Discuss sexual reproduction costs in wild populations
Qualify mate requirements, resource investment and timing.
Section B15.2 · Sexual reproduction
Mapped to the named 0654 section using teaching from the corresponding single-science course. A 0654-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade.
Before you begin
- Recall DNA, inherited characteristics, nuclei and the distinction between growth and reproduction.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
When does finding a separate mate become a relevant cost?
What you will learn
- Link a cost to the supplied reproductive route
- Avoid universal comparisons
Discuss sexual reproduction costs in wild populations
| Feature | Meaning |
|---|---|
| Availability | Compatible contributors may be scarce |
| Resources | Gametes and relevant reproductive structures |
| Timing | Depends on species and stages |
| Balance | Weigh variation benefits against supplied costs |
Link a cost to the supplied reproductive route
For a species that requires different adults to contribute gametes, finding a compatible mate can use time and energy. Low population density or separation can reduce the chance of successful reproduction. Link this cost to the supplied cross-fertilising route, rather than claiming that every sexual event requires two separate adults. Self-fertilisation is a relevant boundary example.
Producing gametes, reproductive structures and supporting offspring can require resources. Courtship, mating or attracting a pollinator may add costs in the relevant species. These are examples of possible investment, not stages that every animal and plant performs. An explanation should name the route and the resource involved instead of saying sexual reproduction is always expensive in exactly the same way.
Avoid universal comparisons
A sexual route may take longer or produce fewer successful offspring than a particular rapid copying route under favourable supplied conditions. That does not establish a universal ranking across all organisms. Generation time, gamete production, fertilisation success, development and survival vary. Compare actual records when provided and keep starting population size and observation period consistent.
A balanced wild-population discussion weighs these costs against inherited variation and possible survival under change. In a sparse cross-fertilising population, mate availability can matter greatly; in another setting, that limitation may be smaller. State the habitat and reproductive conditions before judging the tradeoff, and retain the distinction between a possible disadvantage and certain population failure.
Sources for this lesson
Pause and explain
Can one rapid copying example establish that all sexual reproduction is slower?
Worked example
A supplied cross-fertilising species is scattered across isolated habitat patches. Give one possible reproductive cost.
Show the worked solution
- Different adults must contribute.
- Finding a compatible partner may be difficult.
Answer Mate scarcity may reduce reproductive success or increase the time and energy spent finding a compatible mate.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Explain a possible mate-availability disadvantage for a sparse cross-fertilising population.
Give me a hint
Use the different-adult requirement.
Compare my reasoning
- A compatible contributor is needed.
- Low density can make encounters less likely or costly.
A sparse population may struggle to find compatible mates, reducing successful reproduction or increasing search costs.
Look for these in your work
- State the route requirement
- Link density to reproductive cost
Give a resource cost relevant to a supplied insect-pollinated plant and qualify it.
Give me a hint
Use the plant route rather than animal courtship.
Compare my reasoning
- Reproductive structures and gametes require resources.
- Pollinator attraction can be relevant to this route.
Producing flowers and gametes and supporting pollinator attraction can require resources in this plant route; those particular structures are not universal to all sexual organisms.
Look for these in your work
- Name a relevant cost
- Qualify the route
Give a balanced judgment for a cross-fertilising population facing both mate scarcity and environmental change.
Give me a hint
Weigh a cost and a possible variation benefit.
Compare my reasoning
- Mate scarcity can limit successful reproduction.
- Inherited variation may leave some offspring suited to change.
Mate scarcity can reduce reproduction, while inherited variation may improve survival under a particular change. The balance depends on the supplied habitat, contributors and stress.
Look for these in your work
- Address both sides
- Give a conditional conclusion
Common mistakes
- Applying mate-search costs to every self-fertilising event.
- Claiming a universal generation-time ranking.
What can you explain now?
Can one rapid copying example establish that all sexual reproduction is slower?
Compare with the explanation
No; species, conditions and stages vary
A single comparison is not universal proof.
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Make it stick
Explain two conditional costs and retain the self-fertilisation boundary.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.