30 Questions
Which factor makes the impact of natural selection apparent over time?
Environmental change
What is the term used to describe a group of individuals of the same species that interbreed?
Gene pool
In what scenario does microevolution occur?
When there are changes in the relative frequencies of alleles in a population
What remains constant within a gene pool unless other factors are at play?
Allele frequencies
What can enhance an individual's reproductive success in some cases?
A mutated allele
Which term describes the situation where different populations of the same species do not exchange genetic material?
Geographic isolation
What is the main purpose of the Hardy-Weinberg equation?
To test whether evolution is occurring in a population
Which of the following conditions is NOT necessary for the Hardy-Weinberg equilibrium?
Mutations occurring frequently
What is the impact of genetic drift on allele frequencies in a population?
Genetic drift causes allele frequencies to fluctuate unpredictably
How does gene flow contribute to genetic variation within a population?
Gene flow introduces new alleles into a population
Which of the following is NOT a main cause of evolutionary change?
Mutation rate
In terms of allele frequencies, what does nonrandom mating usually have little impact on?
Allele frequencies
What is the ultimate source of genetic variation that serves as the raw material for evolution?
Mutation
What did Darwin struggle to explain in 'The Origin of Species' regarding individual organisms?
Variation among individuals
Which scientist made a significant contribution to the understanding of inheritance in pea plants just a few years after Darwin's 'The Origin of Species' was published?
Gregor Mendel
Which interaction is essential for evolution to occur, involving elements like chance, natural selection, and the environment?
Mutation and sexual reproduction
What can have a significant effect on an organism's phenotype with just a small change, such as altering a single nucleotide in a protein-coding gene?
Mutation
Why are adaptations often characterized as compromises in evolution?
As the same structure may perform multiple functions
What genetic phenomenon tends to reduce differences between populations?
Gene flow
Which situation could lead to a loss of genetic diversity due to a population being greatly reduced?
Bottleneck effect
In a founder effect, what kind of individuals typically establish a new population in an island or new habitat?
A few individuals
Which domain includes organisms like Bacteria and Archaea?
Prokaryotes
What is the main contributor to the establishment of relatively high frequencies of inherited disorders in some human populations?
Founder effect
How can human activities, like overhunting and habitat destruction, impact genetic diversity?
Lead to the bottleneck effect
What is the main driving force behind the accumulation of favorable traits in a population over many generations?
Differential survival and reproduction
What aspect of natural selection does the statement 'Natural selection is more of an editing process than a creative mechanism' emphasize?
The limitation to existing variations
Why can natural selection not 'fashion perfect organisms'?
As it can only work with existing genetic variations
Which factor is essential for natural selection to operate on a population?
Genetic diversity within the population
What does the statement 'Selection can act only on existing variations' imply about the process of natural selection?
It is limited by the gene pool of the population
What is the primary mechanism through which accumulated favorable traits spread in a population?
Differential reproductive success
Study Notes
Evolution's Limitations and Mechanisms
- Evolution is limited by historical constraints and co-opts existing structures to adapt to new situations.
- Adaptations are often compromises, and the same structure often performs many functions.
- Chance, natural selection, and the environment interact, and environments often change unpredictably.
Genetic Variation and Mutation
- Mutation is the ultimate source of genetic variation, which is the raw material for evolution.
- Changes in the nucleotide sequence of DNA result in new alleles, and a single nucleotide change can have a significant effect on phenotype.
Hardy-Weinberg Equilibrium
- The Hardy-Weinberg equation can be used to test whether evolution is occurring in a population.
- The 5 conditions for the Hardy-Weinberg equilibrium are:
- A very large population
- No gene flow between populations
- No mutations
- Random mating
- No natural selection
- These conditions are rarely met in real populations, resulting in changes to allele and genotype frequencies.
Microevolution and Population Evolution
- Evolution occurs within populations, which are groups of individuals of the same species that live in the same area and interbreed.
- Different populations of the same species may be geographically isolated from each other, leading to genetic differences.
- Microevolution refers to the change in the relative frequencies of alleles in a population over a number of generations.
- The gene pool consists of all copies of every type of allele in a population.
Genetic Drift
- Genetic drift is the random change in allele frequencies over time, which can lead to a loss of genetic diversity.
- The bottleneck effect and founder effect are types of genetic drift that result from population reduction or colonization.
Domain System and Diversity
- Biologists recognize a 3-domain system: Bacteria, Archaea, and Eukarya.
- Diversity exists among fungi, plants, and animals, as well as invertebrates and vertebrates.
Natural Selection
- Natural selection is the process by which individuals with favorable traits are more likely to survive and reproduce, leading to the accumulation of these traits in the population.
- Natural selection cannot fashion perfect organisms and is limited by time and place.
- Scientists can observe natural selection in action, such as in the development of pesticide resistance in insects.
Explore the concept of how evolution occurs within populations and the impact of natural selection on a population's changes over time. Learn about how a mutated allele can improve an individual's adaptation in changing environments.
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