Test 1 Homework Q's

Which statement best describes how homologous structures evolve?

A basic structure inherited from a common ancestor may evolve different variations in different species.

Which scenario describes an example of genetic drift?

A drought killed many of the orchids living on a small island. By chance, only the pink and purple varieties survive, whereas the white‑flower variety is lost completely.

Microbes are in the domain _________ and __________ are prokaryotic.

Bacteria; Archaea

Place the taxonomic ranks in the correct order from the most general rank to the most specific rank.

Dear King Phillip Came Over For Good Soup (Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species)

Select the scenario that describes a mass extinction.

During the Cretaceous period 65 million years ago, an asteroid struck the Earth and killed nearly 80% of the species living on Earth, including the dinosaurs.

How do scientists use fossils to draw conclusions about the evolution of life on Earth?

Fossils can be dated, providing a timeline for when certain types of life existed on Earth.

How does hybridization among different species occur?

Individuals from two closely related species produce offspring that may or may not be able to produce offspring themselves.

Natural selection is the primary process responsible for adaptive evolution. Which phrase describes natural selection?

Individuals with adaptive inherited traits are more likely to survive and produce offspring.

What does having higher fitness mean in an evolutionary sense?

Individuals with genotypes favorable for current conditions are more likely to survive and reproduce.

Which of the statements describes the function of a prokaryotic plasmid?

It transfers prokaryotic genes during conjugation.

Use the natural selection interactive to answer the question. Suppose that the predator (the bird) saw no difference between the colors gray and light brown. What would the most likely effect be on the light brown background trial?

Light brown and gray subpopulations would rise more than the dark brown subpopulation.

Which scenario describes an example of founder effect?

Members of a brown‑winged finch species from the mainland fly to an island that is otherwise uninhabited by finches. They establish a new population with different allele frequencies than the original population.

Use the Natural Selection interactive to answer the question. Which statement provides the best summary of how natural selection affects individual beetles and the beetle population in the interactive?

Natural selection changed the shell color frequencies in the population over time, but did not change individual beetles' shell colors.

Which of the scenarios would most likely lead to allopatric speciation?

Over thousands of years, a mountain range gradually rises to a point where it is too high for cottontail deer on each side to cross over to the other side.

How do analogous structures arise in different species?

Similar structures develop independently in distantly related species that experience similar problems in their habitats.

The forearms of a human, a horse, and a bat are shown in the diagram. How do these structures provide evidence for common ancestry?

The mammals share a common ancestor. The same ancestral bone structure has evolved to produce different forearm functions.

Two hypothetical populations of rabbits live on a mountain, one at low elevation and the other at high elevation. Rabbits at the low elevation experience a mild climate and have short fur, whereas rabbits at the high elevation are exposed to cold conditions and have long fur. There are no geographic barriers separating the ranges of the two populations. An ecologist finds that in both the low and high elevation populations, there are a few rabbits that have intermediate fur length. She notes that the rabbits with intermediate fur length can successfully mate and produce offspring with rabbits that have short or long fur. What is the most likely explanation for why some rabbits have intermediate fur length?

There is gene flow between the low and high elevation populations.

How are archaea and bacteria alike?

They both lack a distinct cell nucleus and nuclear membrane.

What happens in convergent evolution?

Two distantly related species independently develop similar traits.

Compared to other pathogens, why do viruses have the highest relative risk to humans?

Virus genomes have a high mutation rate.

What is the Gram stain and what information does it provide about cells?

a cell-staining technique used to categorize bacteria by the presence or absence of a cell wall made up of a thick outer peptidoglycan layer

Which phrase best describes evolution?

a change in the frequency of alleles in a population over time

Which statement describes a monophyletic group?

a group of organisms that includes a single common ancestor and all of its descendants

A vestigial structure is

a previously beneficial structure that no longer serves an adaptive purpose

The Northern spotted owl and Mexican spotted owl arose from geographically isolated populations of the same ancestral owl species. The geographic ranges of the Northern spotted owl and the Mexican spotted owl are shown in the image. The evolution of the Northern spotted owl and Mexican spotted owl is an example of which type of speciation?

allopatric speciation

Select the definition of adaptation from the phrases provided.

an inherited trait that increases the survival and reproduction of organisms that bear it

Use the Natural Selection interactive to answer the question. For natural selection to occur, organisms with inherited traits that increase fitness have better reproductive success than organisms that do not have the more favorable trait. Which trait is used in the simulation as the example of a heritable variation within a trait?

beetle color

There are several methods by which genetic material can be exchanged between bacteria. Which of the terms describes direct cell‑to‑cell DNA transfer between bacterial cells?

conjugation

What are protists?

eukaryotes that can not be classified as either animal, plant, or fungi

The complete collection of genes and their variants within a population is called the population's

gene pool.

Imagine a population of beetles. Some gray beetles move into and start mating with a population of white beetles. This increases the frequency of genes for gray coloration in the white beetles' population. Which evolutionary process does this scenario describe?

migration

Imagine a population of moths. White moths are easier for birds to see and eat. Black moths blend into their surroundings, so they are less visible to birds than white moths. As a result, black moths are more likely to survive and reproduce, enabling the gene for black coloration to be passed on to the next generation. This increases the frequency of genes for black coloration in the population. Which evolutionary process does this scenario describe?

natural selection

Which type of chromosome(s) describes the genomes of most prokaryotes?

one circular, double‑stranded DNA chromosome

According to the biological species concept, what is the definition of a species?

organisms that can interbreed in nature to produce healthy offspring

Which term describes the study of the distribution of genetic traits and the allelic changes that occur within a population?

population genetics

What is reproductive isolation?

prevention of gene flow between two populations due to physical or behavioral barriers

Bacteria and Archaea are the two domains whose members are:

prokaryotic

Complete the sentence. Homologous structures are

similar structures which share a common ancestry, despite their differences in function.

Identify the statement that best defines systematics.

studying evolutionary relationships between species

In Africa, Lake Victoria is home to many distinct species of cichlid fish that vary in color from blue to red. Cichlid fish species that live in shallow water are blue and prefer to mate with other blue fish, whereas cichlid fish species that live in deep water are red and prefer to mate with other red fish. All of the cichlid fish species evolved from a single ancestral species and live together in the same habitat. The cichlid fish in Lake Victoria are an example of which type of speciation?

sympatric speciation

What characteristic is common to all living organisms, but is not a characteristic of viruses?

the capability of performing biological processes autonomously

What is sympatric speciation?

the divergence of two species from a common ancestor while in the same geographical location

Identify the description of a capsid.

the protein shell that encases and protects the genome of a virus

There are several methods by which genetic material can be exchanged between bacteria. Which term describes genetic transfer between bacterial cells that is mediated by a virus?

transduction

There are several methods by which genetic material can be exchanged between bacteria. Which of the terms describes the uptake of DNA from the environment by the host cell?

transformation

What is allopatric speciation?

two species diverging from a common ancestor due to geographical isolation

Unlike other microbes, archaea are able to thrive in:

very extreme (with respect to temperature, salinity, pressure, etc.) environments.

Viruses rely on a host cell to carry out metabolic functions. What molecule does a virus insert into a host cell that enables the virus to redirect the host cell's enzymes and ribosomes?

viral nucleic acids