[Maximum number: 3]

Several studies have been undertaken to determine whether there is an evolutionary explanation for menopause, the time when reproductive capacity stops in women. Two contemporary hunter-gatherer societies were studied. The graph shows what percentage of women survive to each of the ages given.

(a)

Foraging (food-getting) requires skill gained with experience and age. The Grandmother Hypothesis suggests that after menopause, women who are skilled at foraging provide greater survivorship success to the offspring of their daughters. The graph shows the foraging patterns of women in three groups.

Group I Have reached puberty, but have not begun child-bearing
Group II Are pregnant and/or have young children
Group III Have passed child-bearing age and have no children younger than 15 years old

Calculate the difference in the amount of time spent foraging by the most skilled women in groups I and III.

[ 1 ]

(b)

Evaluate the data in terms of the Grandmother Hypothesis.

[ 2 ]

[Maximum number: 3]

The drawing shows part of a Thunbergia grandiflora plant. It has been widely cultivated as an ornamental garden plant.

(a)

After fertilization, seeds of T. grandiflora form in a small pod. If you were provided with Petri dishes, absorbent cotton balls and seeds, suggest how one variable affecting germination of these seeds could be investigated.

[ 3 ]

[Maximum number: 1]

Concerns have been raised about the effect of rising pollution levels on sperm production in men. To investigate the possible effects of pollution on spermatogenesis, sperm samples from men of similar ages were collected in Kolkata in the 1980s and 2000s. The box plot represents the mean and range of sperm counts in the 1980s and 2000s.

(a)

The light micrograph shows a cross section of seminiferous tubules.

[ 1 ]

(i)

Identify the type of cell labelled Z .

[ 1 ]

[Maximum number: 2]

Hemophilia is a sex-linked disease that affected some members of royal families in Europe during the 19th and 20th centuries.

(a)

Explain the mechanism that prevents polyspermy during fertilization.

[ 2 ]

[Maximum number: 1]

Which diagram(s) represent(s) processes used in asexual reproduction?

I only

I and II only

II only

I, II and III

[Maximum number: 1]

The micrograph shows a cross section of a lily (Lilium longiflorum) anther.

What can be found in X ?

Haploid nuclei produced by meiosis

Diploid nuclei produced by fertilization

Haploid nuclei produced by mitosis

Diploid nuclei produced by pollination

[Maximum number: 2]

This redwood tree (Sequoia sempervirens) was blown over in 1936, but five side branches formed new roots and are now separate trees.

Three of the new trees formed from side branches of the original tree

(a)

If the genomes of the five new trees were sequenced, predict with a reason how similar they would be to each other.

[ 2 ]

[Maximum number: 1]

What term describes genetically identical organisms derived from a single parent?

Species

Clone

Family

Twins

[Maximum number: 4]

A broad bean is the seed of a species, Vicia faba, in the Fabaceae, a family of flowering plants. This family contains many species that are used as sources of food.

(a)

On the diagram, label the testa and the radicle.

[ 2 ]

(b)

An experiment was done to test the hypothesis that temperature affects the rate of germination of the broad bean. Outline two factors apart from temperature that should be controlled in this experiment.

[ 2 ]

[Maximum number: 1]

Amniocentesis and chorionic villus sampling (CVS) are used to test for fetal abnormalities. Which statement is a valid comparison between the two tests?

CVS is performed later in pregnancy but has more risk of miscarriage than amniocentesis.

Amniocentesis is performed earlier in pregnancy but has more risk of miscarriage than CVS.

CVS is performed earlier in pregnancy but has more risk of miscarriage than amniocentesis.

Amniocentesis is performed later in pregnancy but has more risk of miscarriage than CVS.