Evolutionary Biology Quiz

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Questions and Answers

What is the primary effect of directional selection on a population's traits?

It increases the frequency of intermediate traits.

It maintains stability in trait frequencies.

It shifts the trait distribution toward one extreme. (correct)

It promotes the extinction of all traits.

How does disruptive selection influence a population?

It favors individuals with average traits.

It promotes speciation by favoring extreme traits. (correct)

It favors only the most common traits.

It creates a spectrum of intermediate traits.

Which of the following best describes stabilizing selection?

It increases the number of individuals with average traits. (correct)

It shifts traits towards less prevalent features.

It eliminates all traits that do not contribute to survival.

It favors extreme variations of a trait.

Which scenario is an example of directional selection?

Moths in a polluted area becoming darker. Signup and view all the answers

In what situation would disruptive selection most likely occur?

When resources favor both extremes of a trait spectrum. Signup and view all the answers

Which statement accurately differentiates natural selection from artificial selection?

Natural selection occurs without human intervention, while artificial selection is intentional. Signup and view all the answers

What is a potential consequence of disruptive selection over time?

Speciation, leading to the emergence of new species. Signup and view all the answers

Which trait variation is most likely to be favored by stabilizing selection?

Average birth weight in mammals. Signup and view all the answers

What evidence is considered the strongest line of evidence for evolution?

Molecular biology Signup and view all the answers

Which of the following best explains the concept of biogeography?

The geographic distribution of species Signup and view all the answers

How does genetic evidence help in tracing evolutionary relationships?

Through molecular similarities in DNA sequences Signup and view all the answers

Which example illustrates direct observation of evolution?

The evolution of antibiotic resistance in bacteria Signup and view all the answers

What percentage of DNA do humans and chimpanzees share?

98-99% Signup and view all the answers

Which past event helps explain the distribution of similar species?

Continental drift Signup and view all the answers

What led to the evolution of peppered moths in industrial England?

Pollution affecting their habitat Signup and view all the answers

What primary method allows scientists to compare genomes across species?

DNA sequencing Signup and view all the answers

What is the primary process through which individuals with advantageous traits are more likely to survive and reproduce?

Natural Selection Signup and view all the answers

Which mechanism of evolution is characterized by random changes in allele frequencies, especially in small populations?

Genetic Drift Signup and view all the answers

How does gene flow affect genetic variation within populations?

It introduces new alleles into the population. Signup and view all the answers

Which of the following describes mutations in the context of evolution?

They are the ultimate source of genetic variation. Signup and view all the answers

What is a characteristic of non-random mating?

It favors mating between individuals with similar traits. Signup and view all the answers

Which mechanism of evolution involves the transfer of alleles when individuals from different populations interbreed?

Gene Flow Signup and view all the answers

What is the founder's effect?

A type of genetic drift that occurs when a small number of individuals establish a new population. Signup and view all the answers

Which statement accurately represents the relationship between evolution and randomness?

Random events, such as mutations and genetic drift, introduce unpredictability into evolution. Signup and view all the answers

What is the primary outcome of gene flow between populations?

It increases genetic diversity in the receiving population. Signup and view all the answers

What occurs during the founder's effect?

A small group separates from a larger population, forming a new colony. Signup and view all the answers

How does the founder's effect impact genetic variation?

It leads to reduced genetic variation in the new population. Signup and view all the answers

Which statement accurately differentiates gene flow from the founder's effect?

Gene flow mixes genetic materials, whereas the founder's effect creates a genetically limited population. Signup and view all the answers

What happens to certain traits in a population affected by the founder's effect?

Certain traits may become more or less common by chance. Signup and view all the answers

Which example best illustrates the concept of gene flow?

A small group of wolves moves to a different territory and breeds with local wolves. Signup and view all the answers

What is the effect of gene flow on the genetic differences between populations?

It tends to eliminate genetic differences. Signup and view all the answers

Which characteristic is true for populations formed by the founder's effect?

They usually exhibit high frequencies of particular traits carried by the founders. Signup and view all the answers

What is the primary outcome of divergent evolution?

Species become more dissimilar Signup and view all the answers

Which of the following is an example of divergent evolution?

Whales evolving from a common mammalian ancestor Signup and view all the answers

What do vestigial structures indicate about an organism?

The species has lost the original function of certain structures Signup and view all the answers

Which feature is NOT commonly found in vertebrate embryos?

Fur coats Signup and view all the answers

What is the main focus of studying embryology in evolutionary biology?

To establish evolutionary relationships Signup and view all the answers

What is convergent evolution primarily characterized by?

Unrelated species developing similar adaptations Signup and view all the answers

How does molecular biology contribute to the study of evolution?

By providing data on unrelated organisms Signup and view all the answers

Which of the following correctly describes the significance of diversified traits in evolved species?

They enhance adaptability to specific environments. Signup and view all the answers

What factors contribute to the incompleteness of the fossil record?

Quick burial after death and geological processes Signup and view all the answers

Which statement accurately describes relative dating of fossils?

It estimates the age based on the rock strata position. Signup and view all the answers

What does half-life refer to in the context of radioactive decay?

The duration needed for half of a radioactive sample to decay. Signup and view all the answers

Which of the following best describes transitional fossils?

Fossils with characteristics of both ancestral and descendant groups. Signup and view all the answers

Why might soft-bodied organisms be underrepresented in the fossil record?

They often decay or are destroyed before fossilization occurs. Signup and view all the answers

How does absolute dating differ from relative dating?

Absolute dating uses decay rates of isotopes for age determination. Signup and view all the answers

What role do geological processes play in the fossil record?

They can destroy or bury fossils, leading to gaps in the record. Signup and view all the answers

In which environments is fossilization most likely to occur?

Wet and low-lying areas. Signup and view all the answers

Study Notes

Evolution: History and Mechanisms

Evolution is the process of change in species over time, arising from variations in traits that offer advantages for survival and reproduction in different environments
Darwin's book "On the Origin of Species" (1859) presented the theory of evolution by natural selection, where species change over time via differential survival and reproduction of advantageous traits
Darwin's theory was influenced by numerous discoveries and scientists: geologists (Hutton, Lyell) on the immense age of the Earth; artificial selection (Bakewell); population growth (Malthus); taxonomy (Linnaeus); anatomical studies (Owen); and embryology (von Baer)
Evolutionarily fit organisms have traits that enhance survival and reproduction, passing those traits to future generations. Fitness relates to an organism's capability to produce offspring who survive and reproduce.

Natural Selection

Variation: traits within populations vary, inheritable
Overproduction: more offspring are created than can be supported by available resources
Competition: limited resources cause competition for survival
Differential reproduction: organisms with advantageous traits survive and reproduce more successfully
Adaptation: traits favorable for survival and reproduction become more common, leading to adaptations to the environment

Types of Natural Selection

Directional Selection: favors one extreme trait value (e.g. larger beak size)
Disruptive Selection: favors both extreme trait values, selecting against the middle (e.g. small and large beak sizes)
Stabilizing Selection: favors average traits. reduces extremes (e.g., average birth weight in humans)

Artificial Selection

Humans intentionally select organisms with desirable traits for breeding, leading to rapid changes over generations
Example: Dog breeding, crop improvement

Sexual Selection

Natural selection where traits improve an individual's mate attraction are favored. Success in mating is emphasized
Traits are not always beneficial for survival

Mechanisms of Evolution

Natural Selection: individuals with advantageous traits survive and reproduce more, passing these traits
Genetic Drift: random changes in allele frequencies, impacting small populations more
Gene Flow (Migration): introducing new alleles into a population through mating with another population
Mutation: random changes in DNA sequence, creating new alleles
Nonrandom Mating: preference for specific traits in mate choice

Evidence for Evolution

Fossil Evidence: shows how species have changed over time
Comparative Anatomy: studies similarities and differences in body structures (homologous/analogous structures)
Embryology: similar developmental stages suggest common ancestry
Molecular Biology (genetics): DNA sequences show evolutionary relationships
Biogeography: species distribution reflects evolutionary history and adaptation to different environments
Direct Observation: observing evolutionary processes in organisms (e.g., antibiotic resistance)

Fossil Record

Incomplete due to fossilization rarity, destruction by geological processes, bias in fossil preservation
Relative dating: arranges fossils based on rock layer position
Absolute dating: determines the actual age of fossil via radiometric dating (measuring radioactive isotopes)

Transitional Fossils

Show intermediate characteristics between different groups, demonstrating evolutionary change
Archaeopteryx, Tiktaalik

Index Fossils

Fossils with wide geographic distribution, used to date rock layers and establish relative ages
Trilobites, Ammonites

Biogeography

Study of species distribution and how it relates to environmental factors, evolutionary history, and continental drift
Patterns of species distribution suggest evolutionary relationships

Comparative Anatomy

Studies similarities and differences in body structures
Homologous structures: similarities in structures due to shared ancestry, different functions (limbs of vertebrates)
Analogous structures: similar functions but different evolutionary origins (wings of birds and insects)

Macroevolution vs Microevolution

Macroevolution = large-scale evolutionary changes, leading to new species and higher taxonomic groups
Microevolution = small-scale changes within populations (e.g., changes in allele frequencies)

Vestigial Structures

Body parts with reduced function but remnants from ancestral species (e.g., human appendix)

Homeotic/Housekeeping Genes

Homeotic genes control body development
Housekeeping genes control basic metabolic functions, shared by different species, supporting common ancestry

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Description

Test your knowledge on the principles of natural selection, including directional, disruptive, and stabilizing selection. This quiz covers key concepts, evidence for evolution, and specific examples such as the evolution of the peppered moths. Challenge yourself with scenarios and learn more about biogeography and genetic relationships.