Q: Which of the following is a molecular trait commonly used in species identification?

The sequence of nucleotides in a specific gene, such as $\text{COI}$ in mitochondrial DNA

Q: Which scenario best demonstrates the use of molecular traits in species identification?

Comparing the DNA sequence of the $\text{cytochrome c}$ gene between two populations to determine if they are the same species.

Question 1

Which of the following best describes macroevolution?

Accepted Answer

The large-scale evolutionary changes that occur above the species level, such as the origin of new taxonomic groups and mass extinctions.

Question 2

Current estimates suggest that approximately how many species have been identified on Earth, and what is the estimated total number of species?

Accepted Answer

About 1.8 million identified; estimated total is 8.7 million.

Question 3

Which of the following is NOT a primary method used by biologists to identify a species?

Accepted Answer

Geographical location alone

Question 4

According to the biological species concept as proposed by Ernst Mayr, which of the following best defines a species?

Accepted Answer

A group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.

Question 5

Why is reproductive isolation important in the process of speciation?

Accepted Answer

It prevents gene flow between populations, allowing them to diverge genetically and form new species.

Question 6

Which of the following is a molecular trait commonly used in species identification?

Accepted Answer

The sequence of nucleotides in a specific gene, such as $	ext{COI}$ in mitochondrial DNA

Question 7

Which of the following is an example of a prezygotic isolating mechanism?

Accepted Answer

Temporal isolation, where two species breed at different times of the year

Question 8

Ecological isolation can be best illustrated by which of the following scenarios?

Accepted Answer

Two closely related frog species live in the same region but breed in different types of water bodies, such as one in fast-moving streams and the other in still ponds.

Question 9

Mechanical isolation prevents interbreeding between species by:

Accepted Answer

Preventing fertilization due to incompatible reproductive structures.

Question 10

Which of the following best distinguishes postzygotic isolating mechanisms from prezygotic mechanisms?

Accepted Answer

Postzygotic mechanisms act after fertilization, often resulting in inviable or sterile offspring, while prezygotic mechanisms prevent fertilization from occurring.

Question 11

A population of insects is split by a new river, and over time, the two groups develop different mating rituals and cannot interbreed even if brought together. Which type of reproductive isolation is this an example of?

Accepted Answer

Behavioral isolation

Question 12

Which scenario best demonstrates the use of molecular traits in species identification?

Accepted Answer

Comparing the DNA sequence of the $	ext{cytochrome c}$ gene between two populations to determine if they are the same species.

Question 13

Which of the following is a real-world example of prezygotic isolation?

Accepted Answer

Two species of orchids release pollen at different times, preventing cross-pollination.

Question 14

A scientist is studying two populations of frogs that look identical but have different mating calls and do not interbreed in the wild. According to the biological species concept, are these populations considered the same species?

Accepted Answer

No, because they do not interbreed and produce viable, fertile offspring.

Question 15

Which of the following equations could be used to estimate the total number of species on Earth if the number of identified species and the percentage of known species are given?

Accepted Answer

$	ext{Total species} = \frac{	ext{Number of identified species}}{	ext{Percentage of known species}}$

Question 16

Which of the following is NOT a prezygotic isolating mechanism?

Accepted Answer

Hybrid sterility

Question 17

A botanist discovers two plant populations that can interbreed in the lab but never do so in the wild because one grows in sandy soil and the other in clay soil. What type of isolation is this?

Accepted Answer

Ecological isolation

Question 18

Which of the following best explains why hybrid sterility is considered a postzygotic isolating mechanism?

Accepted Answer

It occurs after fertilization, resulting in offspring that cannot reproduce.

Question 19

If two species of fish spawn in the same lake but at different depths, which type of reproductive isolation is most likely preventing them from interbreeding?

Accepted Answer

Ecological isolation

Question 20

A researcher finds that two populations of beetles have identical physical features but differ significantly in their mitochondrial DNA sequences. What is the most likely conclusion?

Accepted Answer

They are likely different species, as molecular traits indicate genetic divergence.

Study Guide: Macroevolution and Species Concepts (Chapter 24)

Study Guide - Practice Questions

Study Guide - Flashcards