High School Biology : Understanding Evidence for Evolution

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #23 : Genetics And Evolution

How did Darwin's finches help support his theory of evolution?

Possible Answers:

The birds were different colors, which allowed for camouflage in different habitats

Only the largest birds had survived on the island, while the smaller ones went extinct

The finches all lived on different islands in order to survive

The size and shape of their beaks varied, allowing them to consume a greater variety of food sources

Correct answer:

The size and shape of their beaks varied, allowing them to consume a greater variety of food sources

Explanation:

Darwin's finches were distinct from one another due to the size and shape of their beaks. Darwin noted that these distinct beaks allowed the different birds to eat specific food groups. The varying food groups allowed the animals to coexist in the same habitat, without resorting to competing for natural food resources. Each species had evolved to occupy a unique ecological niche in order to survive with minimal competition for resources.

Example Question #24 : Genetics And Evolution

Which of the following is not an evidence for evolution?

Possible Answers:

Fossil record

All of these are evidence of evolution

Common ancestor organisms

Vestigial structures

Natural selection

Correct answer:

All of these are evidence of evolution

Explanation:

Evolution is a theory that accounts for the changing and transformation of organisms throughout history. For evolution to take place, mutations must occur and change the genetic identity of a population. Essentially, evolution is evidenced by changes in genetic diversity and allele frequency. Each of the answer choices contributes towards the theory of evolution.

Natural selection was coined by Darwin, whose work helped with the theory, and describes the tendency for traits that aid in survival to become more prevalent in a population. Vestigial structures are organs in modern organisms that serve no purpose in increasing biological fitness, but may have been useful to ancestral species in history. Common ancestor organisms are different species that share genetic information with modern species, suggesting that genetic changes in the historic species may have produced the modern species. The fossil record provides genetic material and physical evidence of historic species to use for comparison with modern organisms.

Example Question #1 : Understanding Evidence For Evolution

Which of the following is NOT an example of evidence supporting the endosymbiotic theory?

Possible Answers:

All of these are correct.

The genes in the nucleus of a cell are not enough to make a functional mitochondrion; mitochondrial genes are also necessary.

Mitochondria have their own ribosomes, which are 70s.

Mitochondria contain their own DNA, which is a single circular chromosome.

Mitochondria and other plastids multiply via binary fission.

Correct answer:

All of these are correct.

Explanation:

All of these are true. There is lots of evidence supporting the endosymbiotic theory. The mitochondrial genes, in addition to the genes in the nucleus, are also needed to make a functional mitochondrion. These genes are contained in a singular circular chromosome, the same way bacterial genes are organized. Also, when translating their mRNA, they use the same ribosome structure as prokaryotes (70s). The mitochondria are not replicated the same way as other organelles or structures; they undergo binary fission.

Example Question #2 : Understanding Evidence For Evolution

Which of the following is true regarding mitochondrial DNA?

Possible Answers:

It is found in the mitochondria and in humans, it is passed down only through the maternal line, from a mother to her children.

It is found in the nucleus and in humans, it is passed down only through the paternal line, from a father to his children.

It is found on a plasmid in the nucleus.

It is found in the nucleus and in humans, it is passed down only through the maternal line, from a mother to her children.

It is found in the mitochondria and in humans, it is passed down only through the paternal line, from a father to his children.

Correct answer:

It is found in the mitochondria and in humans, it is passed down only through the maternal line, from a mother to her children.

Explanation:

The correct answer is that mitochondrial DNA is found in the mitochondria, where it takes the form of a plasmid, or ring-shaped structure characteristic of bacterial DNA. (This provides evidence in favor of the endosymbiotic theory.) Furthermore, in humans and in many other organisms, mitochondrial DNA is passed down solely through the maternal line. Note that the answer choice "It is found in a plasmid in the nucleus" is inherently non-sensical; plasmids are characteristic of prokaryotes, which do not have nuclei, as they do not have membrane-bound organelles.

Example Question #3 : Understanding Evidence For Evolution

What's the difference between homologous and analogous structures?

Possible Answers:

There is no difference between homologous and analogous structures

Homologous structures result from a common ancestor; analogous structures result from repetitive usage by the individual (and are passed to offspring)

Homologous structures result from a common ancestor; analogous structures result from convergent evolution 

Homologous structures result from repetitive usage by the individual (and are passed to offspring); analogous structures result from a common ancestor

Homologous structures result from convergent evolution; analogous structures result from a common ancestor

Correct answer:

Homologous structures result from a common ancestor; analogous structures result from convergent evolution 

Explanation:

Homologies are physical similarities resulting form common ancestry.  This is the reason that related species share similar features.  Therefore, homologous structures are anatomical similarities in organisms due to a shared ancestry.  On the other hand, analogous structures are the result of convergent evolution.  Convergent evolution is defined as the evolution of similar anatomical features in independent evolutionary lineages. In response to a changing environment, natural selection favored animals with similar traits or features that evolved independently as a result of  adaptation to environmental alterations. 

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