the population size

(3) Adaptive radiation

(4) Random mating

Subtopic:  Concept of Isolation |
 61%
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The ultimate source of allelic variations is:

1. Genetic recombinations 

2. Mutation 

3. Genetic drift 

4. Natural selection 

Subtopic:  Hugo De Vries Theory of Evolution |
 54%
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If a new allele suddenly becomes very abundant in a population, most likely it is:

1. mutating rapidly

2. flowing with emigrants

3. strongly selected for

4. a product of assortative mating

Subtopic:  Genetic Basis of Adaptation |
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Genetic drift occurs when a few individuals of a species colonize an island. This phenomenon is :

(1) the bottleneck effect

(2) the founder effect

(3) assortative mating

(4) random mating 

Subtopic:  Difference Between Drift & Selection |
 77%
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The unit of evolution is now known to be the:
1. individual
2. family
3. population
4. species

Subtopic:   A BRIEF ACCOUNT OF EVOLUTION |
 56%
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The struggle for existence is a consequence of:

(1) Each organism leaving more organisms than needed to replace itself

(2) Innate competitive tendencies

(3) The inevitable difficulty of coping with climatic conditions

(4) Territories and dominance hierarchies

Subtopic:  Darwin's Theory |
 51%
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Darwin believed that a giraffe has a long neck because:

1. a creator designed it that way

2. catastrophes eliminated short neck forms

3. its ancestors stretched their necks to get food

4. ancestral giraffes with longer necks got more food and left more surviving off-springs.

Subtopic:  Summary of Darwin's Theory |
 64%
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In a sympatric speciation, there is:

1. geographical isolation between groups of population
2. no geographical isolation between groups of population
3. reproductive isolation of a subpopulation in the midst of the parent population 
4. geographical isolation bout no reproductive isolation
Subtopic:  Concept of Speciation |
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In modern terms, selection refers to :

1. Inheritance of dominant characters
2. differential reproduction 
3. a decrease in allele frequency in a population
4. differences in the contribution of various genotypes to the next generation 

Subtopic:  Summary of Darwin's Theory |
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In genetic drift, the term "genetic bottleneck" means:

1. reduction in allele frequencies or richness

2. random change in allele frequency by chance alone

3. sudden increase in the number of individuals

4. reproductive isolation of the population

Subtopic:  Sources of Variation: 2 | Sources of Variation |
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