Question 1

True or false: A genealogical species definition includes fewer organisms than a biological species definition.

Accepted Answer

A genealogical species definition, which focuses on the genetic history and similarities among organisms, can be more restrictive and specific than a biological species definition, which primarily considers reproductive isolation. This can lead to the genealogical approach including fewer organisms within a species because it may split what is considered a single species under the biological definition into multiple species based on genetic differences.

Question 2

Genealogical species are groups that have diverged from a common ancestor but aren't yet reproductively ________.

Accepted Answer

The answer of Genealogical species are groups that have diverged...

Question 3

The eggs released by sponges during reproduction have proteins on their surfaces that prevent sperm from different sponge species from binding to the eggs. What type of reproductive isolation would include this example?

Accepted Answer

The proteins on the surface of sponge eggs represent a form of gamete incompatibility. This type of reproductive isolation prevents different species from successfully fertilizing each other, even if they manage to come into contact during reproductive events.

Question 4

-California tarweed seeds were able to reach the Hawaiian Islands, and a new species emerged from this isolated population. What concept applies to this example?

Accepted Answer

The founder effect describes how a new population starts by a small number of individuals, which can lead to significant genetic differences from the original population. In this case, the California tarweed seeds that reached the Hawaiian Islands represent a small, isolated population that gave rise to a new species, illustrating the founder effect.

Question 5

Which scenario best describes the terms "subspecies" and "race"?

Accepted Answer

"Subspecies" refers to populations of the same species that have distinct physical or genetic differences and can interbreed but are separate enough to be classified as different subspecies. "Race" is a term that has been historically used to describe human populations with physical differences, but it is now considered outdated and inappropriate. In the case of option B, the two populations of birds with different amounts of orange coloration could be considered different subspecies as they have some physical differences but can still produce viable offspring if they were not separated by a mountain range.

Question 6

What type of reproductive isolation would include closely related species of orchids that never mate in the wild because they bloom at different times?

Accepted Answer

The answer of What type of reproductive isolation would include...

Question 7

A gene exists as two alleles in a population of freely mating individuals. If 40% of the population carries the recessive allele (a) for the gene, what percentage of the population has the homozygous recessive aa genotype?

Accepted Answer

Assuming Hardy-Weinberg equilibrium, we can use the equation p + q = 1, where p is the frequency of the dominant allele and q is the frequency of the recessive allele. Since we know that 40% of the population carries the recessive allele, q = 0.4. Therefore, p = 0.6. 
To find the frequency of the homozygous recessive genotype (aa), we can use the equation q^2 = 0.4^2 = 0.16 or 16%.

Question 8

You read that two populations of hyena are different subspecies. How would these populations compare?

Accepted Answer

The ability to produce fertile offspring is one of the defining characteristics of two individuals or populations belonging to the same species. If two populations of hyenas are different subspecies, it means they are genetically distinct from each other but still capable of interbreeding and producing viable offspring. Therefore, option (A) is the correct answer. Option (B) is not necessarily true, as the size difference between populations does not determine subspecies classification. Option (C) and (D) are also not necessarily true, as behavioral and ecological differences may occur within subspecies as well as between them.

Question 9

About how long have modern humans existed?

Accepted Answer

Modern humans, also known as Homo sapiens, have existed for approximately 250,000 years according to the current scientific consensus. This means that Homo sapiens have been the only remaining species of human for a quarter of a million years.

Question 10

How are human fossils classified into species?

Accepted Answer

Human fossils are classified into species based on differences in their skeletal structure, including skull size and shape, bone thickness and shape, and dental structure. Comparisons are made to modern human skeletons as well as to the skeletal remains of other known extinct species. DNA analysis can also be used, but it is not always possible with ancient fossils that have degraded over time. Diet and skin color can provide additional information about the lifestyle and environment of the species, but they are not reliable indicators of classification.

Question 11

What is found when alleles among different human groups are analyzed?

Accepted Answer

When analyzing alleles among different human groups, it has been found that there are no race-specific alleles and no consistent patterns of allele frequencies within racial groups. This is because genetic variation is not distributed in discrete racial categories, but rather as a continuum. Therefore, it is not appropriate to assign genetic differences to specific races.

Question 12

Which example describes mechanical reproductive isolation?

Accepted Answer

Mechanical reproductive isolation refers to the physical or anatomical differences between species that prevent mating or fertilization. The example given in option B of two fly species having differently shaped genitals that prevent interspecies mating is the only one that fits this definition. The other options describe different types of reproductive isolation - geographical (option A), temporal (option C), and hybrid inviability (option D).

Question 13

You're studying two species of frog. How would you know if gradualism or punctuated equilibrium played a role in the formation of the two species from their common ancestor?

Accepted Answer

The degree of difference between two species is more influenced by the amount of time that has passed since they diverged from a common ancestor than by whether the speciation occurred gradually (gradualism) or in rapid bursts (punctuated equilibrium). Both mechanisms can lead to speciation, but the extent of differences observed between species is more directly related to the duration of evolutionary time since their divergence.

Question 14

True or false: Reproductive isolation is the only requirement for speciation.

Accepted Answer

While reproductive isolation is a key factor in speciation, it is not the only requirement. Other factors such as genetic divergence, ecological differences, and geographic barriers can also contribute to the formation of new species.

Question 15

Which question relates to population genetics and could be answered using the Hardy-Weinberg equation?

Accepted Answer

The Hardy-Weinberg equation predicts the genotype frequencies in a population under certain conditions, including no mutation, genetic drift, gene flow, natural selection, and random mating. Therefore, it can help answer the question about the frequency of a particular genotype in a future generation.

Question 16

True or false: Fossil evidence shows that all modern human populations evolved from human ancestors in Africa.

Accepted Answer

Fossil evidence and genetic studies support the theory that all modern human populations evolved from human ancestors in Africa, specifically in the region of East Africa. This theory is known as the Out of Africa hypothesis.

Question 17

Where can you find the most genetically diverse populations of humans?

Accepted Answer

Africa is considered to be the cradle of human evolution and the continent with the highest genetic diversity. This is due in part to a longer history of human presence and a larger population size compared to other regions. Additionally, Africa contains a wide range of geographical and ecological environments, which have contributed to the development of a diverse array of genetic adaptations among its populations.

Question 18

-What concept is illustrated by the figure above?

Accepted Answer

Punctualism, also known as punctuated equilibrium, is a concept in evolutionary biology that suggests species remain relatively stable for long periods, punctuated by short, rapid changes. This concept contrasts with gradualism, which proposes slow, steady change over time. The question mentions a figure (not visible here), but based on the options provided and the description, punctualism is the concept that involves rapid changes after periods of stability, fitting the scenario typically illustrated to contrast with gradual evolutionary changes.

Question 19

True or false: When a founder population has a small gene pool, evolutionary change is more likely to be rapid than if the founder population has a large gene pool.

Accepted Answer

When a founder population has a small gene pool, there is a higher chance of genetic drift and inbreeding, which can lead to rapid evolutionary change. In contrast, a larger gene pool may contain more genetic diversity and reduce the rate of evolutionary change.

Question 20

What results after a speciation event?

Accepted Answer

During a speciation event, one new species evolves from the original species, while the original species may either stay the same or evolve into something different. Therefore, choice C is the best answer. Option A is partially correct but doesn't consider the fate of the original species. Option B is not correct because only one new species evolves, and option D is not always correct since it's possible for the original species to continue to exist.

Quiz 12: Who Am I Species and Races