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Quizzes > Science

Natural Selection Unit Test Practice

Quick, free natural selection practice quiz with instant results and answer feedback.

Editorial: Review CompletedCreated By: A D R FajriUpdated Aug 24, 2025
Difficulty: Moderate
Grade: Grade 10
Study OutcomesCheat Sheet
Colorful paper art promoting a trivia quiz on natural selection for high school biology students

This quiz helps you review natural selection for your Grade 10 unit test and see what to study next. Answer 20 quick questions on variation, adaptation, and the effect of natural selection with instant results. For more practice, try the hardy weinberg quiz and the chapter 1 biology quiz, or build exam skills with a biology clep practice test.

What is natural selection?
A mechanism that eliminates all genetic variation in a population.
A random change in allele frequencies without any environmental influence.
A process where organisms better adapted to their environment tend to survive and reproduce.
A process where all organisms evolve in exactly the same direction.
Natural selection is the process by which organisms with traits suited to their environment have higher survival and reproduction rates. This differential survival leads to evolutionary changes over time.
Which of the following is an example of an adaptation?
Acquired habits learned during an organism's lifetime.
Thick fur in polar bears.
Random variation in fur color among rabbits.
Changes in an individual's diet due to seasonal availability.
An adaptation is a trait that enhances an organism's ability to survive and reproduce in a specific environment. Thick fur in polar bears is a clear example, as it provides insulation against cold climates.
What does 'fitness' mean in the context of natural selection?
The ability of an organism to survive and reproduce.
The physical strength or athletic performance of an organism.
The age and size of an organism.
The speed at which an organism can adapt to its environment.
In evolutionary biology, fitness refers to an organism's ability to survive and produce viable offspring. It is less about physical strength and more about successful reproduction.
Which factor is not involved in natural selection?
Differential survival and reproduction.
Acquired traits that are not passed on genetically.
Heritability of traits.
Inherited variation.
Natural selection acts upon heritable genetic variations in a population. Acquired traits, which develop during an organism's lifetime and are not passed on genetically, do not influence natural selection.
What is the primary role of genetic variation in a population?
It only occurs in populations with low numbers.
It prevents any evolutionary changes from occurring.
It ensures all individuals remain identical over time.
It provides the raw material for evolution.
Genetic variation is crucial because it supplies the diversity of traits within a population upon which natural selection can act. Without variation, populations would not be capable of adapting to changing environments.
How does the environment influence which traits are advantageous?
It benefits only the largest or strongest organisms.
It has no impact on the traits present in a population.
It changes survival conditions, favoring traits that best suit the living conditions.
It causes all organisms to develop the same traits regardless of their needs.
The environment sets the stage by determining which traits confer survival advantages. Organisms that possess traits well-suited to the environmental conditions are more likely to survive and reproduce.
What does 'selective pressure' refer to?
A process that guarantees evolution will occur in a population.
A measure of an organism's physical strength.
An external factor that affects an organism's survival and reproductive success.
The internal mechanisms that generate random mutations.
Selective pressure includes any environmental or biological influences that affect an organism's chance of survival and reproduction. These pressures can drive evolutionary change by favoring advantageous traits.
How does mutation contribute to evolution?
By introducing new genetic variations into a population.
By eliminating all differences among individuals.
By ensuring that only beneficial traits are expressed.
By always resulting in harmful changes that reduce fitness.
Mutations are changes in DNA that can create new variations in a population. While not every mutation is beneficial, they provide the genetic diversity that natural selection can act upon.
Which statement best describes natural selection's effect on populations?
It leads to an increase in the frequency of advantageous traits.
It decreases the overall diversity within a population.
It eliminates all mutations from a population.
It causes all individuals to eventually have identical traits.
Natural selection favors traits that increase an individual's fitness, leading to a higher frequency of those traits in the population over time. This process results in populations better adapted to their environments.
Which of the following scenarios illustrates directional selection?
A population where the average beak size remains constant over many generations.
A population where beak sizes vary randomly without any noticeable trend.
A situation where beak sizes alternate between generations with no final shift.
A bird population where individuals with slightly longer beaks have increased access to food.
Directional selection occurs when one extreme of a trait offers a survival or reproductive advantage, causing the population's average to shift over time. In this case, longer beaks provide better access to food resources.
What is stabilizing selection?
A type of natural selection that favors intermediate variants and reduces extremes.
A selection process that results in a wide range of diverse traits.
A process that favors only the largest individuals in a population.
A pattern of evolution driven by random genetic drift.
Stabilizing selection favors individuals with average traits, thereby reducing variation by selecting against extreme phenotypes. This helps maintain a stable population trait and supports consistency in the population.
Which example best demonstrates disruptive selection?
A population where individuals with extremely small or extremely large beaks are favored over intermediates.
A population where the average beak size confers the highest fitness.
A situation where all beak sizes are equally advantageous.
A gradual shift in beak size where intermediate forms dominate.
Disruptive selection favors individuals at both extremes of a trait distribution rather than those with average traits. This mechanism can lead to the formation of two or more distinct phenotypes within the same population.
Which mechanism can decrease genetic variation in a population?
Mutation.
Gene flow.
Genetic drift.
Sexual reproduction.
Genetic drift involves random changes in allele frequencies and can lead to a reduction in genetic variation, particularly in small populations. Unlike mutation or gene flow, which introduce new genetic material, drift can reduce diversity by chance.
How does sexual selection differ from natural selection?
Sexual selection only acts on traits that help the organism hide from predators.
Sexual selection is a random process unrelated to survival.
Sexual selection specifically involves traits that enhance mating success.
Sexual selection always leads to larger body sizes in both sexes.
Sexual selection targets traits that improve an individual's chances of securing a mate and reproducing. While both natural and sexual selection influence evolutionary change, sexual selection is specifically tied to reproductive success.
What role does gene flow play in evolution?
It prevents changes in allele frequencies by stabilizing a population.
It causes immediate speciation by isolating populations permanently.
It eliminates mutations from a population.
It introduces new genetic material into a population by migration.
Gene flow is the transfer of genetic material between populations through migration. This process increases genetic diversity and can influence the course of evolution by introducing new alleles into a population.
How can natural selection lead to speciation?
By completely eliminating genetic variation in a population.
By causing immediate reproductive isolation through a single mutation.
By causing populations to diverge when different traits are selectively favored in distinct environments.
By ensuring that all populations maintain the same traits regardless of environmental differences.
Different environmental pressures can lead separate populations to favor different traits. Over time, this divergence in traits may result in reproductive isolation, ultimately leading to the formation of new species.
Which of the following represents a potential drawback of natural selection?
It may favor traits that are beneficial in the short term but become disadvantageous if the environment changes.
It guarantees that every offspring will be perfectly adapted to its surroundings.
It eliminates all genetic variation, leaving a population with no diversity.
It always improves the overall health and adaptability of a species.
Natural selection optimizes traits for prevailing conditions, but these traits might become disadvantages if the environment shifts rapidly. This short-term focus can be a drawback when adaptability is required in changing conditions.
In what way can human activities influence the process of natural selection?
By altering habitats, thereby changing selective pressures on populations.
By directly manipulating an organism's genetic code in natural environments.
By completely halting natural selection through technological intervention.
By ensuring all species evolve simultaneously in the same direction.
Human activities such as urbanization, pollution, and climate change can significantly alter natural habitats. These modifications shift the selective pressures on organisms, which can lead to rapid evolutionary changes in affected populations.
How do coevolutionary relationships demonstrate natural selection?
They typically reduce the fitness of both species involved in the interaction.
They show that species evolve completely independently, without affecting each other.
The reciprocal adaptations between interacting species highlight how each species drives evolutionary changes in the other.
They always result in one species gaining a permanent advantage over the other.
Coevolution involves two or more species influencing each other's evolution through reciprocal selective pressures. These interactions can result in traits that are advantageous for both, demonstrating the interconnected nature of evolutionary change.
Which scenario best illustrates the role of chance in evolution alongside natural selection?
All individuals have an equal chance of survival regardless of their traits.
Natural selection completely determines which alleles are passed on with no random influences.
The environment randomly changes an organism's traits without affecting survival.
A population undergoes a bottleneck event where random deaths drastically alter allele frequencies in addition to selective pressures.
This scenario shows that chance events, like a bottleneck, can significantly alter a population's genetic makeup. These random events work in tandem with natural selection, especially in small populations, to influence evolutionary outcomes.
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Study Outcomes

  1. Understand the fundamental principles of natural selection and evolution.
  2. Analyze how environmental factors influence phenotypic variations in populations.
  3. Apply the concept of adaptation to explain survival and reproductive advantages.
  4. Evaluate evidence supporting selective pressures in diverse ecosystems.
  5. Interpret the impact of genetic variation on evolutionary outcomes.

Natural Selection Unit Test Review Cheat Sheet

  1. Natural Selection Basics - Think of nature as the ultimate boss battle: survivors with the best moves win big, reproduce, and pass on their killer strategies. This process is the heart of evolutionary biology and explains why giraffes have necks and cheetahs have speed.
  2. Darwin's Four Postulates - Darwin broke evolution down into four epic rules: variation exists in every population, traits are passed down, more offspring are born than can survive, and survival isn't random. Together, they form the game plan for how natural selection reshapes life over generations.
  3. Adaptations - Adaptations are like nature's custom outfits, tailored to help organisms rock their environments - like giraffes' long necks for high-leaf feasts. These traits boost survival and are passed along, making each generation suit up even better.
  4. Types of Natural Selection - There are three epic modes: directional (pushing traits one way), stabilizing (keeping it middle-ground), and disruptive (extremes on both ends). Each mode sculpts populations differently, like a sculptor chiseling marble into unique shapes.
  5. Survival of the Fittest - "Fittest" isn't about gym reps but about who leaves the most offspring. It's all about genetic success and making sure your DNA party keeps going generation after generation.
  6. Common Misconceptions - Evolution doesn't happen because individuals level up; it's a population-wide saga that unfolds over generations. Free yourself from myths like "people will evolve big muscles from exercise," and get the real scoop.
  7. Evidence of Natural Selection - Remember the peppered moth drama during the Industrial Revolution? Dark-colored moths thrived on soot-covered trees, showing natural selection in action. Real-world examples like this turn the theory into tangible reality.
  8. Role of Mutations - Mutations are the plot twists in DNA, introducing new variations that natural selection can choose from. While many are neutral or harmful, the lucky ones can drive cool adaptations like antibiotic resistance in bacteria.
  9. Sexual Selection - Some traits are flashy showoffs meant to woo mates - think peacock tails or elk antlers - sometimes even at the cost of survival. This form of selection highlights that love (and choosing a partner) can shape evolution, too.
  10. Artificial Selection - Humans have been the ultimate breeders, shaping dogs, crops, and livestock to our liking by picking the winners each generation. This backyard version of natural selection proves how powerful selective pressure can be.
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