Biology

Genetics and Evolutionary Biology

1,123 Questions

Genetics and evolutionary biology explain how traits are passed from parents to offspring and how species change over time. Key concepts include genetic drift, inbreeding, and heredity. This topic is fundamental for the biology section of many competitive tests.

Heredity and traitsGenetic variations and driftInbreeding conceptsEvolutionary mechanisms

Genetics and Evolutionary Biology Questions

Multiple choice

Which of the following statements is CORRECT about genetic drift?

  1. It has its greatest impact on gene pool frequencies in bigger populations.

  2. It takes place independently of mutation and recombination.

  3. It occurs due to mutation.

  4. It occurs due to natural selection.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Genetic drift operates independently of mutation, recombination and other evolutionary mechanisms, i.e. genetic drift can occur in a population whether or not other evolutionary processes are operating.

Multiple choice

Rapid random changes in gene pool frequencies taking place in a small population are the consequence of

  1. genetic drift

  2. founder effect

  3. bottleneck effect

  4. natural selection
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The significant changes in gene frequencies in small, reproductively isolated populations can occur by chance. They are totally independent of mutation, recombination and natural selection. The smaller the population, the more susceptible it is to such evolution.

Multiple choice

Which of the following statements is CORRECT regarding genetic bottlenecks?

  1. They take place when there are severe environmental changes that alter natural selection so that most members of a species die before reproducing.

  2. The result is typically increased genetic diversity in a population following a genetic bottleneck.

  3. They minimze the fertility of the survivors.

  4. They does not affect genetic diversity in a population.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The result of such catastrophes is a dramatic reduction in genetic diversity of future generations. The variability is lost at the time of the bottleneck as a result of most individuals dying without reproducing.

Multiple choice

In which of the following societies would genetic drift have the least probability of causing rapid evolution?

  1. A fleet of 12-16 isolated humans living 70,000 years ago in Southern Africa.

  2. Modern day Japan

  3. A flock of 40 members of a religious sect who had nothing to do with their neighbours in ancient Rome for 8 generations.

  4. Ancient Japan
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Japan has a population of over 125 million people who form one large potentially interbreeding society. Society was divided into two classes in Feudal Japan, the nobility and the peasants. The noble class made up roughly 12% of the population with peasants making up the rest. In such a population, genetic drift would have virtually no effect.

Multiple choice

How can we justify the fact that, contrary to Gloger's Rule, millions of dark complexioned people live in temperate and even Arctic latitudes today?

  1. When a group of light skin people migrates into far northern regions, natural selection makes their skin dark only in few generations.

  2. Gloger's Rule is a hypothesis.

  3. Human population have been very active in moving around the globe in recent years.

  4. When a group of light skin people migrates into far northern regions, natural selection makes their skin dark in many generations.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Today the rate of evolutionary change for skin colour is much slower than the homogenizing effect of human migration. This process of interregional movement of societies has been accelerating, particularly since the time of Columbus.

Multiple choice

An individual's personal physical characteristics are the results of

  1. genetic inheritance

  2. environmental factors shaping the human bodies as they grow from childhood to adulthood

  3. genetic inheritance with some shaping by environmental forces also

  4. random chance or luck
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

We are mostly the product of the combination of genes that we inherited from our parents. However, environmental influences also have an effect. For example, severely undernourished children are not likely to reach their full potential stature.

Multiple choice

Gloger's Rule states that

  1. There should be a random distribution around the world of people having very little concentration of skin pigmentation.

  2. Dark skin provide benefit for individuals residing in far northern latitudes.

  3. In series of generations, natural selection is mainly responsible for variation in skin complexion.

  4. There is a uniform distribution around the world of people on the basis of skin pigmentation.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

There is a selective advantage for people with dark complexion in regions of intense solar radiation. Similarly, light complexion is an advantage in areas with significantly less sunlight. This is due to the fact that melanin is a protective shield.

Multiple choice

The increasing frequency of yellow-brown hair among Australian, primitives as one moves inland from the southwest coast of Australia is a prominent example of

  1. random variation

  2. progressive gradation

  3. discontinuous distribution

  4. continous variation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The gradual, more or less continuous change in hair colour from one group of primitives to another is not random or haphazard. There probably is a progressive gradation because there are different evolutionary pressures from one region to another.

Multiple choice

The isolated pockets of red-haired people in New Zealand is an example of discontinuous distribution. This distribution pattern is most likely the result of

  1. expatriation of red-haired people

  2. natural selection assisting, red hair

  3. random mating

  4. genetic drift
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This distribution pattern is most likely the result of migrations of group of red-haired people into areas where other hair colours predominated. However, it could also result from discriminatory marriage partner selection.

Multiple choice

Genetic diversity is related to

  1. gene based diversity

  2. types of communities in an area

  3. diversity and evolution of species with a genus

  4. types of species within a community

  5. -
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct Answer: gene based diversity

Multiple choice

Which of the following best expresses the main idea of the passage?

Directions: Read the passage and answer the question.

In nearly all human populations a majority of individuals can taste the artificially synthesized chemical phenylthiocarbonide (PTC). However, the percentage varies dramatically – from as low as 60% in India to as high as 95% in Africa. That this polymorphism is observed in non - human primates as well indicates a long evolutionary history which although obviously not acting on PTC, might reflect evolutionary selection for taste discrimination of other, more significant bitter substances, such as certain toxic plants. A somewhat more puzzling human polymorphism is the genetic variability in earwax, or cerumen which is observed in two varieties. Among European populations 90% of individuals have a sticky yellow variety rather than a dry, gray one, whereas in northern China these numbers are approximately the reverse. Perhaps like PTC variability, cerumen is an incidental expression of something more adaptively significant. Indeed, the observed relationship between cerumen and odorous bodily secretions denote that during the course of human evolution, genes affecting body secretions, including cerumen, came under selective influence.

  1. Some human polymorphisms might be explained as vestigial of evolutionary adaptations that still serve vital purposes in other primates.

  2. Sensitivity to taste and to odors have been subject to far greater natural selection during the evolution of primates than previously thought.

  3. Polymorphism among human populations varies considerably from region to region throughout the world.

  4. The human senses of taste and smell have evolved considerably over the course of evolutionary history.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the first paragraph the author’s main concern is to point out that the variability among human populations regarding sensitivity to PTC might be a trace of the evolutionary process of natural selectivity. Then in the second paragraph the author offers a similar suggestion about variability in earwax type. To support these assertions the author refers that both characteristics still serve useful purposes among non-primates from whom humans presumably evolved. This inference is especially clear with respect to indentifying bitter substances that might be toxic. (a) accurately reflects the author’s main assertion and supporting evidence.

Multiple choice

It can be inferred from the passage that human populations vary considerably in their

Directions: Read the passage and answer the question.

In nearly all human populations a majority of individuals can taste the artificially synthesized chemical phenylthiocarbonide (PTC). However, the percentage varies dramatically – from as low as 60% in India to as high as 95% in Africa. That this polymorphism is observed in non - human primates as well indicates a long evolutionary history which although obviously not acting on PTC, might reflect evolutionary selection for taste discrimination of other, more significant bitter substances, such as certain toxic plants. A somewhat more puzzling human polymorphism is the genetic variability in earwax, or cerumen which is observed in two varieties. Among European populations 90% of individuals have a sticky yellow variety rather than a dry, gray one, whereas in northern China these numbers are approximately the reverse. Perhaps like PTC variability, cerumen is an incidental expression of something more adaptively significant. Indeed, the observed relationship between cerumen and odorous bodily secretions denote that during the course of human evolution, genes affecting body secretions, including cerumen, came under selective influence.

  1. sensitivity to certain bodily odours

  2. capacity for hearing

  3. vulnerability to certain toxins found in plants

  4. ability to discern bitterness in taste
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the first paragraph of the passage, the author points out that the ability to taste PTC varies among human populations. Also, the final sentence of that paragraph refers to “other, more significant, bitter substances…” it can reasonably be inferred from these two statements, considered together, that PTC is a bitter substance.

Multiple choice

Which of the following statements is true?

  1. Mutation is more common in recessive condition.

  2. Mutation is more common in dominant condition.

  3. Mutation is constant in a population.

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. It is more common in dominant condition as it is expressed here.