30 Questions
What are the consequences of mutations on phenotypes?
Mutations can either be neutral, cause lethal diseases, or affect phenotypes differently.
How does genetic recombination occur during sexual reproduction in humans?
One member of each chromosome pair is shuffled randomly into each egg and sperm.
What factor increases genetic variation by picking up a 'new' gene?
Lateral gene transfer
What primarily determines the number of phenotypes for a given trait?
The number of genes controlling the trait
How can natural selection affect single-gene traits?
By producing changes in phenotype frequencies through changes in allele frequencies
Which is NOT a way that reproductive isolation can develop?
Habitat Isolation
What is the primary result of reproductive isolation between two populations?
Complete cessation of gene flow between the populations
Which isolation occurred due to differences in courtship rituals in Darwin’s finches?
Behavioral Isolation
Which effect describes a change in allele frequencies due to the migration of a small subgroup?
Founder Effect
What type of isolation occurs when species reproduce at different times?
Temporal Isolation
Which event is considered the initial step leading to speciation in the Galapagos finches?
Founders Arrival
What can result in a dramatic reduction in genetic diversity?
Genetic Bottlenecks
In which scenario is genetic equilibrium achieved?
When allele frequencies are not changing
Which of the following best describes polygenic traits?
Traits controlled by two or more genes
Which phenomenon can occur in small populations leading to changes in allele frequency by chance?
Genetic Drift
What does the gene pool of a population consist of?
All genes present in the population
Which statement best describes how allele frequency changes in a population over time?
Evolution involves any change in allele frequency over time.
What does natural selection act upon in an organism?
Its phenotype only
Which of the following is NOT a source of genetic variation?
Inbreeding
Which activities are directly responsible for generating variation in chromosomes?
Recombination during sexual reproduction
What role do Hox genes play in the development of an embryo?
Determine which side of an embryo grows the different body parts
How does genetic rearrangement influence eukaryotic cells?
It makes eukaryotic cells more complex
What factor contributed to the adaptation and natural selection of birds in the Galapagos Islands?
A different environment on the islands
Which factor influenced the mutation variations among birds from different islands in the Galapagos?
How plants produced their nuts
What is the purpose of a molecular clock in genetic studies?
To estimate the time that two species have been evolving independently
Why did birds from different islands in the Galapagos exhibit behavioral isolation?
They would not mate with each other due to beak size preferences
What can small changes in Hox gene activity during the embryological stage cause?
Big changes in adult animals
What is the significance of 'ticks' in the context of molecular clocks?
They help identify how many mutations happen in a human body
How does the degree of specialization in birds impact competition for resources?
More specialized birds face less competition
What is one way new genes can evolve according to molecular evolution?
Duplication and modification of existing genes
Study Notes
Genes and Variations
- Genetic information is stored in chromosomes, which generate variation
- A gene pool consists of all genes present in a population
- Allele frequency is the number of times an allele occurs in a gene pool as a percentage of the total alleles for that gene
- Evolution involves any change in allele frequency in a population over time
- Genotype refers to an organism's genetic makeup, while phenotype refers to its physical characteristics
Sources of Genetic Variation
- Mutation: a heritable change in genetic information
- Genetic recombination during sexual reproduction: shuffling of genes during meiosis
- Lateral gene transfer: gene flow can increase genetic variation and introduce new genes
Single-Gene and Polygenic Traits
- Single-gene traits: controlled by one gene
- Polygenic traits: controlled by two or more genes
- Natural selection on single-gene traits can produce changes in allele frequencies reflected in phenotype frequencies
Genetic Drift and Bottlenecks
- Genetic drift: random change in allele frequency in small populations
- Founder effect: allele frequencies change due to migration of a small subgroup
- Genetic bottleneck: reduction in genetic diversity due to a dramatic decrease in population size
Speciation and Isolating Mechanisms
- Reproductive isolation: when two populations stop interbreeding altogether
- Behavioral isolation: differences in courtship rituals or behaviors
- Geographic isolation: separation by geographic barriers
- Temporal isolation: reproduction at different times
- Speciation in Darwin's finches: geographic isolation, changes in gene pool, behavioral isolation, and ecological competition
Molecular Evolution
- New genes can evolve through duplication and modification of existing genes
- Gene duplication: copy of a gene can mutate and take on a new function
- Genetic rearrangement: chromosomes can break and reconnect, acquiring new sequences of DNA
Developmental Genes and Body Plans
- Hox genes determine the body plan of an embryo
- Small changes in hox gene activity during embryological stage can produce big changes in adult animals
Molecular Clocks and Neutral Mutations
- Molecular clock: uses mutation rates in DNA to estimate time of independent evolution
- Ticks: measure the number of mutations that occur in a human body over time
This quiz covers the fundamentals of population evolution, including genes, variations, heritable traits, chromosomes, and allele frequency. Understand how genetic definitions shape species and populations.
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