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What is the name of the wheat species with 42 chromosomes?
What is the name of the wheat species with 42 chromosomes?
In parapatric speciation, what is the fitness of hybrids in the contact zone compared to individuals on either side of the zone?
In parapatric speciation, what is the fitness of hybrids in the contact zone compared to individuals on either side of the zone?
What is a key innovation in adaptive radiation?
What is a key innovation in adaptive radiation?
What are mass extinctions characterized by?
What are mass extinctions characterized by?
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What is the primary factor contributing to the increasing rate of extinction?
What is the primary factor contributing to the increasing rate of extinction?
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What is the ploidy level of the T. turgidum (Emmer wheat) species?
What is the ploidy level of the T. turgidum (Emmer wheat) species?
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What is the ploidy level of the hybrid produced from crossing T. monococcum with T. tauschii?
What is the ploidy level of the hybrid produced from crossing T. monococcum with T. tauschii?
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What is the ploidy level of the T. tauschii species?
What is the ploidy level of the T. tauschii species?
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Based on the figure, which type of plant breeding process was likely used to create T. turgidum (Emmer wheat) from T. monococcum and wild T. tauschii?
Based on the figure, which type of plant breeding process was likely used to create T. turgidum (Emmer wheat) from T. monococcum and wild T. tauschii?
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Why is the hybrid produced from crossing T. monococcum and T. tauschii sterile?
Why is the hybrid produced from crossing T. monococcum and T. tauschii sterile?
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Which of the following is NOT a characteristic of sympatric speciation?
Which of the following is NOT a characteristic of sympatric speciation?
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What is the underlying mechanism driving the process of natural selection?
What is the underlying mechanism driving the process of natural selection?
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Which of the following is NOT a source of genetic variation within a population?
Which of the following is NOT a source of genetic variation within a population?
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What is a common mechanism for sympatric speciation in plants?
What is a common mechanism for sympatric speciation in plants?
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What is the Hardy-Weinberg Equilibrium used to describe?
What is the Hardy-Weinberg Equilibrium used to describe?
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Polyploidy often arises from:
Polyploidy often arises from:
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What does the term "descent with modification" refer to?
What does the term "descent with modification" refer to?
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Which of the following domesticated crops is an example of sympatric speciation?
Which of the following domesticated crops is an example of sympatric speciation?
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Which of the following is NOT a characteristic of a species as defined by the biological species concept?
Which of the following is NOT a characteristic of a species as defined by the biological species concept?
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In the process of wheat evolution, how many parent species were involved?
In the process of wheat evolution, how many parent species were involved?
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What is the primary mechanism by which new species arise?
What is the primary mechanism by which new species arise?
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Based on the information provided, what is the chromosome number of the Triticum turgidum species?
Based on the information provided, what is the chromosome number of the Triticum turgidum species?
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Which of the following is a key difference between allopatric and sympatric speciation?
Which of the following is a key difference between allopatric and sympatric speciation?
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Who is credited with proposing the Biological Species Concept?
Who is credited with proposing the Biological Species Concept?
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Which of the following would be considered a limitation of the Biological Species Concept?
Which of the following would be considered a limitation of the Biological Species Concept?
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Why is the hybrid (AB) in the wheat evolution example sterile?
Why is the hybrid (AB) in the wheat evolution example sterile?
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Which of the following is a postzygotic isolating mechanism?
Which of the following is a postzygotic isolating mechanism?
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What is the primary reason for a reduction in hybrid viability?
What is the primary reason for a reduction in hybrid viability?
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Which scenario exemplifies behavioral isolation?
Which scenario exemplifies behavioral isolation?
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What is the consequence of a reduction in gene flow between two populations?
What is the consequence of a reduction in gene flow between two populations?
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Which of the following can be a reason for reduced hybrid fertility?
Which of the following can be a reason for reduced hybrid fertility?
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What is the key event in the potential origin of a new species?
What is the key event in the potential origin of a new species?
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Which of these is an example of temporal isolation?
Which of these is an example of temporal isolation?
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Which of the following is NOT a prezygotic isolating mechanism?
Which of the following is NOT a prezygotic isolating mechanism?
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What is an example of a postzygotic isolating mechanism?
What is an example of a postzygotic isolating mechanism?
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What is the main difference between prezygotic and postzygotic isolating mechanisms?
What is the main difference between prezygotic and postzygotic isolating mechanisms?
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What is the main difference between allopatric and sympatric speciation?
What is the main difference between allopatric and sympatric speciation?
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What is a key characteristic of allopatric speciation?
What is a key characteristic of allopatric speciation?
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Which of the following is an example of allopatric speciation?
Which of the following is an example of allopatric speciation?
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What is a potential outcome of allopatric speciation?
What is a potential outcome of allopatric speciation?
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What is the role of islands in allopatric speciation?
What is the role of islands in allopatric speciation?
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Which of the following statements about allopatric speciation is TRUE?
Which of the following statements about allopatric speciation is TRUE?
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How can allopatric speciation occur on an archipelago?
How can allopatric speciation occur on an archipelago?
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Suppose a single species of bird colonizes an archipelago. What is the most likely outcome?
Suppose a single species of bird colonizes an archipelago. What is the most likely outcome?
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Study Notes
Evolution and Speciation
- Evolution is the descent with modification of species over time, driven by natural selection.
- Genetic variation is the basis of natural selection.
- Natural selection is the process where organisms with advantageous traits are more likely to survive and reproduce, passing those traits to their offspring.
- Variation arises through mutation and sexual recombination.
- Tracking alleles and genotypes across generations is key to understanding inheritance patterns (Mendelian genetics, Hardy-Weinberg Equilibrium).
- Genetic divergence leads to speciation.
- Speciation is the formation of new species through the splitting of existing ones.
- Darwin's On the Origin of Species revolutionized the understanding of evolutionary processes in the past 150 years, and new discoveries and technology continue to refine our understanding.
Species Concepts
- Species are groups of populations whose members have the potential to interbreed in nature to produce fertile offspring (biological species concept, proposed by Ernst Mayr).
- Species can't be defined by outward appearance alone.
- This concept does not apply to asexually reproducing species or extinct organisms.
Reproductive Isolation
- Reproductive isolating mechanisms prevent interbreeding among species.
- These mechanisms can arise from heritable differences in body form, function, or behavior.
- Prezygotic barriers prevent mating or fertilization.
- Postzygotic barriers reduce the viability or fertility of hybrid offspring.
Types of Reproductive Isolation
- Prezygotic Isolation Mechanisms
- Temporal isolation: different mating times (e.g., different seasons, or different times of day).
- Habitat isolation: different habitats (e.g., different ecosystems).
- Behavioral isolation: differing courtship rituals (e.g., dances in birds, songs).
- Mechanical isolation: incompatible mating structures (e.g., genital openings unsuitable for mating).
- Gametic isolation: incompatible gametes (e.g., sperm and egg cannot fuse).
- Postzygotic Isolation Mechanisms
- Reduced hybrid viability: reduced development or survival potential of offspring.
- Reduced hybrid fertility: viable but sterile offspring (e.g., mules).
- Hybrid breakdown: first-generation hybrids are viable and fertile, but later generations have reduced fitness.
Mechanisms of Speciation
- Speciation typically begins when gene flow between populations ends, causing distinct evolutionary paths.
- Allopatric speciation: speciation occurring with geographic isolation.
- Sympatric speciation: speciation occurring without geographic isolation; often involving genetic changes or polyploidy.
- Parapatric speciation: speciation occurring without complete geographic isolation, but with a gradation in environmental conditions impacting the population.
Adaptive Radiation
- Adaptive radiation: a burst of speciation when a lineage encounters new ecological niches.
- A key innovation allows a species to exploit a habitat in a new way thus driving evolution and speciation.
Extinction
- Extinction is the irrevocable loss of a species from Earth.
- Mass extinctions are periods of substantial extinctions followed by adaptive radiation events.
- Extinction is a natural process, but environmental pressures can accelerate it considerably.
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Description
This quiz covers key concepts in evolution, including natural selection, genetic variation, and speciation. Explore the processes that lead to the formation of new species and the impact of Darwin's work on evolutionary biology. Test your understanding of inheritance patterns and species concepts.
