Given below is a list of natural disturbances. A. Coral bleaching B. Rising sea levels C. Shifts in species distribution D. Lowering of sea levels E. Increase in glacial sheets Which one of the following combinations of disturbances can be attributed to global warming?
A, B and C
Global Warming and Natural Disturbances
Global warming refers to the long-term heating of Earth’s climate system observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere. This warming trend has significant impacts on the planet, leading to various natural disturbances.
Analyzing Disturbances Related to Global Warming
Let's examine each disturbance listed and determine its connection to global warming:
- A. Coral bleaching: This occurs when corals expel the algae (zooxanthellae) living in their tissues, causing them to turn completely white. Rising sea temperatures, a direct consequence of global warming, are a primary driver of coral bleaching events globally.
- B. Rising sea levels: Global warming causes sea levels to rise primarily through two mechanisms: thermal expansion of seawater as it warms and the melting of glaciers and ice sheets, which adds water to the oceans.
- C. Shifts in species distribution: As temperatures change and climate patterns are altered due to global warming, many plant and animal species are forced to move to new areas that are more suitable for their survival. This leads to shifts in their geographical distribution.
- D. Lowering of sea levels: Global warming generally causes sea levels to rise, not fall. While regional fluctuations can occur due to other factors, a general lowering of sea levels is not a characteristic disturbance caused by global warming on a global scale.
- E. Increase in glacial sheets: Global warming causes glaciers and ice sheets to melt at an accelerated rate, leading to a decrease in their size and volume, not an increase. An increase in glacial sheets would typically be associated with cooling periods.
Identifying the Correct Combination
Based on the analysis, the natural disturbances directly attributable to global warming from the given list are:
- Coral bleaching (A)
- Rising sea levels (B)
- Shifts in species distribution (C)
Disturbances D (Lowering of sea levels) and E (Increase in glacial sheets) are not typical or direct consequences of global warming; in fact, the opposite effects (rising sea levels and melting glaciers) are observed.
Therefore, the combination of disturbances that can be attributed to global warming is A, B, and C.
Important Questions from Applied Ecology
Which one of the following was recently reported to be the first mammal to have become extinct as a result of climate change?
The following information refers to ecological interactions.
Which one of the following options represents the correct match between column X and column Y?Column X Column X A Bass introduction into
aquatic systems(i) Bioaccumulation B Beavers (ii) Aposematism C Sea bird (such as puffins) (iii) Keystone species D Yellow and black stripes in a wasp (iv) Trophic cascades Which one of the options given below is NOT desirable when setting up nature reserves in the tropics?
A researcher captured 45 fish from a lake on day 1, tagged and released them back. On day 2 the researcher caught 50 fish out from the same lake, of which 15 were already tagged. Estimate the population size of fish in the lake with this information and pick the correct option.
In many sexually reproducing organisms females make mate choice decisions based on male display traits. Several models have been proposed to explain the evolution of exaggeration in male traits. Two of them have been given below in column P and their possible descriptions in column Q.
Column P
Column Q
A.
Runaway Se- lection (i)
Males exploit a pre-existing sensory bias in females. Females choosing such males have higher quality offspring. B.
Chase-away selection (ii)
Female choice for male trait occurs due to perceptual errors leading to poor quality offspring. Thus, females will evolve to run away from males with such traits. (iii)
Female choice for male trait results in a positive feedback loop favouring both, males with such trait and females that prefer them. (iv)
Males exploit pre-existing sensory bias in females. Females do not benefit by choosing such males, driving the evolution of females that discriminate against such males. Match the models to their appropriate description and choose the correct option.
