Question 1

Scientists theorize that life began to form more than _____ years ago:

Accepted Answer

The most widely accepted theory for the origin of life suggests that it occurred around 3.5 billion years ago, during a time when the Earth's atmosphere was rich in methane, ammonia, and hydrogen. These gases, along with lightning strikes and volcanic activity, are thought to have created the necessary conditions for organic molecules to form and eventually evolve into primitive living organisms. Therefore, option B is the best choice.

Question 2

A selective agent places __________on certain individuals in the population.

Accepted Answer

Selective agents exert selective pressure on certain individuals in a population. Selective pressure can be the result of various factors, such as environmental conditions, availability of resources, or interactions with other individuals in the population. The individuals that are better adapted to the selective pressure are more likely to survive and reproduce, passing on their advantageous traits to their offspring. Over time, this can lead to evolutionary changes in the population.

Question 3

Selective agents act on the ______ of members of the population.

Accepted Answer

Selective agents act on the observable traits of individuals, which are their phenotype. It is the phenotype that interacts with the environment and determines an individual's fitness or ability to survive and reproduce. Therefore, selective agents can only act on the phenotype, not the genotype, which is the genetic makeup of an individual that determines its phenotype.

Question 4

Any factor which brings about differential fertility is called a:

Accepted Answer

A selective agent is a factor that causes some individuals in a population to have higher reproductive success than others, leading to differential fertility. Selective pressure refers to the effect of the selective agent on the population, but it does not necessarily involve fertility specifically. Mutation agents and mutation rates are both related to genetic variation, but they do not directly cause differential fertility.

Question 5

Microevolution refers to:

Accepted Answer

Microevolution refers to changes in the frequency of alleles in a population over time, which can occur for various reasons such as genetic drift, gene flow, and natural selection. It does not necessarily involve the formation of new species, so option D is incorrect. Option B is incorrect because microevolution can occur due to other factors besides natural selection, such as genetic drift. Option C is incorrect because mutations are only one source of genetic variation, and not all changes in allele frequencies necessarily involve mutations.

Question 6

The specific place where a particular animal lives is that animal's:

Accepted Answer

Habitat refers to the specific place where an animal lives and includes factors such as climate, food sources, and shelter. Environment refers to the broader surroundings of an organism and includes physical, chemical, and biological factors. Ecological niche refers to the role an organism plays in its habitat, including its interactions with other organisms and its use of resources. Therefore, habitat is the best choice for describing the specific place where a particular animal lives.

Question 7

The specific term used for the elements of the environment that are products of human behavior is the:

Accepted Answer

The cultural environment consists of the elements of the environment that are products of human behavior, such as customs, beliefs, values, and artifacts. Ecological niche refers to the role and relationships of a species within its ecosystem. Physical environment refers to the natural elements of the environment such as climate, terrain, and resources. Habitat refers to the specific geographical area where a particular organism lives.

Question 8

The deliberate breeding of domesticated plants or animals is called:

Accepted Answer

The deliberate breeding of domesticated plants or animals is called artificial selection. In this process, humans select and breed individuals with desirable traits to create offspring with those traits. This is different from natural selection which occurs without human intervention. Breeding selection and sexual selection can be more general terms and may not always refer specifically to deliberate human breeding.

Question 9

Fitness refers to:

Accepted Answer

Fitness refers to how well an individual or population is adapted to the requirements imposed by the environment.

Question 10

An example of a selective agent in humans would be:

Accepted Answer

A selective agent is any factor or condition that can affect the survival or reproduction of a population. Smallpox has been a major selective agent in human history, killing a significant number of individuals and increasing the fitness of those who were immune. Earthquakes and floods may cause damage and loss of life, but they do not directly affect the genetic makeup of a population, making them less relevant as selective agents in this context.

Question 11

Fitness is:

Accepted Answer

Fitness is defined as the degree to which an organism is adapted to its environment and able to survive and reproduce. It is not solely based on physical strength or good health, but rather how well an organism can meet the demands of its environment. Option B is not completely accurate as fitness is not solely based on physical strength compared to others of its species. Option C is not completely accurate as an organism can have good health but still not be well adapted to its environment.

Question 12

The presence of several distinct forms within a population-such as A,B,O,and AB blood types-is termed:

Accepted Answer

Polymorphism refers to the presence of multiple forms or variations within a population, such as different blood types. Pleiotropy refers to a single gene influencing multiple traits, and polytypy is not a commonly used scientific term.

Question 13

Each species occupies a _______ that is defined in terms of space and how that space is used by the organism.

Accepted Answer

An ecological niche is the specific role and position that a species has in its environment, including how it interacts with biotic and abiotic factors. It encompasses the resources that a species uses, as well as how it contributes to ecosystem function. A habitat refers to the physical location where a species lives, but does not fully encompass its ecological role. Microenvironment and microhabitat refer to smaller-scale aspects of an organism's environment, such as a specific patch of soil or a crevice in a rock, and do not necessarily encompass the full range of resources and interactions that make up an ecological niche.

Question 14

An example of a possible selective agent would be a:

Accepted Answer

All of the above options could potentially act as selective agents. A disease organism could select for individuals with genetic immunity or resistance, a drug could select for individuals with a specific metabolic pathway that can break down the drug, and a carnivore could select for individuals with adaptations that make them more difficult to catch or kill.

Question 15

Fitness:

Accepted Answer

Fitness refers to an organism's ability to survive and reproduce in a specific environment. As environments change, so does the fitness of different individuals. Therefore, fitness varies with the situation. The other options are not true as fitness can sometimes be greater for heterozygous individuals (known as heterozygote advantage) and can vary among homozygous individuals depending on the specific traits being selected for.

Question 16

Darwin's finches are found in:

Accepted Answer

Darwin's finches are named after Charles Darwin and were first observed by him during his voyage to the Galápagos Islands.

Question 17

Fitness could best be measured by how:

Accepted Answer

Fitness in a biological context is often measured by an individual's reproductive success, i.e., the number of offspring an individual can produce and support to reproductive age.

Question 18

The term ecological niche refers to:

Accepted Answer

The ecological niche refers to both the microenvironment (habitat) and the way the organism interacts with that environment in terms of resource use and interactions with other organisms. Therefore, choices B and C (microenvironment and exploitation) are both correct, making option D the best choice. Option A is not correct as it refers to everything outside of the organism, which would include things that are not part of the organism's niche.

Question 19

Mosquitoes have been controlled in most parts of the world by the spraying of DDT.But after years of repeated sprayings,the number of mosquitoes has been increasing in spite of the continued use of DDT because:

Accepted Answer

DDT-resistant mosquitoes survived and reproduced, passing on their resistance to their offspring. Over time, a larger and larger portion of the mosquito population became resistant to DDT, making it less effective in controlling their numbers.

Question 20

The living elements which surround an organism,such as plant life,are the:

Accepted Answer

The biological environment refers to the living elements that surround an organism, such as plant and animal life. The physical environment refers to the non-living elements, such as climate and geology. The cultural environment is related to human society and its impact on the surroundings, and microenvironment refers to the immediate surroundings of an individual organism. Therefore, the best choice for the living elements surrounding an organism is the biological environment (B).

Quiz 5: Natural Selection and the Origin of Species