3 A sycamore tree is a producer for many food chains in a forest ecosystem. (a) Explain what is meant by: (i) a producer … … [1] (ii) a food chain. … … [1] (b) The diagrams show a pyramid of numbers and a pyramid of biomass for a sycamore tree. birds of prey birds insects tree pyramid of numbers pyramid of biomass Explain the different shapes of the two pyramids. … … … … … … … [4] (c) Sycamore trees produce flowers that are insect-pollinated. Suggest two features of flowers which adapt them for insect-pollination. 1 … 2 … [2] (d) State the type of cell division that produces pollen grains. … [1] [Total: 9]

3(a)(i) photosynthesis / autotrophic / making own organic nutrients ; 1 3(a)(ii) flow / transfer + energy / food ; 1 3(b) any four from: biomass tree has large mass so long rectangle / correct reference to relative masses at two trophic levels ; biomass declines as trophic level increases ; numbers there is only one tree so a short rectangle for numbers / correct reference to relative numbers at two trophic levels ; both or either after producer both pyramids in shape ; energy is lost (to the environment) ; as heat / thermal energy ; from respiration ; 4 3(c) any two from: large / colourful + petals / sepals ; nectaries / nectar ; scent ; anthers / stigma + inside petals / short / sticky stigma ; markings / nectar guides / petals modified with insect landing site ; pollen rough / sticky ; 2 3(d) meiosis ; 1

3 The diagram shows an elm tree. (a) Elm trees may be infected by a fungus that causes a disease. State two characteristics of a fungus. 1 … 2 … [2] (b) The fungus moves through an infected tree inside the xylem vessels. The tree responds to stop the movement of the fungus by producing substances that block the xylem vessels. This causes the leaves of the tree to wilt and to become yellow. Explain how the response of the tree to infection leads to these symptoms of disease. … … … … … … … … … … [5] (c) An insect called the elm bark beetle is the vector of this disease. Describe what is meant by the term vector. … … … … [2] (d) Elm trees can reproduce when the roots from one parent tree spread out near the surface of the soil. This is shown in the diagram below. roots of parent tree grow stems called suckers each sucker forms a new tree (i) Name the type of reproduction shown in the diagram. … [1] (ii) Suggest why this type of reproduction makes it difficult to control the spread of the disease caused by the fungus. … … … … … … [3] [Total: 13]

3(a) 1 hyphae / mycelium ; 2 saprotrophic / saprophytic / feeds on dead matter AW / decomposer ; 3 spores ; 4 cell wall + chitin ; 5 more than one nucleus / multinucleate ; 2 3(b) 1 less / no + water transported / water absorbed / transpiration ; 2 water loss greater than water uptake ; 3 less + water in cells ; 4 flaccid / loss of turgor / plasmolysed ; 5 magnesium / Mg ; 6 less / no + chlorophyll ; 5 3(c) 1 transfer / carries / spreads AW + pathogen / fungus / parasite ; 2 one organism AW to another ; 3 not itself + affected / infected ; 2 3(d)(i) asexual ; 1 3(d)(ii) 1 close together ; 2 connected AW ; 3 genetically identical / all genetically susceptible / clones ; 3

4 A study investigated the probability of pregnancy resulting from sexual intercourse on specific days of the menstrual cycle. The graph shows the results of this study. 5 0 10 20 30 40 50 4 3 days before ovulation percentage probability of pregnancy 2 1 ovulation (a) (i) The study shows a probability of 20% that sexual intercourse three days before ovulation will result in pregnancy. State how many times more likely pregnancy is if sexual intercourse takes place two days later. … [1] (ii) Explain the role of named hormones in the menstrual cycle during the days investigated by this study. … … … … … … … … [5] (b) The diagram shows a fetus developing in the uterus of a pregnant female human. structure X Name structure X and describe the functions of this structure. name … functions … … … … … [3] [Total: 9]

4(a)(i) 2 / twice as likely / doubles ; 1 4(a)(ii) FSH ; (only if FSH stated) growth / maturation + of follicle ; (only if FSH stated) in ovary ; oestrogen ; (only if oestrogen stated) repair AW of uterus + wall / lining ; LH ; (only if LH stated) ovulation AW ; 5 4(b) placenta ; 1 any two from … diffusion ; oxygen / glucose / antibodies + from mother / to fetus AW ; carbon dioxide / urea + from fetus AW / to mother ; from blood + to blood ; produces progesterone ; 2

6 The diagram shows the human life cycle. The components of the diagram are not drawn to the same scale. The diagram shows: • cells L, M and N • two types of cell division, K and O. N K L fertilisation O M (a) L and M are both the same type of cell. Name this type of cell. … [1] (b) Outline differences between the nucleus of cell M and the nucleus of cell N. … … … … [3] (c) Name and compare the types of cell division K and O. … … … … … … … … … … [6] [Total: 10]

6(a) gamete(s) ; 1 Ig sex cell 6(b) 1 M + haploid / 23 chromosomes ; 2 M + only X chromosome ; 3 N + diploid / 46 chromosomes / 23 pairs of chromosomes ; 4 N + either XX or XY chromosomes ; 3 6(c) 1 K + meiosis ; 1 2 O + mitosis ; 1 (marking points 3–8 must be linked to meiosis or to K if meiosis not named) 3 reduction division ; 4 chromosome + number halved / 46 to 23 ; 5 diploid + to haploid ; 6 four daughter AW cells ; 7 genetically different ; 8 takes place in + testes / ovaries / gonads ; (marking points 9–13 must be linked to mitosis or to O if mitosis not named) 9 chromosome + number maintained / 46 to 46 ; 10 diploid + to diploid ; 11 genetically identical / clones ; 12 growth ; 13 two daughter AW cells ; 4

Cambridge O Level Biology · 5090

O-Level Biology (5090) Development of organisms and continuity of life past paper questions

Revise O-Level Biology (5090) — Development of organisms and continuity of life with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

94 free questions from 2017–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Development of organisms and continuity of life in O-Level Biology 5090 exams, 2020–2025

Across 2020–2025, Development of organisms and continuity of life accounted for 117 questions worth 459 marks in Cambridge O Level Biology (5090) papers.

By year
Year	Questions	Marks
2020	19	82
2021	15	88
2022	22	99
2023	22	72
2024	23	59
2025	16	59

Most-tested subtopics

16.3 Sexual reproduction in plants182 marks
16.2 Asexual and sexual reproduction110 marks
16.4 Sexual reproduction in humans80 marks

Appears in

Paper 1 · 84 qs
Paper 2 · 29 qs
Paper 3 · 3 qs
Paper 4 · 1 q

All most-tested Biology topics

2021 May/Jun · Paper 2 · Q3 · 9 marks
Marking scheme
Get Steven’s plain-English explanation
2021 May/Jun · Paper 2 · Q3 · 13 marks
Marking scheme
Get Steven’s plain-English explanation
2021 Oct/Nov · Paper 2 · Q4 · 9 marks
Marking scheme
Get Steven’s plain-English explanation
2021 May/Jun · Paper 2 · Q6 · 10 marks
Marking scheme
Get Steven’s plain-English explanation
2021 May/Jun · Paper 1 · Q33 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q33
Answer: C
Get Steven’s plain-English explanation