Benchmark 2 evolution

Mutation

A change in a gene or chromosome.

Trait

A characteristic that an organism can pass on to its offspring through its genes.

Population

A group of individuals that belong to the same species and live in the same area

Species

A group of similar organisms that can breed and produce fertile offspring.

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Fitness

Ability of an organism to survive and reproduce in its environment

Evolution

Change in a kind of organism over time; process by which modern organisms have descended from ancient organisms.

Which lines of evidence did Darwin use to explain the variety of finches on the Galapagos Islands?

Darwin combined the anatomical similarities of the finches with the beak adaptations for different food sources and the fact that the finches are geographically isolated on an island to explain how the species changed over time.

How did fossils contribute to Darwin's ideas about changes in species over time?

Darwin encountered fossil specimens that were anatomically similar to living species, such as the Glyptodon and the armadillo. Similarities like this supported Darwin's idea that related species evolved from a common ancestor.

Complete the statement about evolution and natural selection.

Evolution refers to a change in Alleles frequencies in a(n) Population . However, natural selection, which is a mechanism of evolution, acts on Traits , and not on genetic material directly. (Evolution is a change in allele frequencies in a population. Natural selection, which acts on traits and not genetic material, is a mechanism of evolution that can lead to changes in allele frequencies in a population over time.)

Which of the following are key elements of Darwin's theory of evolution by natural selection? Select all correct answers.

Genetic variation, fitness, and adaption are all factors in Darwin's theory of evolution. In addition, overproduction and competition are important parts of this process.

Construct an explanation as to how natural selection might produce an effect of the giraffe's neck length changing over time.

Giraffes with a longer neck variation could reach food sources in tall trees that shorter-necked giraffes could not. Those giraffes with longer necks had a better chance of survival and passed this trait on to their offspring. Over time, long-necked giraffes increased in numbers.

If the climate were to change in an environment, it is more likely that some individuals within a population will survive if

If there is greater genetic variation in the population, it is more likely that some individuals will have traits that help them survive and pass on their genes to their offspring.

Which two processes that occur during the formation of gametes contribute to increasing diversity within a population's gene pool?

Independent assortment and crossing over contribute to diversity within a population's gene pool. These processes occur during meiosis and result in the recombination of DNA.

How do mutations lead to genetic variation?

Mutations change an organism's DNA, creating more variety in the genetic material in a population.

Which statement best describes the relationship between natural selection and variation?

Natural selection acts on natural variations in a population. This variation is the result of sexual reproduction and meiosis.

Which factor is not required for natural selection to take place?

Natural selection acts on organisms that reproduce sexually and asexually. Sexual reproduction is not required for natural selection, though natural selection does favor systems with ways to exchange genetic information.

What is most likely indicated by the fact that the number of species resistant to an herbicide class never decreases?

Once herbicide resistance has evolved in a species, the trait will be maintained in the population as long as it is beneficial.

What effect did Darwin's travels to the Galápagos Islands have on the development of his theory of natural selection?

Organisms that Darwin observed on the Galápagos Islands were very closely related, but they had specific adaptations that enabled them to survive in the different, and isolated, environments of each island.

Why is the fossil record an imperfect line of evidence for evolution?

The conditions required for fossilization are difficult to meet, resulting in gaps in the fossil record. An organism or trace evidence of the organism will only be preserved under certain situations, and even then fossils can be destroyed by natural and human disturbances. This means that not every species that has ever existed has left fossilized remains, leaving gaps in the fossil record.

DNA nucleotides are said to be universal because they are the same for all known organisms. What is this evidence of? Select all correct answers.

The fact that all organisms share the same genetic code is evidence that organisms evolved from a common ancestor.

How did the work of farmers and breeders in England influence the work of Charles Darwin? Use examples to support your explanation.

The farmers and breeders that Darwin talked with practiced artificial selection in which they selected organisms with the best traits for breeding, such as the strongest plow horses, or the most productive milk cows. These traits then got passed on to the offspring. Darwin applied this concept to nature.

genetic variation

The variety of different types of genes in a species or population.

Complete this statement about how the work of other scientists influence Darwin's theory of natural selection.

The work of Lyell most helped Charles Darwin understand how bands of seashells could be found in rock strata high above sea level. (Lyell wrote Principles of Geology, in which he described movements of Earth's surface over time. This helped Darwin understand how seashell-containing rocks could be moved above the ocean surface.)

pesticide resistance

a trait possessed by certain individuals that are exposed to a pesticide and survive then reproduce and become sustainable

Adaptation

inherited characteristic that increases an organism's chance of survival

genetic fitness

the likelihood that an organism's genes will survive either by the continued life of the organism or being passed through reproduction

competition

the struggle between organisms to survive in a habitat with limited resources