← Back to 1. Evolution and the theme of Biology and Scientific Inquiry

📝 Overproduction and competition in evolution (12 MCQs)

📖 From Campbell Biology • 1. Evolution and the theme of Biology and Scientific Inquiry • 12 questions available

←Previous Topic:Heritable variation in natural selection📝 Overproduction and competition in evolutionAdaptation to environment natural selection:Next Topic→

What is Overproduction and competition in evolution?

Definition:
Overproduction and competition are key drivers in evolution, where organisms produce more offspring than the environment can support, leading to a struggle for limited resources such as food, water, and space, and only a fraction of offspring survive to reproduce, causing natural selection to favor individuals with advantageous traits, thereby shaping the evolution of species.

Working:
This works because populations have the potential to grow exponentially, as described by $N_t = N_0 \times 2^{t/g}$ , but resources are finite, so competition occurs, and the intensity of competition is influenced by the carrying capacity ( $K$ ) of the environment, with the logistic growth model $\frac{dN}{dt} = rN\left(\frac{K - N}{K}\right)$ , and individuals with superior adaptations are more likely to survive and reproduce, gradually altering the genetic makeup of the population.

Example:
A simple example is the competition among tree seedlings in a forest, where millions of seeds are produced, but only a few survive to maturity due to competition for light, water, and nutrients, and those that are taller or have larger leaves (better traits) are more likely to survive and reproduce, leading to a population of taller trees over generations.

Reason:
Overproduction and competition are fundamental to understanding natural selection, as they explain why some individuals survive while others do not, and this principle is essential for ecology, evolutionary biology, and resource management, as it predicts population dynamics and the evolution of traits like speed, size, and camouflage.

Easy

Medium

Hard

📝 All Overproduction and competition in evolution MCQs

Q1. A population of rabbits produces 200 offspring in one season, but the habitat can reliably support only 60 adults. Which conclusion best follows from these observations?

A.All offspring will eventually become adults because reproduction replaces mortality

B.Only 60 offspring can inherit favorable traits

C.Many offspring are unlikely to survive because limited resources create competition ✅

D.The population must immediately become genetically uniform

💡 Difficulty: easy | ✅ Correct: C

📖 Explanation: Producing more offspring than the environment can support means individuals must compete for limited food, shelter, water, and other resources. Consequently, many individuals will fail to survive or reproduce, creating unequal opportunities for future generations.

Q2. Why does producing more offspring than can normally survive become important when explaining differences in reproductive success?

A.It guarantees that every individual experiences exactly the same environment

B.It creates conditions in which limited resources can make survival and reproduction unequal ✅

C.It causes organisms to intentionally develop useful adaptations

D.It prevents inherited variation from occurring

💡 Difficulty: easy | ✅ Correct: B

📖 Explanation: Overproduction alone does not determine which individuals survive. However, when resources are limited, competition arises, and individuals possessing traits better suited to the prevailing conditions may have greater chances of surviving and reproducing.

Q3. Two bird populations occupy similar habitats. Population X produces 4 chicks per pair, whereas Population Y produces 10 chicks per pair. Food availability is limited in both habitats. What is the strongest prediction?

A.Population Y will necessarily increase ten times faster without mortality

B.Population X will always have greater genetic variation

C.Population Y is likely to experience stronger competition among offspring ✅

D.Population X cannot experience competition because it produces fewer offspring

💡 Difficulty: medium | ✅ Correct: C

📖 Explanation: When more offspring are produced under the same resource limitation, more individuals must compete for available resources. Therefore, Population Y is expected to experience stronger competition, although its final population size also depends on survival and reproduction.

Q4. A researcher observes that a plant produces 1,000 seeds, but only about 20 seedlings reach maturity. Which interpretation is most scientifically appropriate?

A.The plant intentionally sacrifices 980 seeds

B.The environment provides unlimited resources for only 20 seeds

C.High reproductive output is followed by substantial mortality before maturity ✅

D.The surviving seedlings must have identical inherited traits

💡 Difficulty: medium | ✅ Correct: C

📖 Explanation: The observation indicates that reproduction generates many more potential individuals than eventually reach reproductive age. Limited resources, environmental hazards, predation, disease, and competition can all contribute to mortality before maturity.

Q5. A drought reduces available grass by 50% while a deer population continues producing the same number of fawns. What is the most likely immediate ecological consequence?

A.Competition for food will decrease because fewer resources are available

B.Competition for food will increase because resource demand remains high relative to supply ✅

C.All fawns will acquire drought-resistant traits during development

D.Natural selection will stop because reproduction remains unchanged

💡 Difficulty: medium | ✅ Correct: B

📖 Explanation: If food availability falls while the number of consumers remains high, the ratio of demand to available resources increases. This intensifies competition, potentially lowering survival and reproductive success among individuals.

Q6. A population contains individuals with different feeding behaviors. During a period of food scarcity, individuals using one feeding strategy obtain food more efficiently and produce more surviving offspring. What process is most directly supported by this pattern?

A.Random mating without selection

B.Differential reproductive success associated with heritable variation ✅

C.Equal survival caused by environmental stability

D.Acquired inheritance caused solely by repeated behavior

💡 Difficulty: hard | ✅ Correct: B

📖 Explanation: The important sequence is variation, environmental limitation, differential access to resources, and unequal reproductive success. If the behavioral differences have a heritable component, individuals using the more effective strategy can contribute disproportionately to later generations.

Q7. A biologist claims, 'Because a species produces many offspring, its population must always grow rapidly.' Which evidence would most strongly challenge this claim?

A.The species has individuals with different body sizes

B.Most offspring die before reproducing because food and nesting sites are limited ✅

C.Adults reproduce at different times of the year

D.The species occupies more than one habitat

💡 Difficulty: medium | ✅ Correct: B

📖 Explanation: Population growth depends not only on the number of offspring produced but also on survival and reproduction. High mortality caused by limited resources can prevent a population from increasing despite substantial reproductive output.

Q8. Students propose that competition occurs only when organisms directly fight one another. A pond contains many tadpoles consuming the same limited algae, but they rarely contact each other. Which evaluation is best?

A.The students are correct because competition requires physical combat

B.The students are incorrect because competition can occur through shared depletion of limited resources ✅

C.The students are correct because algae are not living competitors

D.The students are incorrect because competition occurs only between different species

💡 Difficulty: easy | ✅ Correct: B

📖 Explanation: Competition does not require direct physical conflict. When individuals depend on the same limited resource, one individual's use can reduce availability for others, producing indirect competition even without physical encounters.

Q9. A population of insects produces approximately 1,000 eggs each generation. The graph shows that only 100 individuals survive to reproductive age, and the number remains near 100 across several generations. Which explanation best fits the pattern?

A.Egg production must be equal to adult population size

B.Environmental resistance and competition can offset high reproductive output ✅

C.The insects have stopped reproducing

D.Every egg has an equal probability of becoming an adult

💡 Difficulty: easy | ✅ Correct: B

📖 Explanation: The graph's stable adult number despite very high egg production suggests that mortality and resource limitation remove most potential individuals before reproduction. Thus, high fecundity does not necessarily produce sustained population growth.

Q10. Population A produces 500 offspring with 5% reaching reproductive age, while Population B produces 100 offspring with 40% reaching reproductive age. Which population produces more reproductive-age individuals under these conditions?

A.Population A, because it produces more offspring

B.Population B, because its survival percentage is higher

C.Both populations produce the same number ✅

D.There is insufficient information to compare them

💡 Difficulty: hard | ✅ Correct: C

📖 Explanation: Population A produces $500 \times 0.05 = 25$ reproductive-age individuals, while Population B produces $100 \times 0.40 = 40$ . Therefore, B produces more potential breeders despite starting with fewer offspring.

Q11. A researcher compares two habitats. In Habitat 1, 300 offspring are produced and 90 survive to reproduce. In Habitat 2, 600 offspring are produced but only 60 survive to reproduce. Which inference is strongest?

A.Greater offspring production always produces greater reproductive success

B.Habitat 2 has no competition because it produces more offspring

C.Higher survival proportion in Habitat 1 can produce greater reproductive contribution despite lower offspring production ✅

D.Habitat 1 must have fewer environmental limitations because it produces fewer offspring

💡 Difficulty: hard | ✅ Correct: C

📖 Explanation: Habitat 1 has a survival rate of $90/300=30\%$ , whereas Habitat 2 has $60/600=10\%$ . Thus, reproductive contribution depends on survival and reproduction, not simply on the number initially produced.

Q12. An ecologist models a population in which each pair produces 8 offspring. Food availability decreases as population density rises, and survival falls sharply above a density of 50 individuals. Which model prediction is most reasonable?

A.Population size should increase without limit because reproduction is fixed

B.Population size should fluctuate or stabilize as density-dependent competition increases ✅

C.Survival should increase automatically when density rises

D.Food availability should increase because more individuals are present

💡 Difficulty: easy | ✅ Correct: B

📖 Explanation: The model links increasing density with declining food availability and survival. As density rises, competition strengthens, reducing successful recruitment and creating a feedback that can slow population growth, stabilize the population, or generate fluctuations.

🔗 Related Topics (MCQs)

📝 The Study of Life Reveals Unifying Themes MCQs 📝 Hierarchical organization of life MCQs 📝 Reductionism in biology MCQs 📝 Emergent properties biology MCQs 📝 Systems biology MCQs

←Previous Topic:Heritable variation in natural selection📝 Overproduction and competition in evolutionAdaptation to environment natural selection:Next Topic→