Textbook Question
In science, a theory is a(n)
a. Educated guess
b. Inference based on a lack of scientific evidence
c. Idea with little experimental support
d. Body of scientifically acceptable general principles
e. Statement of fact
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Ch. 11 - Where Did We Come From?
Belk, Maier6th EditionBiology: Science for LifeISBN: 9780135214084
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Table of contents
- Ch. 1 - Can Science Cure the Common Cold?12
- Ch. 2 - Science Fiction, Bad Science, and Pseudoscience12
- Ch. 3 - Is It Possible to Supplement Your Way to Better Performance and Health?10
- Ch. 4 - Body Weight and Health10
- Ch. 5 - Life in the Greenhouse10
- Ch. 6 - Cancer10
- Ch. 7 - Fertility10
- Ch. 8 - Does Testing Save Lives?10
- Ch. 9 - Biology of Wrongful Convictions10
- Ch. 10 - Genetically Modified Organisms10
- Ch. 11 - Where Did We Come From?13
- Ch. 12 - An Evolving Enemy8
- Ch. 13 - Understanding Race11
- Ch. 14 - The Greatest Species on Earth?8
- Ch. 15 - Is the Human Population Too Large?10
- Ch. 16 - Conserving Biodiversity12
- Ch. 17 - The Human Footprint10
Belk, Maier6th EditionBiology: Science for LifeISBN: 9780135214084Not the one you use?Change textbook
Chapter 11, Problem 6
The DNA sequence for the same gene found in several species of mammals_________.
a. Is identical among all species.
b. Is equally different between all pairs of mammal species.
c. Is more similar between closely related species than between distantly related species.
d. Provides evidence for the hypothesis of common descent
e. More than one of the above is correct.
Verified step by step guidance1
Understand the concept of DNA sequence similarity: DNA sequences in genes are inherited and can accumulate mutations over time. Closely related species share a more recent common ancestor, so their DNA sequences are more similar compared to distantly related species.
Analyze the options: Option (a) states that the DNA sequence is identical among all species. This is incorrect because mutations and evolutionary divergence cause differences in DNA sequences over time.
Evaluate option (b): This option suggests that DNA differences are equal between all pairs of mammal species. This is also incorrect because evolutionary relationships determine the degree of similarity, with closer relatives having more similar sequences.
Consider option (c): This option states that DNA sequences are more similar between closely related species than between distantly related species. This is correct because closely related species share a more recent common ancestor, leading to fewer accumulated mutations.
Assess option (d) and (e): Option (d) is also correct because the similarity in DNA sequences across species supports the hypothesis of common descent. Therefore, the correct answer is (e), as more than one of the options (c and d) is correct.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
DNA Sequence Conservation
DNA sequences can be conserved across different species, particularly for essential genes. This conservation often reflects the evolutionary relationships among species, where closely related species tend to have more similar DNA sequences due to shared ancestry.
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02:13
Introduction to DNA Sequencing
Phylogenetics
Phylogenetics is the study of evolutionary relationships among biological entities, often using DNA sequences to construct evolutionary trees. It helps in understanding how species are related and can indicate that closely related species will have more similar genetic sequences compared to those that are distantly related.
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04:13Building Phylogenetic Trees Example 2
Common Descent
The hypothesis of common descent posits that all living organisms share a common ancestor. Evidence for this can be found in the similarities of DNA sequences across different species, supporting the idea that species diverged from a shared lineage over time.
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04:52Descent With Modification
Related Practice
Textbook Question
Add labels to the figure that follows, which illustrates how Mycobacterium tuberculosis evolves when it is exposed to an antibiotic.
Textbook Question
The theory of common descent states that all modern organisms
a. Can change in response to environmental change
b. Descended from a single common ancestor
c. Descended from one of many ancestors that originally arose on Earth
d. Have not evolved
e. Can be arranged in a hierarchy from 'least evolved' to 'most evolved'
Textbook Question
Marsupial mammals give birth to young that complete their development in a pouch on the mother's abdomen. All the native mammals of Australia are marsupials, while these types of mammals are absent or uncommon on other continents. This observation is an example of
a. Developmental evidence for evolution
b. Biogeographic evidence for evolution
c. Genetic evidence for evolution
d. Fossil evidence for evolution
e. Not useful evidence for evolution
Textbook Question
Even though marsupial mammals give birth to live young, an eggshell forms briefly early in their development. This is evidence that:
a. Marsupials share a common ancestor with some egg-laying species
b. Marsupials are not really mammals
c. All animals arose from a common ancestor.
d. Marsupial mammals were separately created by God
e. The fossil record of marsupial mammals is incorrect
Textbook Question
A species of crayfish that lives in caves produces eyestalks like its above-ground relatives, but has no eyes. Eyestalks in cave-dwelling crayfish are thus ________.
a. An evolutionary error
b. A dominant mutation
c. Biogeographical evidence of evolution
d. A vestigial trait
e. Evidence that evolutionary theory may be incorrect