Concept explainers
The unexpected discovery that humans interbred with Neanderthals was a triumph for the experts who developed the techniques for extracting, isolating, and sequencing ancient DNA. But perhaps the most stunning revelation made possible by ancient DNA was the discovery of the Denisovans, a hominin species whose existence would still be unknown if not for analysis of its ancient DNA. The fossil fragments from which the DNA was extracted were too few, too small, and too nondescript to have even been recognized as belonging to a previously unknown species. A newfound ability to identify new extinct species on the basis of DNA alone raises the intriguing possibility of future discovery of other previously unsuspected species, hommin and otherwise.
Like Neanderthals, Denisovans left a genetic trace in modern humans. One example is the Denisovan gene variant that helps Tibetans live at high altitude. Additionally, the people native to New Guinea and other Pacific islands carry a substantial number of Demsovan sequences. Almost 5% of the genome of these people is of Demsovan origin. This finding suggests that Denisovans interbred with the ancestors of Pacific Islanders, either in mainland Asia before the islands were first cotonized by people, or later, if Denisovans were somehow able to get to multiple islands.
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Biology: Life on Earth with Physiology (11th Edition)
- 8) Each of the observations provides evidence that supports the idea of common ancestry and evolution. Which one is from the field of molecular biology? A) Mammals have two openings in the skull behind each eye socket, whereas reptiles and bird only have one opening. B) DNA analysis shows that the DNA of Neanderthals is more similar to the DNA of non‑African humans than that of Africans. C) Two closely related but distinct species of squirrels inhabit the north and south rims of the Grand Canyon. D) The embryos of both birds and mammals divide in a radial cleavage pattern instead of a spiral cleavage pattern present in insects.arrow_forwardIn the book, Jurassic Park, by Michael Crichton, scientists are able to reconstruct dinosaurs by getting dinosaur DNA from a mosquito that had been well-preserved in amber since the era of dinosaurs. Do you believe this can actually happen in real life? Why?arrow_forwardCat DNA is much more similar to dog DNA than to tortoise DNA. Why? (a) Cats and dogs are both carnivores and take in similar nutrients. (b) Cats and dogs have lived together with humans for a long period of time, so they have grown more similar. (c) Cats and dogs have more offspring during their lifetime than tortoises have, so their DNA changes less rapidly. (d) Cats and dogs have a common ancestor that is more recent than the common ancestor of cats and tortoises.arrow_forward
- Advances in biotechnology have revolutionized the study of ancient remains. In Ötzi's case, a genetic study showed that his DNA most closely matched up with people that currently live in Sardinia. One hypothesis for this is that at Ötzi's time, a group of people with similar DNA spread throughout Europe including Sardinia. Sardinia is somewhat isolated so the DNA of the population living there has changed very little since that time. On mainland Europe, where his remains were found, there was more mixing of populations so there have been changes to the DNA profiles of the people living in that region. Questions: 1.) Based on the genetic results, do you think Ötzi should be considered Sardinian even though he lived in the Alps? Why or why not?arrow_forwardThere are two hypotheses to explain the pattern of Human Evolution: 1) Progressive Evolution of a Single Lineage ; 2) Evolutionary Radiation Which of these hypotheses are supported by evidence, and briefly explain why? Please explain in detailsarrow_forwardFill the blank New genes can arise during evolution through: (i) exonshuffling, which can alter the domain structure of proteins;(ii) duplication and divergence that generates gene families;and (iii)_______ mutations in intergenic DNA sequences.arrow_forward
- create a phylogeny of human evolution. It should include all known hominids beginning with the earliest and ending with modern Homo sapiens. In your version of a future, humans will create a phylogeny of human evolution. It should include all known hominids beginning with the earliest and ending with modern Homo sapiens and your version of a future human. The requirement is to put the genus and species name of the hominid, beginning with the earliest one, which is Sehelanthropus tchadensis, in the phylogeny along with its dating age.arrow_forwardSome people think that many of our uniquely human traits arose by sexual selection. Over thousands of years, women attracted to charming, witty men perhaps prompted the development of human intellect beyond what was necessary for mere survival. Men attracted to women with juvenile features may have shifted the species as a whole to be less hairy and softer featured than any of our simian relatives. Can you think of a way to test these hypotheses?arrow_forwardEven though paleontologists and anthropologists are continually finding new fossils, there is still a lack of fossils overall. Explain.arrow_forward
- The meat eaters who existed 1.5 million years ago were called ______.a) Homo habilis b) Hominids c) Homo erectus d) Homo sapiensarrow_forward1a) How do the events surrounding the Peppered Moth during the industrial era in Great Britain support the theory of natural selection? 1b) There exist several categories of evidence that lend credence to the interrelated nature of all organisms alive today. Describe two (2) pieces of evidence that support the theory of evolution (and the notion of a universal common ancestor). 1c) What is leading to the development of antibiotic-resistance bacteria? Why should we be concerned?arrow_forwardNearly 4 million years ago, two or three hominins left their footprints across the savanna of modern day Tanzania, clear evidence that… Group of answer choices A-hominins were quadrupedal 4 million years ago, prior to the adaptation of walking on two feet B-the Hominins that left the footprint impressions habitually walked bipedally C-members of the evolutionary lineage that include our own species are capable of running at speeds of nearly 35 miles per hour D-Australopithecus afarensis males weighed between 150 – 190 pounds E-volcanic activity along the Kilombero fault line caused a mass extinction event around 4 million years agoarrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning