
Concept explainers
To determine: The evidence that shows that the most recent common ancestor of chimpanzees and humans was much more arboreal than modern humans.
Introduction: Humans are believed to have evolved from the last universal common ancestor of all the living organisms. Chimpanzees and humans share a common ancestor from where hominins diverge to give rise to modern humans.

Explanation of Solution
According to the fossil records, Chimpanzees and humans have evolved from the same common ancestor. Humans have evolved from apes and the most common relative of humans are chimpanzees. About 7 million years ago (mya), hominins diverged from chimpanzees to evolve into modern day humans. The members of the hominin clade include Sahelanthropus, Orrorin, and Ardipithecus. A 4.4 million year-old fossil deposit of Ardipithecus ramidus in Ethiopia suggested that they had many apelike features including opposable big toe which are adaptations for climbing.
About 3.5 Mya, the fossil of Australopithecus afarensis shows ancestral features common to the ancestors of humans and chimpanzees. These features include, lower face, long arms relative to the legs, and the limb structure shows that these species climb trees along with walking.
The first fossilized footprints have been found about 3.5 Mya in Tanzania. So, it can be assumed that before this, the common chimpanzees- human ancestor lived more arboreal life.
One of the early species of Homo was Homo habilis which resembled modern human had limbs which suggested that they had an ability to climb.
To explain: The change in the conditions of Africa, which selected for a less arboreal lifestyle.
Introduction: Humans are believed to have evolved from the last universal common ancestor of all the living organisms. Chimpanzees and humans share a common ancestor from where hominins diverge to give rise to modern humans.

Explanation of Solution
The change in the climatic conditions leads to various drastic changes in the lifestyle of species. The earlier human ancestors were adapted to live an arboreal life because of the wet climate of Africa. The change in temperature and precipitation has caused the land to become dry. The hominins now started living on land instead of trees. This change favored walking instead of climbing.
The other theory which supports this is that the competition in arboreal life increased. This caused some of the species to leave trees and start living on land. Earlier evidence showed that the member of hominins such as Australopithecus afarensis was adapted to climb trees as well as walking. Now, natural selection comes into play and selects walking over climbing which is then passed on to next generation.
This can be explained on the basis of “survival of the fittest”, as the competition increased, the more fitted organ is favored and is selected by natural selection. In this case, walking was preferred over climbing as the climatic conditions of Africa were more suited for walking. This also helped the species to pluck fruits and also running away from prey. The drier environment also leads to loss of body hair to keep the body temperature low.
To explain: The cause of changes that did not evolve in chimpanzee’s lineage.
Introduction: Humans are believed to have evolved from the last universal common ancestor of all the living organisms. Chimpanzees and humans share a common ancestor from where hominins diverge to give rise to modern humans.

Explanation of Solution
Humans and chimpanzees are believed to have evolved from a common ancestor. They two belong in the same group called apes. After several evolutions, human ancestor diverged from chimpanzees to evolve into modern day human. Human and chimpanzees are related cousins; humans did not evolve from chimpanzees. This fact is the main reason for the evolution of human becoming less arboreal.
Evolution occurs differently in different species, some changes that were adapted by the diverged group of hominins were not adapted by chimpanzees and thus they did not develop the same characters as humans.
Hence, humans and chimpanzees share a common ancestor which was more arboreal as compared to the modern day human.
Want to see more full solutions like this?
- Design a grafting experiment to determine if limb mesoderm determines forelimb / hindlimb identity. Include the experiment, a control, and an interpretation in your answer.arrow_forwardThe Snapdragon is a popular garden flower that comes in a variety of colours, including red, yellow, and orange. The genotypes and associated phenotypes for some of these flowers are as follows: aabb: yellow AABB, AABb, AaBb, and AaBB: red AAbb and Aabb: orange aaBB: yellow aaBb: ? Based on this information, what would the phenotype of a Snapdragon with the genotype aaBb be and why? Question 21 options: orange because A is epistatic to B yellow because A is epistatic to B red because B is epistatic to A orange because B is epistatic to A red because A is epistatic to B yellow because B is epistatic to Aarrow_forwardA sample of blood was taken from the above individual and prepared for haemoglobin analysis. However, when water was added the cells did not lyse and looked normal in size and shape. The technician suspected that they had may have made an error in the protocol – what is the most likely explanation? The cell membranes are more resistant than normal. An isotonic solution had been added instead of water. A solution of 0.1 M NaCl had been added instead of water. Not enough water had been added to the red blood cell pellet. The man had sickle-cell anaemia.arrow_forward
- A sample of blood was taken from the above individual and prepared for haemoglobin analysis. However, when water was added the cells did not lyse and looked normal in size and shape. The technician suspected that they had may have made an error in the protocol – what is the most likely explanation? The cell membranes are more resistant than normal. An isotonic solution had been added instead of water. A solution of 0.1 M NaCl had been added instead of water. Not enough water had been added to the red blood cell pellet. The man had sickle-cell anaemia.arrow_forwardWith reference to their absorption spectra of the oxy haemoglobin intact line) and deoxyhemoglobin (broken line) shown in Figure 2 below, how would you best explain the reason why there are differences in the major peaks of the spectra? Figure 2. SPECTRA OF OXYGENATED AND DEOXYGENATED HAEMOGLOBIN OBTAINED WITH THE RECORDING SPECTROPHOTOMETER 1.4 Abs < 0.8 06 0.4 400 420 440 460 480 500 520 540 560 580 600 nm 1. The difference in the spectra is due to a pH change in the deoxy-haemoglobin due to uptake of CO2- 2. There is more oxygen-carrying plasma in the oxy-haemoglobin sample. 3. The change in Mr due to oxygen binding causes the oxy haemoglobin to have a higher absorbance peak. 4. Oxy-haemoglobin is contaminated by carbaminohemoglobin, and therefore has a higher absorbance peak 5. Oxy-haemoglobin absorbs more light of blue wavelengths and less of red wavelengths than deoxy-haemoglobinarrow_forwardWith reference to their absorption spectra of the oxy haemoglobin intact line) and deoxyhemoglobin (broken line) shown in Figure 2 below, how would you best explain the reason why there are differences in the major peaks of the spectra? Figure 2. SPECTRA OF OXYGENATED AND DEOXYGENATED HAEMOGLOBIN OBTAINED WITH THE RECORDING SPECTROPHOTOMETER 1.4 Abs < 0.8 06 0.4 400 420 440 460 480 500 520 540 560 580 600 nm 1. The difference in the spectra is due to a pH change in the deoxy-haemoglobin due to uptake of CO2- 2. There is more oxygen-carrying plasma in the oxy-haemoglobin sample. 3. The change in Mr due to oxygen binding causes the oxy haemoglobin to have a higher absorbance peak. 4. Oxy-haemoglobin is contaminated by carbaminohemoglobin, and therefore has a higher absorbance peak 5. Oxy-haemoglobin absorbs more light of blue wavelengths and less of red wavelengths than deoxy-haemoglobinarrow_forward
- Which ONE of the following is FALSE regarding haemoglobin? It has two alpha subunits and two beta subunits. The subunits are joined by disulphide bonds. Each subunit covalently binds a haem group. Conformational change in one subunit can be transmitted to another. There are many variant ("mutant") forms of haemoglobin that are not harmful.arrow_forwardWhich ONE of the following is FALSE regarding haemoglobin? It has two alpha subunits and two beta subunits. The subunits are joined by disulphide bonds. Each subunit covalently binds a haem group. Conformational change in one subunit can be transmitted to another. There are many variant ("mutant") forms of haemoglobin that are not harmful.arrow_forwardDuring a routine medical check up of a healthy man it was found that his haematocrit value was highly unusual – value of 60%. What one of the options below is the most likely reason? He will have a diet high in iron. He is likely to be suffering from anaemia. He lives at high altitude. He has recently recovered from an accident where he lost a lot of blood. He has a very large body size.arrow_forward
- Explain what age of culture is most likely to produce an endospore?arrow_forwardExplain why hot temperatures greater than 45 degrees celsius would not initiate the sporulation process in endospores?arrow_forwardEndospore stain: Consider tube 2 of the 7-day bacillus culture. After is was heated, it was incubated for 24 hours then refrigerated. Do you think the cloudiness in this tube is due mostly to vegetative cells or to endospores? Explain your reasoningarrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningHuman Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning
- Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeBiology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage LearningHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning





