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The meaning of "The Sixth Mass Extinction" is __________.

the prediction that a sixth mass extinction of life on Earth will occur

Under the biological species concept, what criterion is used to assign populations of organisms to the same biological species?

being able to interbreed and produce fertile offspring

In some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called ligers. Male ligers are sterile but some female ligers are fertile. In the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. Furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences.

Applying the biological species concept, the production of ligers reveals that ______.

tigers and lions are separate species

The observation that led scientists to hypothesize that a meteor caused the mass extinction of dinosaurs 65 million years was __________.

finding iridium in rocks deposited about that time

Which of the following is a binomial?
Nitzschia jouseae

Nitzschia jouseae

favors intermediate phenotypes, selecting against phenotypes at both ends of a range and reducing variation

stabilizing selection

favors phenotypes at both ends of a range over intermediate phenotypes. This type of selection may occur when the habitat is varied

Disruptive selection

in sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. This often results in ________, differences between the sexes in size, appearance, and behavior

sexual dimorphism

__________ is a type of sexual selection in which individuals of one sex (usually males) compete directly for mates. This may involve ritualized displays or physical combat.

intrasexual selection

in a type of sexual selection often called ________, individuals of one sex (usually females) are choosy in selecting their mates. This choice is often based on the showy appearance of behavior of the male.

mate choice

Generation-to-generation change in the allele frequencies in a population is _____.


a particular version of a gene


A population is

members of the same species occupying the same area at the same time

How many alleles do you inherit for each genetic trait?


Allelic frequencies change in:

a population

A population bottleneck is often the result of a ___________


Which of the following events could NOT be caused by a population bottleneck?
Changes in allele frequency
Loss of alleles
Increased population size
Reduction in genetic variabilit

increased population size

The evolution of populations due to chance is

genetic drift.

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,

the frequency of the green allele will increase.

In a population with brown and green alleles for color, genetic drift

has more effect on the evolution of a small population.

Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?

Gene flow causes the frequency of the brown allele to increase.

Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection?
Green beetles migrate out of the population.
Green beetles leave more offspring than brown beetles because they are better at finding food.
A storm kills more green beetles than brown beetles by chance.
Green beetles and brown beetles always leave the same number of offspring.
Green beetles migrate out of the population, and brown beetles migrate into the population.

Green beetles leave more offspring than brown beetles because they are better at finding food.

What does it mean to say that pigweed is resistant to herbicide?

Pigweed plants thrive despite the application of herbicides intended to kill them.

In the past, herbicides were very effective as a pigweed killer, but today _____.

pigweed is taking over fields of cotton and soybeans

The scientists who produced the herbicide warned against overuse, saying that over time, ____.

resistant weeds would increase in number

Why is pigweed so difficult to control? Select all that apply.
the number of seeds it produces
the number of inches it grows daily
its thick, woody stem
the way it spreads like a vine on the ground and is hidden from view

the number of seeds it produces, the number of inches it grows daily; its thick, woody stem

What effect(s) has the proliferation of herbicide-resistant pigweed had on southern farmers? Select all that apply.
Their large machinery is prone to damage from the pigweed plants.
They have to hire laborers to cut and remove the weeds by hand.
They can't plant cotton or soybeans anymore.
They may have to pick their crops by hand.

their large machinery is prone to damage from the pigweed plants, They have to hire laborers to cut and remove the weeds by hand, They may have to pick their crops by hand.

What is an antibiotic?

It is a drug that can kill infectious bacteria.

About half of the antibiotics produced today _____.

end up in animal feed

How do bacteria populations become drug resistant?

Antibiotics remove drug-susceptible individuals but leave those that are drug resistant.
Bacterial populations are influenced ny natural selection
Some individuals are genetically resistant to antibiotics.

Which of these diseases cannot be treated with antibiotics?
the common cold
bacterial pneumonia
bacterial meningitis

the common cold

Penicillin was the first antibiotic used to fight disease. Why is it not widely used now?

Most strains of pathogenic bacteria are resistant to it now.

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