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Questions and Answers
What does natural selection directly act upon?
What does natural selection directly act upon?
- Ecosystem balance
- Population size
- Genetic traits
- Observable characteristics (correct)
Which scenario best explains the process of natural selection?
Which scenario best explains the process of natural selection?
- Giraffes grow longer necks due to stretching in their lifetime.
- Long-necked giraffes survive better and reproduce more, gradually spreading the trait. (correct)
- Short-necked giraffes are genetically modified in a lab to have longer necks.
- Giraffes learn to use tools to reach higher leaves, reducing the need for long necks.
What happens to unfavourable genetic traits in a population over time according to natural selection?
What happens to unfavourable genetic traits in a population over time according to natural selection?
- They become more common.
- They become less common. (correct)
- They remain constant.
- They alternate in frequency.
Which of the following describes an example of a favourable trait within the giraffe population?
Which of the following describes an example of a favourable trait within the giraffe population?
According to Lamarck's theory, how would giraffes have developed long necks?
According to Lamarck's theory, how would giraffes have developed long necks?
What is gene flow?
What is gene flow?
What effect does gene flow have within a single population?
What effect does gene flow have within a single population?
How does gene flow affect speciation across populations?
How does gene flow affect speciation across populations?
How would the rate of gene flow typically compare in sedentary organisms versus more mobile organisms?
How would the rate of gene flow typically compare in sedentary organisms versus more mobile organisms?
What is non-random mating?
What is non-random mating?
How does non-random mating work against natural selection?
How does non-random mating work against natural selection?
What happens to a gene once it has been selected for by the environment?
What happens to a gene once it has been selected for by the environment?
What is natural selection described as in the provided content?
What is natural selection described as in the provided content?
What did Darwin theorize about the finches in the Galapagos Archipelago?
What did Darwin theorize about the finches in the Galapagos Archipelago?
Which factor selected for the different beak types in Darwin's finches?
Which factor selected for the different beak types in Darwin's finches?
Which example best illustrates an ecological niche based on the provided content?
Which example best illustrates an ecological niche based on the provided content?
What role do mutations play in the process observed in Darwin's finches?
What role do mutations play in the process observed in Darwin's finches?
What role does population size play in genetic drift?
What role does population size play in genetic drift?
What can overshadow natural selection in small populations?
What can overshadow natural selection in small populations?
Which of the following is NOT a cause of mutations?
Which of the following is NOT a cause of mutations?
In the marble analogy, what does the jar represent?
In the marble analogy, what does the jar represent?
How do favorable mutations affect an organism's likelihood of survival in a population?
How do favorable mutations affect an organism's likelihood of survival in a population?
What is the ultimate outcome of genetic drift in a small population given enough time?
What is the ultimate outcome of genetic drift in a small population given enough time?
Most mutations that occur in an organism are:
Most mutations that occur in an organism are:
During the marble analogy experiment, what does the replacement of each marble represent?
During the marble analogy experiment, what does the replacement of each marble represent?
What happened to the light-colored peppered moths during the Industrial Revolution?
What happened to the light-colored peppered moths during the Industrial Revolution?
Why does genetic drift have less impact on larger populations?
Why does genetic drift have less impact on larger populations?
Which of the following was NOT a consequence of the Industrial Revolution on the peppered moths?
Which of the following was NOT a consequence of the Industrial Revolution on the peppered moths?
Which scenario described best illustrates genetic drift?
Which scenario described best illustrates genetic drift?
What role do mutations play in evolutionary change?
What role do mutations play in evolutionary change?
What happens to the less common genetic outcomes in a population undergoing genetic drift?
What happens to the less common genetic outcomes in a population undergoing genetic drift?
What happens to an unfavorable mutation in a population?
What happens to an unfavorable mutation in a population?
Which term describes changes in the genetic material of an organism?
Which term describes changes in the genetic material of an organism?
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Study Notes
Agents of Evolutionary Change
- Five agents of evolutionary change: mutation, genetic drift, gene flow, non-random mating, and natural selection
Mutation
- Changes to the nucleotide sequence in the genetic material of an organism
- Caused by: errors in DNA replication, exposure to UV or radiation, mutagens, and viruses
- Creates variation in gene pools
- Most mutations are minor and do not impact an organism's fitness
- Mutations are the main provider of new traits for natural selection
Example: The Peppered Moth
- Evolution of the peppered moth due to pollution during the Industrial Revolution
- Light-colored moths died off, dark-colored moths flourished due to camouflage
Natural Selection
- Process by which environmentally favorable genetic traits become more common
- Acts on observable characteristics of an organism
- Favourable traits increase in frequency, unfavourable traits decrease
Example: The Giraffe
- Long-necked giraffes survived and reproduced due to favorable genetic traits
- Short-necked giraffes died off, leading to the emergence of long-necked giraffes
Evolution
- Natural selection leads to adaptations and specialization of organisms
- Can result in the emergence of new species over time
Example: The Finches
- Finches on the Galapagos Islands adapted to different food sources
- Different beak shapes emerged due to genetic variations and natural selection
Genetic Drift
- Random variations in which organisms reproduce, leading to changes in the genetic makeup of a population
- Depends on small population size
- Can overshadow natural selection in small populations
Analogy of Genetic Drift
- Randomly selecting marbles from a jar represents genetic drift
- Changes in the population's genetic makeup occur due to chance
Gene Flow
- Movement of genes from one population to another
- Increases genetic variation in a population
- Reduces the occurrence of speciation
Effects of Gene Flow on Evolution
- Introduces or reintroduces genes to a population
- Makes distant populations genetically similar
Non-Random Mating
- Mating that does not occur due to chance, but due to human interference
- Occurs when the possibility of mating is not the same for all possible pairs of individuals
- Works against natural selection
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