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Questions and Answers
Which of the following are mechanisms of evolution? (Select all that apply)
Which of the following are mechanisms of evolution? (Select all that apply)
- Genetic drift (correct)
- Mutation (correct)
- Sexual selection (correct)
- Natural selection (correct)
- Gene flow (correct)
What is the term for the differential reproductive and survival of genotypes?
What is the term for the differential reproductive and survival of genotypes?
Natural selection
What is defined as individual males or females having a slight advantage over others and transmitting that advantage to their offspring?
What is defined as individual males or females having a slight advantage over others and transmitting that advantage to their offspring?
Sexual selection
What is the net movement of alleles in or out of a population called?
What is the net movement of alleles in or out of a population called?
What term describes the changes in gene frequency in a population due to random chance, particularly in small populations?
What term describes the changes in gene frequency in a population due to random chance, particularly in small populations?
Who conducted an experiment with E.coli to test natural selection and what year was it?
Who conducted an experiment with E.coli to test natural selection and what year was it?
What methods were used by Richard Lenski in his E.coli experiments?
What methods were used by Richard Lenski in his E.coli experiments?
What were the results of Lenski's E.coli study?
What were the results of Lenski's E.coli study?
What is the significance of Lenski's findings regarding E.coli?
What is the significance of Lenski's findings regarding E.coli?
Who performed a study on E.coli consuming glycerol and what were their methods?
Who performed a study on E.coli consuming glycerol and what were their methods?
What were the results of Paulsson's experiments?
What were the results of Paulsson's experiments?
What does epistasis refer to?
What does epistasis refer to?
What is the competitive exclusion principle?
What is the competitive exclusion principle?
Who conducted the 29-year study of two finch species on Daphne Island?
Who conducted the 29-year study of two finch species on Daphne Island?
What were the results of the Grant study on finches?
What were the results of the Grant study on finches?
What was the significance of the Grant study?
What was the significance of the Grant study?
What does heritability refer to?
What does heritability refer to?
What is the importance of field studies on mechanisms of evolution?
What is the importance of field studies on mechanisms of evolution?
What type of evolution results from competition and geographic variation?
What type of evolution results from competition and geographic variation?
What is the relationship of species living in different geographic zones called?
What is the relationship of species living in different geographic zones called?
How is the relationship of species sharing a geographic area defined?
How is the relationship of species sharing a geographic area defined?
What is stabilizing selection?
What is stabilizing selection?
What is directional selection?
What is directional selection?
What does disruptive selection entail?
What does disruptive selection entail?
Match the following types of selection with their definitions:
Match the following types of selection with their definitions:
What are the forms of sexual selection?
What are the forms of sexual selection?
What is an example of sexual selection in dung beetles?
What is an example of sexual selection in dung beetles?
What do dunnocks do to prevent monopolization by one male?
What do dunnocks do to prevent monopolization by one male?
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Study Notes
Mechanisms of Evolution
- Natural selection enhances survival and reproduction of advantageous genotypes.
- Sexual selection allows individuals with traits favored by mates to pass those traits to their offspring.
- Mutation introduces new genetic variations in a population.
- Gene flow refers to the movement of alleles between populations, influencing genetic diversity.
- Genetic drift leads to changes in allele frequencies, especially significant in small populations, and includes the founder effect.
Richard Lenski's E. coli Experiment
- Conducted in 1988, challenging E. coli with feast and famine cycles to observe evolutionary changes.
- E. coli was placed in 12 flasks at body temperature, alternating between feeding and starvation.
- Results showed increased growth rates and size, with different mutations emerging in each bacterial line.
- Notably, one line developed the ability to metabolize citrate for energy, enhancing survival.
Bernhard Paulsson's Glycerol Study
- Investigated the effects of feeding E. coli glycerol, a non-traditional food source.
- Bacteria demonstrated quicker growth; genome sequencing revealed critical gene mutations.
- Some genes required the presence of other mutations to enhance growth, indicating collaborative gene interactions.
Epistasis
- Describes how the effects of one gene are influenced by one or more other genes, altering overall phenotypic expression.
Competitive Exclusion Principle
- Suggests that new species must exploit unique ecological niches to coexist without direct competition.
Peter and Rosemary Grant's Finch Study
- Conducted a 29-year analysis of finch species on Daphne Island, observing changes in mean body size and beak shape related to environmental conditions.
- Results confirmed that adaptations are heritable and that evolutionary changes can be unpredictable.
Heritability
- Refers to the proportion of variability in a population that results from genetic differences, crucial for understanding evolutionary dynamics.
Importance of Field Studies
- Field studies provide vital insights that bridge microevolutionary changes with broader macroevolutionary patterns.
Types of Evolutionary Relationships
- Character displacement arises from competition and geographical variation between species.
- Allopatric speciation occurs when species are isolated geographically.
- Sympatric speciation involves species living in shared geographic areas.
Types of Natural Selection
- Stabilizing selection favors average phenotypes and preserves characteristics, such as human birth weight.
- Directional selection favors individuals with traits varying in one direction, observed in longhorn cattle horn development.
- Disruptive selection favors extreme traits, as seen in the beak sizes of finch species on Santa Cruz Island.
Forms of Sexual Selection
- Involves male-male competition and female choice influencing mating success.
- Male dung beetles can sneak around competitors, while female dunnocks mate with multiple males, promoting diverse mating outcomes.
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