Biology • Year 12 • Module 5 • Lesson 1
Reproduction and Continuity of Species
Lock in the core vocabulary, the sexual-vs-asexual comparison, and the role of DNA transfer in keeping a species going across generations.
1. Label the continuity-of-species diagram
The diagram below contrasts the two reproductive strategies introduced in this lesson and tracks what happens to genetic information across one generation. Write the missing labels into boxes A–H. Each label is drawn from the lesson's Key Terms or from Cards 1–4. 8 marks
- A — strategy name (___ reproduction) _______________________
- B — number of parents required _______________________
- C — genetic variation in offspring (high/low?) _______________________
- D — resilience to environmental change _______________________
- E — strategy name (___ reproduction) _______________________
- F — process that fuses gametes _______________________
- G — genetic variation in offspring (high/low?) _______________________
- H — speed of population increase _______________________
| Box | Your label |
|---|---|
| A | |
| B | |
| C | |
| D | |
| E | |
| F | |
| G | |
| H |
2. Term–definition match
The ten definitions below are shuffled. In the right-hand column write the matching term from this list: reproduction, continuity of species, sexual reproduction, asexual reproduction, variation, gamete, clone, binary fission, vegetative propagation, hereditary information. 10 marks
| # | Definition (shuffled) | Matching term |
|---|---|---|
| 2.1 | The biological process by which organisms produce offspring and transfer DNA to the next generation. | |
| 2.2 | Reproduction from one parent without fusion of gametes; offspring are usually genetically near-identical to the parent. | |
| 2.3 | The ongoing existence of a species across generations through successful reproduction and inheritance of DNA. | |
| 2.4 | An asexual offspring that is genetically near-identical to its parent. | |
| 2.5 | Reproduction involving the fusion of gametes, usually from two parents, producing genetically varied offspring. | |
| 2.6 | Genetic information passed from parent to offspring; what reproduction transfers. | |
| 2.7 | A haploid sex cell, such as a sperm or egg, that fuses during fertilisation. | |
| 2.8 | Differences in characteristics between individuals in a population, often linked to differences in alleles. | |
| 2.9 | An asexual mechanism in bacteria where one cell divides into two genetically near-identical daughter cells. | |
| 2.10 | An asexual mechanism in plants where new individuals grow from a parent's stems, roots or leaves (e.g. strawberry runners). |
3. True or false — with correction
For each statement, circle T or F. If the statement is false, write the corrected version. 8 marks (1 for T/F, 1 for the correction where needed)
3.1 Continuity of a species depends on individual organisms living forever. T / F
3.2 Asexual reproduction produces offspring with greater routine genetic variation than sexual reproduction. T / F
3.3 Reproduction is the mechanism by which hereditary information is transferred from parent to offspring. T / F
3.4 Sexual reproduction is always the best reproductive strategy regardless of environment. T / F
4. Function recall
Answer each in 1–2 sentences using precise terms from the lesson. 10 marks (2 each)
4.1 What is the function of reproduction at the level of a whole species (not the individual)?
4.2 What is the function of transferring hereditary information from parents to offspring?
4.3 What is the function of gamete fusion in sexual reproduction?
4.4 What is the function of genetic variation in a population whose environment is changing?
4.5 What is the function of asexual reproduction for an organism that has just colonised a new but stable habitat?
5. Build a concept map
Draw labelled arrows between the five terms below to show how they connect. Each arrow must carry a linking phrase (e.g. "transfers", "produces", "supports"). Aim for at least 5 labelled arrows. 5 marks
Supplied terms: reproduction · hereditary information (DNA) · offspring · genetic variation · continuity of species.
Q1 — Labelled diagram
A: asexual (reproduction). B: one parent. C: low (offspring are genetically near-identical / clones, apart from mutation). D: often lower / reduced (genetic uniformity reduces resilience to environmental change such as disease). E: sexual (reproduction). F: fertilisation (fusion of gametes to form a zygote). G: high (offspring receive new combinations of alleles from two parents). H: usually slower (mate finding and gamete production take time and energy). Example of asexual reproduction from the lesson: Cavendish banana propagation / bacterial binary fission / yeast budding / strawberry runners.
Q2 — Term–definition matches
2.1 reproduction • 2.2 asexual reproduction • 2.3 continuity of species • 2.4 clone • 2.5 sexual reproduction • 2.6 hereditary information • 2.7 gamete • 2.8 variation • 2.9 binary fission • 2.10 vegetative propagation.
Q3 — True / false with correction
3.1 False. Correction: continuity of a species depends on successful reproduction and the transfer of DNA across generations, not on the immortality of any individual.
3.2 False. Correction: asexual reproduction produces offspring with much less routine variation — sexual reproduction routinely produces greater variation through gamete fusion and reshuffling of alleles.
3.3 True.
3.4 False. Correction: neither strategy is universally best — under stable conditions asexual reproduction can be more effective, while sexual reproduction tends to be more advantageous under changing conditions because it generates more variation.
Q4.1 — Function of reproduction (species level)
At the species level, reproduction's function is to produce a new generation of offspring and to transfer hereditary information to them, so that the species persists even though individual organisms die. It is the mechanism that prevents extinction one generation at a time.
Q4.2 — Function of transferring hereditary information
Transferring DNA from parents to offspring ensures that the next generation inherits the genes needed to develop into functional organisms of the same species. Without this transfer there is no continuity — offspring would lack the genetic instructions that define the species.
Q4.3 — Function of gamete fusion
Fusion of two haploid gametes combines genetic information from two parents into a single diploid zygote. This both restores the species' normal chromosome number and produces a new allele combination, which is the source of routine genetic variation in sexual reproduction.
Q4.4 — Function of genetic variation in a changing environment
Genetic variation means individuals carry different allele combinations. When the environment changes (e.g. a new pathogen, drought, temperature shift), at least some individuals are more likely to possess allele combinations suited to the new conditions, so the population is less likely to be wiped out as a whole — increasing the chance of continuity.
Q4.5 — Function of asexual reproduction in a new, stable habitat
Asexual reproduction lets one well-adapted individual rapidly produce many offspring without needing a mate. In a stable habitat where one genotype already works well, this fills the habitat quickly and efficiently — the trade-off (low variation) does not matter as much when conditions are not changing.
Q5 — Sample concept map
A correct map should include arrows such as:
- reproduction — produces → offspring
- reproduction — transfers → hereditary information (DNA)
- hereditary information (DNA) — is inherited by → offspring
- offspring — across generations supports → continuity of species
- reproduction (sexual) — generates → genetic variation
- genetic variation — improves resilience and so supports → continuity of species
Any biologically valid linking phrases are accepted. Award full marks for at least 5 correctly labelled arrows that respect causal direction.