There are multiple lines of evidence that provide support for common ancestry and evolution. Write 3-4 paragraphs describing at least three of them in detail. Provide at least one example for each line of evidence.
Answers
Answer:
First, we'll look at several types of evidence (including physical and molecular features, geographical information, and fossils) that provide evidence for, and can allow us to reconstruct, macroevolutionary events. Darwin thought of evolution as "descent with modification," a process in which species change and give rise to new species over many generations. He proposed that the evolutionary history of life forms a branching tree with many levels, in which all species can be traced back to an ancient common ancestor.
If two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous. To give one classic example, the forelimbs of whales, humans, birds, and dogs look pretty different on the outside. That's because they're adapted to function in different environments. However, if you look at the bone structure of the forelimbs, you'll find that the pattern of bones is very similar across species. It's unlikely that such similar structures would have evolved independently in each species, and more likely that the basic layout of bones was already present in a common ancestor of whales, humans, dogs, and birds.
Some homologous structures can be seen only in embryos. For instance, all vertebrate embryos (including humans) have gill slits and a tail during early development. The developmental patterns of these species become more different later on (which is why your embryonic tail is now your tailbone, and your gill slits have turned into your jaw and inner ear) squared. Homologous embryonic structures reflect that the developmental programs of vertebrates are variations on a similar plan that existed in their last common ancestor.
Evolution is the process by which a species' biology changes over time. Evolution aids in the successful transmission of genes and keeps a species alive and well. Continue reading to learn how various species have adapted to flourish in their respective surroundings. The ostrich running is a great example of evolution.
Explanation:
Anatomy and embryology:
- Darwin defined evolution as "evolutionary change", a multigenerational process in which species change and give rise to new species.
- He claimed that life's evolutionary past is a multi-leveled branching tree in which all species may be traced back to the core ancestor.
Homologous features:
- If two or more species share a physical trait, such as a sophisticated bone structure or a body plan, it's possible that they all received it from a common ancestor.
- Homologous physical traits are those that are shared due to evolutionary history (a common ancestor).
- On the exterior, the forelimbs of whales, humans, birds, and dogs all appear to be quite different. This is due to the fact that they have evolved to function in various situations.
- But, if you examine the forelimb bone structure, you'll notice that the pattern of bones is extremely similar across species.
- It's more plausible that the basic architecture of bones was already present in a common ancestor of whales, humans, dogs, and birds than that such identical features arose independently in each species.
Fossil record:
- Fossils are the preserved remnants or traces of previously existing species from the distant past. Unfortunately, the fossil record is not full or unbroken: most creatures do not fossilize, and those that do are rarely discovered by humans.
- Nonetheless, human-collected fossils provide unique insights on evolution over extended timeframes.
- How can you tell how old a fossil is? To begin with, fossils are frequently found in rocks that form strata.
- The strata serve as a form of timeline, with younger layers at the top and older ones at the bottom. Fossils found in different strata at the same site can be sorted by their placements, and "reference" strata with distinct characteristics can be used to compare the ages of fossils from other sites.
- Furthermore, radiometric dating, which monitors the radioactive decay of particular elements, can be used to roughly age fossils.