Biological Evolution Exam 1

A theory is a cohesive and rigorously tested related set of hypotheses that describes a large section of scientific endeavor. This means that a theory is not just a guess or an assumption, but rather a well-supported and extensively tested explanation for a particular phenomenon or set of phenomena. It is based on empirical evidence and observations, and it provides a framework for understanding and predicting the behavior of the physical world. Theories are constantly being refined and updated as new evidence emerges, and they play a crucial role in advancing scientific knowledge and understanding.

Nodes on a phylogeny represent common ancestral populations for the species at the tips of the branches. This means that each node represents a point in evolutionary history where a common ancestor gave rise to multiple descendant species. The branches leading from the nodes represent the evolutionary relationships and diversification of these descendant species over time. Therefore, it is true that nodes on a phylogeny represent common ancestral populations for the species at the tips of the branches.

Evolution refers to the process of change in a biological population over time. It involves the gradual accumulation of genetic variations within a population, leading to the emergence of new species and the extinction of others. This process is driven by mechanisms such as natural selection, genetic drift, and mutation. Evolution is not limited to individual organisms or changes within a specific geographical area, but encompasses the broader concept of how populations and species change and adapt over generations.

This statement is false because extinct species can be included on phylogenies. Phylogenies are diagrams that show the evolutionary relationships between different species, including both extant (living) and extinct species. By analyzing fossil records and genetic data, scientists can determine the evolutionary history and placement of extinct species on phylogenetic trees. Including extinct species on phylogenies helps us understand the diversity and evolution of life on Earth.

The argument of "not enough instruction time" is not a major argument in the legal battles regarding the teaching of creationism and intelligent design in US public schools. The main arguments revolve around the separation of Church and State, as teaching these subjects can be seen as promoting a specific religious belief, and the non-scientific nature of creationism and intelligent design, as they lack empirical evidence and scientific support. However, the argument about limited instruction time is not typically a central concern in these legal battles.

The statement is true because the term "fish" is used to refer to a wide variety of species that do not share a common ancestor. In taxonomy, a valid taxon should include all descendants of a common ancestor, but this is not the case with fish. Some fish species are more closely related to tetrapods (such as amphibians, reptiles, birds, and mammals) than they are to other fish species. Therefore, the term "fish" is not a valid, single taxon but rather a polyphyletic grouping.

The sister taxon of the Hyraxes is the group that includes Elephants and Manatees because they share a more recent common ancestor with Hyraxes than the other options.

Metamorphic rocks are the least important when trying to determine the relative date of fossils because they are formed through the process of intense heat and pressure, which can alter the original structure and composition of the rocks and any fossils within them. As a result, it becomes difficult to accurately determine the age of fossils preserved in metamorphic rocks. Sedimentary rocks, on the other hand, are formed through the accumulation and cementation of sediments over time, making them more reliable for dating fossils. Igneous rocks are formed from the solidification of molten magma and can also provide important clues about the age of fossils.

Whales share a common ancestor with hippopotamuses, horses, lungfish, mushrooms, and bacteria. This means that at some point in the past, all of these organisms diverged from a common ancestor and evolved into their respective species. This is supported by evidence from comparative anatomy, genetics, and the fossil record, which show similarities and shared traits between whales and these organisms.

A trait that has lost its original function, but is still present in an organism as an unused remnant is known as vestigial.

Fossil dates are quite accurate, but often not very precise. This means that the estimated age of fossils is generally close to the actual age, but the measurements may not be consistent or have a narrow range. This could be due to various factors such as limitations in dating techniques, uncertainties in the fossil record, or the presence of multiple events or processes that can affect the age determination.

Some relationships are depicted as polytomies because there is not enough data available to fully determine the relationships between the included species. This means that the relationships cannot be accurately represented in a fully resolved topology, and instead, multiple branches may emerge from a single node, indicating uncertainty in the relationships.

The half-life of a radioactive element is the time it takes for half of the initial amount of the element to decay. In this case, the rock started with 200 ug per kg of the element and after 100 million years, it only has 6.25 ug per kg. This means that half of the initial amount (100 ug per kg) decayed in 100 million years. Therefore, the half-life of this element is 100 million years divided by 2, which is 50 million years.

A phylogram is a type of phylogenetic tree that includes branch lengths proportional to the amount of evolutionary change. This allows for the visualization of the amount of genetic divergence between species. Without the actual options provided in the question, it is not possible to determine which phylogeny is a phylogram.

The transition to a bipedal gait in therapod dinosaurs was critical for the origin of flight. This shift from a quadrupedal to a bipedal posture allowed for the development of adaptations necessary for flight, such as the elongation of the forelimbs into wings. Bipedalism freed up the forelimbs, enabling them to evolve into wings and facilitating the development of flight in later dinosaur descendants.

Horses and rhinoceroses are both members of the order Perissodactyla, which includes odd-toed ungulates. They share similar characteristics such as having an odd number of toes and a similar dental structure. This indicates a close evolutionary relationship between horses and rhinoceroses. On the other hand, cows, hippopotamuses, antelopes, and deer belong to different orders and are not as closely related to horses as rhinoceroses are.

Igneous rocks are the easiest to directly date using the radioactive half-lives of the isotopes they contain because they form from the solidification of molten material, allowing for the isotopes to be effectively trapped within the rock. Sedimentary rocks are formed from the accumulation of sediments and may contain older material, making direct dating more difficult. Metamorphic rocks are formed from the transformation of existing rocks under high pressure and temperature, which can reset the radioactive clock, making direct dating less reliable.

The correct answer is "New mutation in HIV that allow it to circumvent the human immune system." This represents evolution caused by a transformational process because it involves the development of a new trait (mutation) in the HIV virus that allows it to overcome the human immune system. This is a transformational process as it leads to the emergence of a new characteristic in the population of HIV viruses.

not-available-via-ai

In the evolution of the horse lineage, two trends can be observed. Firstly, there is a reduction in the number of digits on appendages. This can be seen as horses today have a single toe, while their ancestors had multiple toes. Secondly, there is an overall increase in size. Over time, horses have become larger in size compared to their earlier ancestors. These trends reflect the evolutionary changes that have occurred in the horse lineage over time.

The correct answer is Relidactyla, a group that includes Ruminants, Hippopotamuses, and Cetaceans. This classification is valid because it includes organisms that share a common ancestor and have similar characteristics. Ruminants, Hippopotamuses, and Cetaceans are all part of the same branch on the phylogenetic tree, indicating their close evolutionary relationship.

Character 7 is a synapomorphy for the group made up of Species C, D, E, and F because it is the only character that is present in all four species and absent in the other two species (A and B). This character is a shared derived trait that evolved in the common ancestor of Species C, D, E, and F and is inherited by all descendants of that ancestor.

Slime molds would be the best group of organisms to select as a model for the origin of multicellularity because they exhibit a range of different forms of multicellularity, including both unicellular and multicellular stages in their life cycle. This allows scientists to study the transition from unicellularity to multicellularity and understand the evolutionary processes involved. Additionally, slime molds have a relatively simple structure and genome, making them more accessible for research and experimentation.

Variational processes refer to any factors or mechanisms that introduce variation within a population. These processes can include genetic mutations, environmental changes, or random events. When variational processes decrease, it means that there is a reduction in the amount of variation within the population. This can lead to a decrease in diversity, as there are fewer different traits or characteristics present.

The U.S. Army's basic training program is an example of change caused by a transformational process because it involves a comprehensive training program that aims to improve the abilities and aptitude of recruits. Through technical, physical, and mental training, the recruits undergo a transformation and experience a significant increase in their skills and capabilities. This process involves a deliberate effort to bring about a positive change in the recruits' abilities, making it a clear example of a transformational process.

Humans, Chimps, Bonobos, Gorillas, and Orangutans belong to the Family Hominidae (the hominids). This family includes all the extant members of the great apes, which are the closest living relatives to humans. They share common ancestry and have similar physical and genetic characteristics. The other options, Subtribe Hominina, Order Primates, and The anapsids, do not encompass all the mentioned species and are not accurate in representing the extant members of these primates.

Character 6 is a symplesiomorphy for the group made up of Species B, C, D, E, and F because it is shared by all of these species and also present in the outgroup (Species A). A symplesiomorphy is a shared ancestral character, meaning it was present in the common ancestor of the group. In this case, Character 6 is present in both the ingroup and outgroup, indicating that it is an ancestral trait that has been retained in the group.

Day Age Creationism is the best fit for the given description. Day Age Creationism posits that the six creative periods described in the Bible were not literal 24-hour days, but rather represent long periods of time, possibly millions of years. This explanation aligns with the statement that the time for each of the creative periods may have spanned many millions of years.

Green algae are considered the closest relatives of plants because they share many similarities in terms of cellular structure, photosynthetic pigments, and reproductive processes. Both green algae and plants contain chlorophyll a and b, which allows them to carry out photosynthesis. They also have similar cell walls composed of cellulose. Additionally, green algae and plants reproduce through the alternation of generations, where they have both a multicellular diploid and haploid stage in their life cycle. These shared characteristics suggest a close evolutionary relationship between green algae and plants.

The diagram and provided information indicate that the rock layer labelled with the star is older than 280 million years.

Bird feathers most likely evolved first for the function of display. Feathers play a crucial role in attracting mates and establishing dominance within a species. They can be used for courtship displays, territorial displays, or to intimidate rivals. While feathers also provide insulation, flight, and aid in respiration, the primary function of feathers evolving first is for display purposes.

Pakicetus is the correct answer because it is an extinct genus of early whales that lived approximately 50 million years ago. Fossil evidence suggests that Pakicetus had features that are similar to both whales and land-dwelling mammals, making it a transitional form in the evolution of whales. This suggests that Pakicetus is the most closely related extinct taxon to modern whales. Archaeopteryx is an extinct bird species, Pliohippus is an extinct horse species, and Sinornis is an extinct bird species, none of which are closely related to modern whales.

The correct answer is 4.5 billion years ago, based on direct radioactive dating of the oldest igneous rocks. This method involves measuring the decay of radioactive isotopes in rocks to determine their age. By analyzing the isotopes present in the oldest igneous rocks on Earth, scientists have determined that the Earth formed approximately 4.5 billion years ago. This method provides a direct and reliable way to determine the age of the Earth.

Tokogeny refers to the process of reproduction within a species. In the given options, relationships between species of bacteria would exhibit high levels of tokogeny as bacteria reproduce asexually through binary fission, resulting in rapid population growth within a species. Additionally, relationships within a species of mammal would also exhibit high levels of tokogeny as mammals reproduce sexually and have internal fertilization, leading to the production of offspring within the same species.

Genes are considered orthologous when they are derived from a common ancestor through speciation events. In the given diagram, gene 2 and gene 4 are orthologous because they are found in different species (represented by the different boxes) but share a common ancestor (represented by the same color of the gene). Therefore, the correct answer is 2 and 4.

The correct answer is 3.3 billion years ago because the evidence provided, which is the dramatic increase in the oxides found in sedimentary rocks, supports this date. This evidence suggests that photosynthesis was occurring at this time, as the process of photosynthesis releases oxygen as a byproduct, which would lead to an increase in oxides in sedimentary rocks.

The correct answer is 5.5 million years ago. This is the estimated date of origin for the hominin group, which includes modern humans and their closest relatives. This date is based on fossil evidence and genetic studies, which suggest that the hominin lineage diverged from other primates around this time.

This statement is not accurate. Ethical decisions cannot always be made solely through scientific experiments. Ethical considerations involve a variety of factors, including cultural values, personal beliefs, and social norms, which cannot always be measured or determined through scientific experiments alone. Additionally, not all ethical questions can be answered through scientific methods, as some may involve subjective judgments or individual perspectives. Therefore, it is incorrect to suggest that all ethical decisions should be based solely on well-designed scientific experiments.

Homoplasy refers to the occurrence of similar traits in different species that are not inherited from a common ancestor. In the given phylogeny, Character 4 and Character 6 exhibit homoplasy because they have the same trait (0) in Species A and Species B, which are not closely related. This suggests that the similarity in these characters is not due to common ancestry but rather due to convergent evolution or other factors.

The correct answer is Triassic, 250 mya. The Triassic period is the first period of the Mesozoic era, which occurred approximately 250 million years ago (mya). This period followed the Permian period and preceded the Jurassic period. It is known for the diversification of reptiles and the emergence of the first dinosaurs.

The endosymbiosis hypothesis is supported by several lines of evidence. One piece of evidence is that mitochondria and chloroplasts have their own genome, which is separate from the nuclear genome of the cell. This suggests that they were once independent organisms that were engulfed by a host cell. Another piece of evidence is that mitochondria and chloroplasts have a double membrane, which is consistent with the idea that they were engulfed by a host cell. Additionally, the genes in both mitochondria and chloroplasts are more closely related to bacterial genes than to any eukaryotic genes, indicating a shared evolutionary history with bacteria.

The answer "800-600 million years ago, Relative dating of fossils in sedimentary rocks" suggests that the origin of complex animals occurred during this time period based on the evidence of relative dating of fossils in sedimentary rocks. Relative dating is a method used to determine the age of fossils by comparing their positions in the rock layers. By examining the fossils found in sedimentary rocks, scientists can estimate the age of the rocks and infer the time period when complex animals originated.

The correct answer is Cambrian, 540 mya. The Paleozoic era is divided into several periods, with the Cambrian being the first period. The Cambrian period began approximately 540 million years ago (mya). Therefore, the name of the first period and its beginning date for the Paleozoic era is Cambrian, 540 mya.

The correct answer is Tertiary, 65 mya. The Tertiary period is the first period of the Cenozoic era, which began approximately 65 million years ago (mya). This period followed the extinction event that wiped out the dinosaurs and marked the rise of mammals. It lasted until around 2.6 million years ago. Therefore, Tertiary is the correct answer for the first period in the Cenozoic era, and 65 mya is the correct beginning date for this period.