Genetics and Evolution Quiz

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Questions and Answers

What is the general consequence of large mutations in organisms?

They can cause the organism to die off. (correct)

They are often retained through natural selection.

They contribute to the gradual accumulation of small changes.

They usually lead to beneficial adaptations.

Why are small mutations more likely to be beneficial?

They alter the entire genetic framework of the species.

They typically lead to immediate extinction.

They cause drastic changes in the organism.

They result in gradual changes allowing adaptation. (correct)

How do microbes differ in their mutation processes compared to larger organisms?

They only change individual base pairs.

They only undergo gradual mutations.

They are not affected by environmental factors.

They frequently acquire large blocks of genetic material. (correct)

What role does natural selection play in regards to mutations?

It primarily acts on beneficial mutations with small effects. Signup and view all the answers

What is a common example of beneficial genetic material transfer in microbes?

Spread of antibiotic resistance. Signup and view all the answers

Which mechanism leads to reproductive isolation due to differences in flowering time among populations?

Temporal isolation Signup and view all the answers

What process results in genetic isolation due to a shift in habitat for organisms?

Peripatric speciation Signup and view all the answers

Which form of reproductive isolation arises from physical incompatibility in mating structures?

Mechanical isolation Signup and view all the answers

How does sexual selection contribute to reproductive isolation?

By leading to differences in mating preferences and strategies Signup and view all the answers

Which of the following is NOT a form of reproductive isolation?

Natural selection isolation Signup and view all the answers

What is the primary reason mammals evolve reproductive isolation faster than other taxa?

Mammals experience significant immunological changes during pregnancy Signup and view all the answers

How quickly can reproductive isolation be achieved in mammals?

A maximum of 3 million years Signup and view all the answers

Why do mammals have a low tolerance for hybridization?

Pregnancy may fail due to the genetic differences in hybrids Signup and view all the answers

In which group is hybrid viability more common compared to mammals?

Birds Signup and view all the answers

What is a consequence of mammals being able to carry a genetically different fetus?

They may experience more infections during pregnancy Signup and view all the answers

What term describes the process where an animal learns to associate a specific sound with feeding time?

Classical conditioning Signup and view all the answers

Which type of learning involves solving problems without the use of trial and error?

Insight learning Signup and view all the answers

Which of the following organisms is noted for using tools and exhibiting problem-solving skills?

Crows Signup and view all the answers

What concept explains the ability of an organism's genes to express different phenotypes based on varying environmental conditions?

Adaptive phenotypic plasticity Signup and view all the answers

How does natural selection enhance adaptation in organisms?

By favoring mutations that enhance survival in changing environments Signup and view all the answers

In which scenario is insight learning best illustrated?

A crow bending a straight wire to retrieve food Signup and view all the answers

Which of the following is NOT a characteristic of complex cognition in animals?

Reliance solely on trial and error Signup and view all the answers

What does natural selection NOT guarantee?

Perfection in organisms Signup and view all the answers

What is a primary factor for a population to develop traits that enhance the ability to secure mates?

Variation in phenotype must be present. Signup and view all the answers

Which mating system allows for the highest variation in mating success?

Polygyny Signup and view all the answers

In sexual selection, which statement is true regarding male competition?

Males compete primarily through size and armaments. Signup and view all the answers

What best describes the rationale behind female choice in sexual selection?

Females select mates based on perceived fitness and phenotype. Signup and view all the answers

How does sexual selection generally differ between males and females?

Males focus on quantity, while females focus on quality in offspring. Signup and view all the answers

What is a typical result of intrasexual selection in the context of body size?

Males display greater sexual dimorphism, being larger than females. Signup and view all the answers

In a population practicing polyandry, what is likely to happen to the males?

Males usually acquire multiple mates. Signup and view all the answers

What is the primary difference between intrasexual and intersexual selection?

Intrasexual selection is focused on competition among the same sex, while intersexual is based on choice by the rare sex. Signup and view all the answers

Why do larger males often win in competitive scenarios for mating?

They can physically confront other males more effectively. Signup and view all the answers

What does the term 'sexual dimorphism' refer to in the context of sexual selection?

Marked differences in physical traits between sexes, such as size or weapons. Signup and view all the answers

What role does population size play in the mutation rate of a species?

Population size directly affects the number of meiotic events and mutations. Signup and view all the answers

What is a significant characteristic of dominant alleles?

They spread quickly when beneficial. Signup and view all the answers

What is the consequence of having a small population in terms of adaptation?

Adaptation is slower due to fewer available mutations. Signup and view all the answers

How does HIV management take advantage of the virus's mutation rate?

By applying triple therapy to lag its evolution. Signup and view all the answers

How do quantitative traits differ from simple genetic traits?

Quantitative traits are determined by variations in many loci. Signup and view all the answers

What effect does genetic heritability have on the response to natural selection?

Stronger heritability leads to stronger evolutionary responses. Signup and view all the answers

Which of the following best describes 'macromutation'?

A large DNA segment change, often beneficial. Signup and view all the answers

What happens to the mutation rate in humans as males age?

The mutation rate increases. Signup and view all the answers

What does genotype refer to in evolution?

The genetic basis that influences a phenotype. Signup and view all the answers

In the context of evolution, what is meant by 'quantitative traits'?

Traits determined by multiple genetic loci. Signup and view all the answers

What is the significance of the 'mutation rate' per base in humans?

It determines the number of mutations per generation. Signup and view all the answers

What does the term 'anti-evolution therapy' refer to in HIV treatment?

Reducing viral population sizes to limit mutations. Signup and view all the answers

How does genome duplication contribute to evolution in jawed fish?

It helps increase the variety and complexity of traits. Signup and view all the answers

What is an example of a trait that has a simple genetic basis?

Alcohol resistance in fruit flies. Signup and view all the answers

Study Notes

Microevolution to Speciation

Microevolution is about change within a species over a short time, impacting a species' gene pool.
Macroevolution focuses on the evolution of the type and number of species over a longer time.
Macroevolution explains how different species arise and why they differ, even with a common ancestor.

Problems with Darwin's Model

Darwin's model of natural selection assumed traits were blended in offspring, which reduces variation.
Blending inheritance destroys existing variations.
Darwin's assumptions worked better with the understanding of genetics.

Genetics Rescuing Darwin

Genetics shows that variation is maintained, not removed, by natural selection.
Variations that are heritable lead to more successful organisms, which in turn are better adapted.

Mutation and Heredity

Mutation is the source of new variation by changing DNA
Mutations provide novelty that selection can act on
Not all mutations have phenotypic effects; some are silent, some may cause a change in the protein, and some can halt the protein production.

Mendelian Genetics

Mendelian genetics show that variation is preserved through generations.
Mendel's theory works well with natural selection to show how traits form from genes, and how population size strongly promotes mutation

Evolution in the Era of Genetics: 1. Mutation

There are different types of mutation: silent, missense, nonsense.
Silent mutations don't affect protein function.
Missense mutations change amino acid sequences that lead to variations in phenotype.
Nonsense mutations stop production of proteins, dramatically impacting the organism.

Evolution in the Era of Genetics: 2. Mutation and Heredity

DNA is underpinned by genes
Genes express phenotype
Mutations in genetic codes influence phenotype

Other Mutational Events

Macromutations: Large-scale genetic changes affecting many genes
Gene duplication: Creates extra copies of genes, which may lead to novel genes
Endosymbiosis: Explains the evolution of mitochondria and chloroplasts in eukaryotes.
Change in karyotypes: Modification in chromosome numbers.
Polyploidy: Duplication of the entire genome.

Evolution and Mutations: Small or Large Effects?

Which types of mutations are crucial for evolution?
Normal mutations are small variations.
Big mutations cause negative physiological reactions and can thus be detrimental.
Natural selection is more effective on smaller-effect mutations.

Natural Selection and Genetic Variation

Natural selection can only make use of existing genetic variation.
Some species have high genetic variation, some have little, which influences how much change can happen

Evolution and Population Size

Population size is essential for evolution, because mutations happen in every generation.
Small populations, due to fewer opportunities for reproductions and mates, result in fewer opportunities for changes, which causes slower evolution.

The Influence of Population Size on Mutation and Adaptation

Every time meiosis happens, there are some mutations
The number of mutations rises with age in males
Large populations have more meiotic events and more chances for mutations
Small populations have fewer opportunities, meaning slower evolution
HIV is an example of how a small population size can lead to rapid evolution of resistance

Variation in Gene Expression

Genetic variation in gene expression affects phenotype
Gene expression impacts which proteins are produced, when they are produced, and where they're produced influencing phenotypes in development stages and in different tissues.

Impact of Dominance and Rate of Adaptation

Dominant alleles give phenotypes in heterozygotes, and can be selected for quickly even when rare.
Recessive alleles need both copies of a gene to be expressed. They take longer to be selected for.
Evolution is strongly biased toward dominant mutations, which are very common.

Quantitative/Complex Traits

Traits show variation in phenotypic characteristics.
Genotype determines the expression of traits.
Traits are influenced by the sum of many genetic loci interactions.
Heritability of traits can differ across generations because environments are dynamic

Modeling Selection on Mendelian Loci

Understanding the interplay between genetics, natural selection, and the environment to predict and understand evolution
Traits are usually controlled by multiple genes in most cases and these interact in complex ways

Understanding Genetic Diversity

Natural selection should drive good traits, but the amount of genetic diversity in a population is also important, if the bad traits show a higher frequency.
Every organism has genetic diversity.
Genetic diversity is abundant.

Different Types of Genetic Variation

Deleterious - variations are bad, reduce fitness
Neutral - no effect on fitness
Advantageous - variations help survival or reproduction

Why Do Genetic Diseases Persist?

Many genetic diseases are recessive, this means that an individual has to have 2 copies of the harmful version to show signs of the disease and only a small percentage of the population are homozygous for the harmful recessive gene

New Deleterious Mutations

Many new deleterious mutations occur in every meiosis, but selection swiftly removes them
They are usually recessive and selection in a large population is slow

Genetic Diversity and Bottlenecks

Population bottlenecks can occur due to events such as natural disasters or disease outbreaks
Bottlenecks lead to reduced genetic diversity, as individuals are lost
The remaining individuals pass on any existing genetic variation, which can cause higher representation of some traits and variations.

Neutral mutations not subject to selection

Neutral mutations do not affect phenotype.
These are usually outside of genic regions, like introns or third base pairs (no amino acid change).
Small populations have more pronounced effects of neutral mutations.
Large populations have a larger representation of neutral mutations over time.

Speed of Divergence when Separate

Rate of reproductive isolation differs between species.
Mammals have lower tolerance of hybridization than other groups, requiring faster reproductive isolation.

How Do Organisms Adapt to Changing Environments

The rate of speciation is variable.
Speciation rates depend on niche space and resources available in a new environment
Diversification occurs when new habitats have sufficient resources.
When niches become saturated, the rate of speciation slows.

The Paradigm

Spatial isolation creates independent gene pools (allopatric, peripatric).
Divergence is based on evolutionary processes, which can happen when groups are isolated from each other leading to speciation.

Spatially Divergent Selection with Gene Flow

Spatial isolation can promote speciation
Different phenotypes that live in similar environments can still be different due to different evolutionary pressures

Sky Islands

Mountain tops/peaks are isolated habitat, like little islands.
Species evolve in isolated areas due to limited dispersal (i.e. the top of a tall mountain).

Many Mammal Radiations Come After the Landscape

Geological events like the uplift of mountain ranges or the formation of new land masses may create new or modified habitats, thereby leading to new speciation.

General Summary of Speciation

Species are defined by their inability to interbreed and exchange genes with other species.
Speciation can be caused by factors like geographical isolation (allopatric speciation).
Speciation can also happen when there is a sudden environmental change where populations adapt to new environments (sympatric speciation)
Natural selection is the main driving force for change in evolution, but genetic drift is a major factor in small populations.

Sexual Dimorphism

Sexual dimorphism is the distinct differences in physical characteristics between males and females within a species.
These differences in structure can lead to male-male competition.
Females will pick a mate who meets their criteria for the best traits for progeny.
The choice can be arbitrary.

Intrasexual vs Interssexual Selection

Intrasexual selection: Competition between males within a species for access to females
Interssexual selection: Females choosing males based on their traits
These are strategies in the pursuit of reproduction
Sexual selection leads to male-male competition and mate choice

Sexual Conflict

Males and females may have conflicting interests in reproduction
This gives way to sexual conflict– male and female strategies can differ dramatically, in some cases greatly impacting the health of the female.

Summary of Sexual Selection

Natural Selection leads to the survival and reproduction of organisms with characteristics that are most successful in a given environment.
Sexual Selection is part of this process involving competition within the same sex (intrasexual) and/or choice by the opposite sex (intersexual).
The traits produced by these types of selection can have significant costs or benefits to the individual.

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Description

Test your knowledge on mutations, natural selection, and reproductive isolation in organisms. This quiz explores the differences between microbes and larger organisms, the mechanisms of genetic isolation, and the implications of sexual selection in evolution. Dive into the world of genetics and see how well you understand these concepts!