Chapter 7 Change Over Time

Maria has found a fossil. Fossils are the preserved remains or traces of ancient organisms, such as plants or animals, that are found in sedimentary rock. In this case, the impression of a leaf in the sedimentary rock indicates that it is a fossilized leaf from a past organism.

Most earthquakes take place at tectonic plate boundaries because they occur where energy is transferred to rock by the motion of tectonic plates. The movement of these plates creates stress and strain on the rocks, causing them to deform and eventually release energy in the form of an earthquake. The rock in the interior of a tectonic plate is stronger and does not deform as easily, which is why earthquakes are more likely to occur at plate boundaries where the motion and interaction of plates are more active.

The formation of the Red Sea was a result of a divergent boundary. This type of boundary occurs when two tectonic plates move away from each other. In this case, the African Plate and the Arabian Plate moved apart, creating a gap that eventually filled with water, forming the Red Sea. This process is known as seafloor spreading, where magma rises to the surface and solidifies, creating new crust and pushing the plates apart.

The term "variation" is used to describe the difference between the two spotted salamanders living in different areas. Variation refers to differences or variations within a species, such as differences in appearance, behavior, or genetics. In this case, the salamanders living in different areas may have developed different characteristics or adaptations due to their different environments, resulting in variations between them.

A sucker-like mouth is not an adaptation to prevent predators from eating a fish. While camouflage helps a fish blend into its surroundings, a spiny tail can deter predators by making it difficult to swallow the fish. The ability to change direction quickly allows a fish to evade predators. However, a sucker-like mouth is typically used for feeding and does not provide protection against predators.

A species is defined as a group of organisms that can reproduce with one another and produce fertile offspring. This means that members of the same species are able to mate and produce offspring that are capable of reproducing themselves. This reproductive compatibility is a key factor in determining whether organisms belong to the same species or not.

The most likely explanation for why the mice population changed over time is that the hawks eat more dark mice than white mice because they can see the dark mice more easily.

Anya is observing the variation within a population of kangaroos. Variation refers to the differences in traits or characteristics among individuals of the same species. In this case, Anya notices that the kangaroos of a certain species have slightly different sizes and colors, indicating that there is variation within the population. This variation can be due to genetic differences, environmental factors, or a combination of both.

The scientist can conclude that species A has a closer evolutionary relationship with species B than it does with species C. This is because the DNA similarity between species A and B is higher (97%) compared to the similarity between species A and C (95%). The higher the DNA similarity, the closer the evolutionary relationship between species.

The scenario of giraffes with longer necks surviving a dry season by eating leaves from the tops of trees and breeding more successfully is an example of natural selection. In this scenario, the longer-necked giraffes have a selective advantage because they are able to reach food that is higher up and not accessible to giraffes with shorter necks. As a result, the longer-necked giraffes are more likely to survive and pass on their genes for longer necks to the next generation. Over time, this can lead to a population of giraffes with longer necks as a result of natural selection.

Artificial selection is the process in which humans intentionally breed organisms with specific desirable traits. This can involve selecting and mating individuals with desired characteristics to produce offspring with those traits. It is a deliberate and controlled process carried out by humans to produce desired outcomes in the offspring.

Absolute dating is a method used by scientists to determine the numerical age of an object in years. This technique relies on various scientific principles and techniques such as radioactive decay and the study of rock layers. By analyzing the isotopes present in a sample or examining the position of fossils within rock layers, scientists can accurately calculate the age of an object. This information is crucial for understanding the timeline of Earth's history and the evolution of different species.

Over evolutionary time, some whales have lost or reduced the function of their tiny leg bones. This could be due to a lack of selection pressure for these structures, as they do not aid in the whale's movement or serve any other function. As a result, these structures have become vestigial, meaning they have lost all or most of their original function.

Scientific theories and scientific laws have distinct roles in understanding the natural world. Scientific theories provide explanations for why certain phenomena occur, while scientific laws describe the patterns and relationships between these phenomena. Theories are based on scientific evidence and are subject to change as new information becomes available. In contrast, laws are more general and describe what consistently happens in nature. Therefore, Samantha should summarize the difference between scientific laws and scientific theories by stating that theories explain why something happens, while laws describe what happens.

The transport of rocks by a glacier is an example of erosion because it involves the movement of material from one place to another. On the other hand, the scratching of the bedrock by these transported rocks is an example of weathering because it causes physical changes to the bedrock surface.

Fossils provide evidence for the history of life in the geologic past. Fossils are the preserved remains or traces of ancient organisms, and they can give us valuable insights into the types of organisms that lived in the past, their physical characteristics, and their interactions with the environment. By studying fossils, scientists can reconstruct the evolutionary history of different species and understand how life on Earth has changed over time. Fossils also help us understand the geological processes that have shaped the Earth's surface and the environments in which ancient organisms lived.

An adaptation is an inherited trait that improves the chances of survival and reproduction for a group of individuals in a population. This trait allows the organisms to better suit their environment and increases their likelihood of passing on their genes to the next generation. Through natural selection, individuals with beneficial adaptations are more likely to survive and reproduce, leading to the gradual change of traits in a population over generations.

An independent variable in a scientific experiment is a factor that is intentionally changed or manipulated by the researcher. This is done in order to observe the effect it has on the dependent variable, which is the factor that is measured to gather results. By manipulating the independent variable, scientists can test its impact on the dependent variable and draw conclusions about cause and effect relationships.

Changes or mutations in the genetic material cause variations within a population. Mutations are random changes in the DNA sequence, which can result in new traits or characteristics. These variations can lead to differences in survival and reproductive success, as some individuals may have traits that are better suited to the changing environment. Over time, these advantageous traits can become more common in the population through natural selection, increasing the overall fitness of the population.

The fossil record provides evidence for topics 1, 3, and 4. The fossil record allows scientists to study the relationships between extinct and living organisms (topic 1) by examining the fossils of ancient species and comparing them to modern-day species. It also provides evidence for the ancestors of living organisms (topic 3) by revealing the existence of extinct species that are believed to be the ancestors of current species. Additionally, the fossil record helps in understanding the ways that groups of species are related (topic 4) by showing the evolutionary connections between different species through the ages.