Question 1

Changes that occur at the genetic level in populations are classified as ________.

Accepted Answer

Changes at the genetic level in populations that result in changes in allele frequencies over time are classified as microevolution. Chemical evolution refers to the formation of complex molecules from simpler ones, gradualism is a model of evolution that suggests that changes occur slowly and steadily over time, and macroevolution refers to large-scale evolutionary changes such as the development of new species or groups.

Question 2

With the problems related to fossilization listed in the text,which of these creatures would be least likely to be successfully fossilized?

Accepted Answer

Plants are generally less likely to be successfully fossilized due to their soft tissues and lack of hard structures like bones or shells. Therefore, the rose flower would be the least likely option to be successfully fossilized. The other options all have hard structures that may fossilize better.

Question 3

You,as a cell biologist,discover that there is strong evidence that chloroplasts,found in plant and algal cells,are descended from bacteria but not eukaryotes.What theory would explain this finding?

Accepted Answer

The endosymbiont theory proposes that mitochondria and chloroplasts were once free-living prokaryotes that were engulfed by eukaryotic ancestors and developed a symbiotic relationship. The strong evidence that chloroplasts are descended from bacteria supports the endosymbiont theory.

Question 4

Different forms of a gene are called ________.

Accepted Answer

Different forms of a gene are called alleles. Proteins are not forms of genes, but rather products of genes. Genome refers to the entire set of an organism's genetic information. Chromosomes are structures that contain many genes.

Question 5

Which of the following is not a primate characteristic?

Accepted Answer

Primates are known for having small litter sizes, often only giving birth to one offspring at a time. Larger litter sizes are more commonly found in other mammalian groups such as rodents or carnivores. Rotating shoulders, stereoscopic vision, and flattened nails instead of claws are all key primate characteristics.

Question 6

Which of these trends occurred first in hominin evolution?

Accepted Answer

Bipedalism is considered the oldest trend in hominin evolution, dating back to more than 6 million years ago with Sahelanthropus tchadensis. Other trends such as tool use, larger brains, and writing occurred much later in hominin evolution.

Question 7

Today's atmosphere on Earth is made up of nitrogen,oxygen,carbon dioxide,and water.According to all models,which of these was largely absent 3.8 billion years ago?

Accepted Answer

Oxygen was largely absent 3.8 billion years ago according to all models.

Question 8

Which of the following refers to the ability of early hominins to walk on two feet?

Accepted Answer

Bipedalism refers to the ability to walk on two feet, which is a defining characteristic of early hominins. Choice B (digitigrade) refers to animals that walk on their toes, and choice C (plantigrade) refers to animals that walk on their entire foot. Choice D (tetrapedal) refers to animals that walk on four limbs.

Question 9

Which of the following is true of chimpanzees compared with humans?

Accepted Answer

Chimps have opposable big toes, while humans do not. The other options are not true as humans have larger patellae, straighter spines, and larger shoulder blades compared to chimpanzees.

Question 10

The relative number of reproductively viable offspring produced by individuals is called ________.

Accepted Answer

Fitness refers to the number of offspring an individual produces that are able to reproduce and pass on their genes to the next generation. It is a measure of how well an organism is adapted to its environment and its ability to survive and reproduce.

Question 11

Almost all cacti are native to the Americas,but there is a small,relatively uncommon group of plants closely related to cacti native to tropical western Africa.How can we explain this given the information in this chapter?

Accepted Answer

The fact that there are cactus-like plants in Africa suggests that there was once a land connection between the Americas and Africa, allowing for the exchange of plant species. Option A is unlikely as it is improbable for plants to survive such a long journey across the ocean. Option B is also unlikely as divergent evolution typically takes millions of years to occur, and the split between African and American cacti is not that old.

Question 12

Which of the following is a correctly written scientific name?

Accepted Answer

Option A represents a scientific name that includes the genus and species of the organism written in italics with the genus capitalized and the species name in lowercase. This is the correct format for a scientific name. Option B has the correct genus and species but it should be italicized and written as Homo sapiens. Option C is the common housefly and is not written correctly as a scientific name. Option D is the scientific name for the red maple and is written correctly, but it is not the only option that is written correctly.

Question 13

Which of the following species is most likely to be infected with the newly discovered human virus Zeta 1?

Accepted Answer

As it is a newly discovered human virus, the species most likely to be infected would be one that is closely related to humans. Orangutans share around 97% of their DNA with humans, making them the best choice for potential infection with a human virus. Mice, pottos, and kangaroos are not as closely related to humans and are therefore less likely to be infected with a human virus.

Question 14

Which suggests that life evolved from chemicals slowly increasing in complexity over a period of millions of years?

Accepted Answer

Chemical evolution is the theory that suggests life evolved from simple chemicals over time, gradually increasing in complexity. This theory is supported by evidence from studies of the early Earth and the reactions that could have occurred to create the building blocks of life.

Question 15

Which of the following is true of the evolution of humans?

Accepted Answer

The process of human evolution is complex and has seen multiple dead ends, including various hominid species that became extinct.
 
Answer: B is not correct, as humans did not evolve from chimpanzees; rather, humans and chimpanzees share a common ancestor that lived around six to seven million years ago.
 
Answer: C is partially correct, as organs did evolve in concert to a certain extent, but this is not necessarily a defining characteristic of human evolution.
 
Answer: D is also not correct, as humans and apes share a common ancestor that lived around 20 million years ago, and humans did not split off from apes until much more recently, around 6-7 million years ago.

Question 16

Which of the following is one method of acquiring genetic changes in a population caused by a change in the DNA?

Accepted Answer

Mutations are changes in an organism's DNA that can lead to genetic variation in a population. Mutations can occur spontaneously or be caused by environmental factors such as radiation or chemicals.

Question 17

Which refers to the different rates at which various traits evolve?

Accepted Answer

Mosaic evolution refers to the idea that different traits may evolve at different rates, leading to a mosaic of traits that do not necessarily co-evolve together. This can be seen in the evolution of various groups such as primates where certain traits like brain size may evolve at a faster rate compared to other traits like body size.

Question 18

Which can drive microevolution and occurs when individuals move in and out of populations?

Accepted Answer

Gene flow occurs when individuals move in and out of populations, bringing new alleles with them. This can have a significant impact on the genetic diversity of a population and can drive microevolutionary changes over time. The other options (speciation, founder effect, and adaptation) can also drive microevolution, but they do not specifically involve the movement of individuals into or out of populations.

Question 19

The adult human jawbone,or mandible,arises embryonically from a gill arch.The arch and the mandible are said to be ________.

Accepted Answer

Homologous structures are structures that have a similar evolutionary origin but may have different functions in different organisms. In this case, the embryonic development of the mandible from a gill arch indicates that it has a similar evolutionary origin to gill arches, which are present in fish and other aquatic organisms. Therefore, the mandible and gill arches are homologous structures.

Question 20

A protein similar to the human Rh blood factor (due to a specific set of genes)can be found in many animals.In which of the following is it least likely to be found?

Accepted Answer

Rh factor is not found in birds, such as parrots, and is primarily found in mammals.

Quiz 22: Evolution and Our Heritage