A large forest area is fragmented into multiple smaller patches of different sizes. A researcher estimates the number of bird species in these forest fragments immediately following fragmentation, and then again 20 years later. The relationship between fragment size and species richness is shown in the graph for the two sampling events (immediately after fragmentation: closed circles and solid line; 20 years after fragmentation: open circles and dashed line). The best explanation for the differences in species richness with fragment size between the two sampling events is
A large forest area is fragmented into multiple smaller patches of different sizes. A researcher estimates the number of bird species in these forest fragments immediately following fragmentation, and then again 20 years later. The relationship between fragment size and species richness is shown in the graph for the two sampling events (immediately after fragmentation: closed circles and solid line; 20 years after fragmentation: open circles and dashed line). The best explanation for the differences in species richness with fragment size between the two sampling events is
Show Hint
- Allen's rule.
- K-selection.
- Extinction debt.
- Bergmann's rule.
The Correct Option is C
Solution and Explanation
Step 1: Analyzing the options.
- (A) Allen's rule: This rule states that animals in colder climates tend to have shorter appendages (ears, limbs) to conserve heat, which is not relevant to the question about species richness and habitat fragmentation.
- (B) K-selection: This refers to a reproductive strategy where species produce fewer offspring with higher parental investment. While it relates to species survival strategies, it is not the best explanation for changes in species richness following habitat fragmentation.
- (C) Extinction debt: This is the correct answer. It describes the phenomenon where species continue to exist in fragmented habitats even after the conditions for their survival have deteriorated, leading to eventual local extinctions.
- (D) Bergmann's rule: This rule states that animals in colder regions tend to have larger body sizes, which is unrelated to species richness in fragmented habitats.
Step 2: Conclusion.
The correct answer is (C) because extinction debt explains the observed differences in species richness between the two sampling events.
Final Answer: (C) Extinction debt.
Top GATE EY Ecology and Evolution Questions
- Which one of the following options denotes the time when the majority of animal phyla first appeared in the fossil record? (MYA = Million Years Ago)
- Which one of the following statements is true with respect to energy requirements of photosynthesis in C3 and C4 biochemical cycles?
- Moth caterpillars that mimic bird droppings are an example of which one of the following phenomena?
- Which one of the following processes is not likely to lead to the stable coexistence of two species at the same trophic level within an ecological community?
- A cross between a pure-bred plant with red flowers and a pure-bred plant with white flowers produced F1 generation with pink flowers. If the plants with pink flowers are selfed, what is the proportion of white : pink : red flowers expected in the next generation?
Top GATE EY Population ecology Questions
- Which one of the following sets of characteristics is most likely to cause population extinction via demographic stochasticity?
- A team of ecologists laid 100 plots of 50 m \(\times\) 50 m in a forest and counted the number of individuals of a tree species in each plot. They then calculated the mean and variance of the number of individuals per plot. If trees are randomly distributed, then which one of the following relationships between the variance and mean is expected?
- Which one of the following makes a species most vulnerable to extinction?
The probability of local extinction increases with body size when there is forest degradation, loss, and fragmentation. Consider the following hypotheses for the vulnerability of larger-bodied species:
(P) Larger-bodied species tend to have smaller population sizes.
(Q) Larger-bodied species require larger territories/home ranges.
(R) Larger-bodied species have higher absolute resource and energy requirements.Which one of the following options correctly lists all potential reasons for the vulnerability of larger-bodied species?
- Demographic stochasticity introduces random variation in population growth because
Top GATE EY Questions
- If '\(\rightarrow\)' denotes increasing order of intensity, then the meaning of the words [\textit{simmer} \(\rightarrow\) \textit{seethe} \(\rightarrow\) \textit{smolder}] is analogous to [\textit{break} \(\rightarrow\) \textit{raze} \(\rightarrow\) \_\_\_\_\_\_]. Which one of the given options is appropriate to fill the blank?
- In a locality, the houses are numbered in the following way:The house-numbers on one side of a road are consecutive odd integers starting from \(301\), while the house-numbers on the other side of the road are consecutive even numbers starting from \(302\). The total number of houses is the same on both sides of the road. If the difference of the sum of the house-numbers between the two sides of the road is \(27\), then the number of houses on each side of the road is:
- For positive integers \( p \) and \( q \), with \( \frac{p}{q} \neq 1 \), \( \left( \frac{p}{q} \right)^q = p^{q-1 \). Then, which of the following is true?}
- Which one of the given options is a possible value of \(x\) in the following sequence? 3, 7, 15, x, 63, 127, 255
- On a given day, how many times will the second-hand and the minute-hand of a clock cross each other during the clock time 12:05:00 hours to 12:55:00 hours?