NSC Life Sciences Human Evolution: Read the extract below.

When a

Question

Read the extract below.

When a child is born, the umbilical cord and stem cells can be obtained from it. Many people think that the stem cells for treating human conditions should be obtained from umbilical cords, rather than from human embryos.

Recently, stem cells can also have been obtained from bone marrow. These stem cells are used to treat conditions such as heart disease and spinal injuries.

3.1.1 Explain WHY the characteristics of stem cells make them useful for treating some disorders.

3.1.2 Name THREE sources of stem cells mentioned in the extract.

3.1.3 Name ONE condition in the extract that can be treated with stem cells.

Read the extract below.

Samango and verret are two species of monkeys that occupy the same habitat. Researchers have recently discovered that a population of samango monkeys were able to interbreed with vervet monkeys to produce offspring. These offspring are fertile.

3.2.1 Define the term population.

3.2.2 Give ONE reason why samango and vervet monkeys are considered to be two different species.

3.2.3 List THREE mechanisms of reproductive isolation that are not mentioned above.

Scientists find evidence for human evolution by comparing humans to other hominids. The upper limbs of humans and African apes show similar characteristics. Researchers are looking for differences between the thumbs.

3.3.1 Explain the importance of the positioning of the thumbs for humans and African apes.

3.3.2 State ONE difference between the teeth of humans and African apes.

NSC

The diagram below represents one model of the evolution of some hominids.

3.4.1 Identify the type of diagram shown.

3.4.2 How many genera are represented by the diagram?

3.4.3 Name the species:

(a) Represented by X on the diagram
(b) That shares a common ancestor with Homo erectus

3.4.4 Which species of the genus Homo is the only one in existence today?

3.4.5 Name TWO forms of evidence that would have been used to support the information in the diagram.

3.4.6 The average cranial capacity of Homo sapiens is 1500 cm³ compared to 520 cm³ in Australopithecus africanus.

3.4.7 Explain the significance of the difference in cranial capacity.

Modern-day whales are aquatic mammals, spending their entire lives in the ocean. They are thought to have evolved from four-legged ancestors, as represented below.

3.5

SPECIES                     EXISTENCE ON EARTH                       CHARACTERISTICS
Pakicetus                     50 mya                                    Quadrupedal carnivore
Ambulocetus              48 mya                                   Flipper-like large feet and tail for swimming
Dorudon                    40 mya                                   Large flippers in front and very small hind limbs
Balaena (Blue whale) Present day                                Non-functioning valves in front

3.5.1 Which ancestor of whales most likely lived both in water and on land?

3.5.2 Give ONE reason for your answer to QUESTION 3.5.1.

3.5.3 Explain why Ambulocetus and Dorudon may be considered as transitional species in the evolution of whales.

3.5.4 Explain, according to Lamarck, why modern-day whales do not have legs.

Patients infected with the HI virus (HIV) are treated with antiretroviral drugs. When they miss their treatment, it can increase the chances (probability) of the virus developing resistance to the drug.

Scientists conducted an investigation to determine the effect of the number of missed treatments on the probability of the HI virus developing resistance to antiretroviral drugs.

The results are shown in the table below.

Number of missed treatments (in days)     Probability of the HI virus developing resistance to antiretroviral drugs (%)
2                                                               20
7                                                               30
14                                                             35
21                                                             40
37                                                             60

3.6 State the following for this investigation:

(a) the dependent variable
(b) the independent variable

3.6.2 Based on the results, state ONE conclusion for this investigation.

3.6.3 Describe the effect of the number of missed treatments on the probability of the HI virus developing resistance to antiretroviral drugs.

Read the extract below - NSC Life Sciences - Question 3 - 2022 - Paper 2

Worked Solution & Example Answer:Read the extract below - NSC Life Sciences - Question 3 - 2022 - Paper 2

Explain WHY the characteristics of stem cells make them useful for treating some disorders.

Name THREE sources of stem cells mentioned in the extract.

Name ONE condition in the extract that can be treated with stem cells.

Define the term population.

Give ONE reason why samango and vervet monkeys are considered to be two different species.

List THREE mechanisms of reproductive isolation that are not mentioned above.

Explain the importance of the positioning of the thumbs for humans and African apes.

State ONE difference between the teeth of humans and African apes.

Identify the type of diagram shown.

How many genera are represented by the diagram?

Name the species: (a) Represented by X on the diagram.

Name the species: (b) That shares a common ancestor with Homo erectus.

Which species of the genus Homo is the only one in existence today?

Name TWO forms of evidence that would have been used to support the information in the diagram.

Explain the significance of the difference in cranial capacity.

Which ancestor of whales most likely lived both in water and on land?

Give ONE reason for your answer to QUESTION 3.5.1.

Explain why Ambulocetus and Dorudon may be considered as transitional species in the evolution of whales.

Explain, according to Lamarck, why modern-day whales do not have legs.

the dependent variable.

the independent variable.

Based on the results, state ONE conclusion for this investigation.

Describe the effect of the number of missed treatments on the probability of the HI virus developing resistance to antiretroviral drugs.

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