Examples of fossil record in the following topics:
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- Because not all animals have bodies which fossilize easily, the fossil record is considered incomplete.
- The number of species known about through the fossil record is less than 5% of the number of species alive today.
- The fossil record is very uneven and is mostly comprised of fossils of organisms with hard body parts, leaving most groups of soft-bodied organisms with little to no fossil record.
- Groups considered to have a good fossil record, including transitional fossils between these groups, are the vertebrates, the echinoderms, the brachiopods, and some groups of arthropods.
- Romer's gap is an example of an apparent gap in the tetrapod fossil record used in the study of evolutionary biology.
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- The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record.
- Fossils, along with the comparative anatomy of present-day organisms, constitute the morphological, or anatomical, record.
- The resulting fossil record tells the story of the past and shows the evolution of form over millions of years.
- Footprints are examples of trace fossils, which contribute to the fossil record.
- Synthesize the contributions of the fossil record to our understanding of evolution
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- The detailed fossil record of horses has provided insight into their evolutionary progress.
- The resulting fossil record tells the story of the past and shows the evolution of forms over millions of years.
- Highly
detailed fossil records have been recovered for sequences in the
evolution of modern horses.
- The fossil record of horses in North America
is especially rich and contains transition fossils: fossils that show intermediate stages between earlier and later forms.
- The fossil record shows several adaptive radiations in the horse lineage, which is now much reduced to only one genus, Equus, with several species.
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- Evidence for evolution has been obtained through fossil records, embryology, geography, and molecular biology.
- The resulting fossil record tells the story of the past and shows the evolution of form over millions of years.
- For example, scientists have recovered highly-detailed records showing the evolution of humans and horses .
- (a) In this display, fossil hominids are arranged from oldest (bottom) to newest (top).
- Explain how the fossil record has aided in the development of the theory of evolution
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- Paleontologists have identified five strata in the fossil record that appear to show sudden and dramatic losses in biodiversity known as mass extinctions.
- The fossil record of the mass extinctions was the basis for defining periods of geological history, so they typically occur at the transition point between geological periods.
- The Ordovician-Silurian extinction event is the first-recorded mass extinction and the second largest.
- The Cretaceous-Paleogene (K-Pg) boundary marked the disappearance of the dinosaurs in fossils, as well as many other taxa.
- Extinction occurrences, as reflected in the fossil record, have fluctuated throughout earth's history.
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- The evolution of viruses is speculative as they do not fossilize; biochemical and genetic information is used to create virus histories.
- When exploring the evolutionary history of most organisms, scientists can look at fossil records and similar historic evidence.
- However, viruses do not fossilize, so researchers must conjecture by investigating how today's viruses evolve and by using biochemical and genetic information to create speculative virus histories.
- Finding a common ancestor for viruses has proven to be far more difficult, especially since they do not fossilize.
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- Evidence from the fossil record and from a comparison of human and chimpanzee DNA suggests that humans and chimpanzees diverged from a common hominoid ancestor approximately 6 million years ago.
- In the past several years, however, many new fossils have been found.
- The fossil, informally called "Toumai," is a mosaic of primitive and evolved characteristics.
- To date, it is unclear how this fossil fits with the picture given by molecular data.
- The scientists who discovered the first fossil found that some other scientists did not believe the organism to be a biped (thus, it would not be considered a hominid).
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- The fossil record provides evidence of the first tetrapods: now-extinct amphibian species dating to nearly 400 million years ago.
- Acanthostega was aquatic; fossils show that it had gills similar to fishes.
- In 2006, researchers published news of their discovery of a fossil of a "tetrapod-like fish," Tiktaalik roseae, which seems to be an intermediate form between fishes having fins and tetrapods having limbs .
- The recent fossil discovery of Tiktaalik roseae suggests evidence for an animal intermediate to finned fish and legged tetrapods.
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- A substantial hurdle is the difficulty of working out fossil ages.
- Paleontologists rely on stratigraphy to date fossils.
- Stratigraphy is the science of understanding the strata, or layers, that form the sedimentary record.
- If a fossil is found between two layers of rock whose ages are known, the fossil's age is thought to be between those two known ages.
- Misleading results can occur if the index fossils are incorrectly dated.
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- Although probable prokaryotic cell fossils date to almost 3.5 billion years ago, most prokaryotes do not have distinctive morphologies; fossil shapes cannot be used to identify them as Archaea.
- Instead, chemical fossils of unique lipids are more informative because such compounds do not occur in other organisms.
- Microbial mats or large biofilms may represent the earliest forms of life on earth; there is fossil evidence of their presence starting about 3.5 billion years ago.
- Fossilized microbial mats represent the earliest record of life on earth.
- (b) These fossilized stromatolites, found in Glacier National Park, Montana, are nearly 1.5 billion years old.