Ecological Principles MCQ Quiz - Objective Question with Answer for Ecological Principles - Download Free PDF

The correct answer is Option 3 and Option 4

Explanation:

Mutualism is a type of symbiotic relationship where both organisms involved benefit from the association.

1. Human - Mycobacterium tuberculosis:

• Mycobacterium tuberculosis is the bacterium that causes tuberculosis (TB), a severe infectious disease in humans.
• In this relationship, Mycobacterium tuberculosis benefits by infecting and multiplying within the human host, but the human host is harmed, often severely.
• This is a parasitic relationship, not mutualism.

2. Dog - Rabies lyssavirus:

• Rabies lyssavirus is the virus that causes rabies, a fatal neurological disease in dogs and other mammals.
• The virus benefits by replicating within the host and being transmitted, while the dog is severely harmed, leading to death.
• This is a parasitic relationship, not mutualism

3. Human - Lactobacillus plantarum:

• Lactobacillus plantarum is a species of lactic acid bacteria commonly found in the human gastrointestinal tract and in fermented foods.
• In the human gut, Lactobacillus species contribute to digestion, produce beneficial compounds (like lactic acid, which can inhibit the growth of harmful bacteria), synthesize some vitamins, and help maintain gut health. The human host provides a stable environment and nutrients for the bacteria.
• This is a classic example of mutualism, as both the human host and the bacterium derive benefits.

4. Cow - Ruminococcus albus:

• Cows are ruminant animals that consume large amounts of plant material, which contains cellulose (a complex carbohydrate). Cows themselves lack the enzymes (cellulases) to digest cellulose.
• Ruminococcus albus is an anaerobic bacterium that lives in the rumen of cows. It produces cellulase enzymes that break down cellulose into simpler sugars and volatile fatty acids, which the cow can then absorb and use as a primary energy source. In return, the cow's rumen provides a stable, anaerobic environment and a continuous supply of plant material for the bacteria.
• This is a prime example of mutualism, as the cow benefits from nutrient extraction from cellulose, and the bacterium thrives in a nutrient-rich habitat.

The correct answer is Hybrid sterility

Explanation:

• Speciation refers to the process by which new species arise. It often involves isolating mechanisms that prevent gene flow between populations.
• Isolating mechanisms can be categorized into two main types: pre-zygotic and post-zygotic.
• Post-zygotic isolating mechanisms occur after fertilization and prevent the resulting hybrid from becoming a viable or fertile adult.
• Hybrid sterility is an example of a post-zygotic isolating mechanism where the hybrid offspring is infertile, preventing gene flow between species.
  • Hybrid sterility occurs when the offspring of two different species are sterile and unable to reproduce.
  • This is caused by genetic incompatibilities, such as differences in chromosome number or structure, resulting in improper formation of gametes.
  • A classic example is the mule, a hybrid of a horse and a donkey. Mules are sterile because of mismatches in chromosome pairing during gamete formation.
  • Hybrid sterility ensures that even if two species can mate and produce offspring, the gene flow between them is blocked, contributing to speciation.

Other options:

• Behavioral isolation:
  • This is a pre-zygotic isolating mechanism, not post-zygotic. It occurs when differences in mating behaviors or courtship rituals prevent species from interbreeding.
  • For instance, certain bird species may have unique songs or dances that are recognized only by members of their own species.
• Fertilization failure:
  • This is also a pre-zygotic isolating mechanism. It occurs when sperm and egg fail to unite due to incompatibilities such as mismatched proteins on their surfaces.
  • For example, marine organisms like corals and sea urchins often release gametes into the water, but only gametes of the same species can successfully fertilize each other.
• Seasonal isolation:
  • Another pre-zygotic isolating mechanism. It occurs when species reproduce at different times of the year or season, preventing interbreeding. An example includes plants that flower during different months, ensuring that pollen exchange is limited to members of the same species.

The correct answer is Cuckoo

Explanation:

• A "brood parasite" is an organism that relies on others to raise its young. Instead of building their own nests or caring for their offspring, brood parasites lay their eggs in the nests of other species. The host species then incubates the eggs and raises the young as their own.
• The most well-known example of a brood parasite is the cuckoo bird, which has evolved various strategies to ensure the survival of its offspring, often at the expense of the host's own chicks.
  • Cuckoos lay their eggs in the nests of other bird species, such as warblers or robins.
  • The cuckoo egg often mimics the appearance of the host's eggs, reducing the chance of detection and rejection by the host bird.
  • Once the cuckoo chick hatches, it may push the host's eggs or chicks out of the nest to monopolize the food brought by the host parents.
  • This behavior ensures the survival of the cuckoo chick, while the host birds unknowingly invest their resources in raising an unrelated offspring.

Other options:

• Pigeon: Pigeons are not brood parasites. They build their own nests and raise their young by feeding them crop milk, a nutrient-rich secretion produced by both male and female pigeons.
• Sparrow: Sparrows are not brood parasites. They are small, social birds that build their own nests and actively care for their offspring by feeding them a diet of seeds and insects.
• Goose: Geese are not brood parasites. They are waterfowl that lay their eggs in nests they construct themselves, often near water bodies. Both parents may play a role in protecting and raising the young.

The correct answer is P,Q and S

Explanation:

Rabbits introduced into an isolated grassland for the first time would experience population dynamics that generally follow either exponential or logistic growth patterns, though environmental factors can cause fluctuations. 

• P (Fluctuating Growth): This curve shows the rabbit population initially increasing, then decreasing, then increasing again, but with significant oscillations. This pattern is theoretically possible in a real-world scenario. While initial growth might be exponential, as resources become limited or predator populations increase (if predators are also introduced or already present), the rabbit population can overshoot the carrying capacity, leading to a decline, followed by a recovery as resources replenish or predator numbers decrease, creating these fluctuations around the carrying capacity.
• Q (Sigmoidal/Logistic Growth): This curve represents a classic logistic growth pattern. The population initially grows slowly (lag phase), then rapidly (log or exponential phase), and finally slows down and stabilizes as it approaches the carrying capacity (K) of the environment. This is a very common and theoretically possible growth curve for a new population introduced into a limited environment.
• R (Linear/Constant Growth): This curve depicts a population growing at a constant rate over time, resulting in a straight line. This is highly unlikely and theoretically not possible for a biological population. Population growth is typically proportional to the current population size (exponential) or limited by resources (logistic), not constant.
• S (Oscillating with Declining Amplitude): This curve shows initial growth followed by oscillations that gradually decrease in amplitude, eventually stabilizing. This is a more refined representation of logistic growth with overshooting and damped oscillations. It's theoretically possible and often observed in populations that initially overshoot their carrying capacity but then gradually settle towards it.

The correct answer is Predatory spiders.

Key Points

• Predatory spiders have a high assimilation efficiency (over 90%) due to their ability to effectively convert prey biomass into their own biomass.
• Spiders are efficient predators, consuming prey with minimal energy wastage, which allows them to achieve high energy transfer rates.
• They utilize external digestion by secreting digestive enzymes, which enhances nutrient assimilation.
• Predatory spiders are important in regulating prey populations and maintaining ecological balance.

Additional Information

• Secondary carnivores: These are organisms that feed on primary carnivores. While they are efficient predators, their assimilation efficiency is generally lower than predatory spiders as they consume organisms with more complex energy pathways.
• Herbivores: Herbivores feed on plant material, which is difficult to digest due to the presence of cellulose and lignin. Their assimilation efficiency is typically lower (around 20–50%) compared to carnivores.
• Social insects: Social insects like ants and bees have specialized roles within colonies. Their efficiency depends on their dietary habits, but they generally do not achieve assimilation efficiencies as high as predatory spiders.

The correct answer is Dolphins.

Key Points 

• The Gangetic river dolphin is India's national aquatic animal and is popularly known as ‘Susu’.
• Dolphins are one of the oldest creatures in the world along with some species of turtles, crocodiles, and sharks.
  • The Ganges river dolphin was officially discovered in 1801.
  • Ganges river dolphins once lived in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India, and Bangladesh. But the species is extinct from most of its early distribution ranges.
  • The Ganges river dolphin can only live in freshwater and is essentially blind.
  • They hunt by emitting ultrasonic sounds, which bounce off of fish and other prey, enabling them to “see” an image in their mind.
  • They are frequently found alone or in small groups, and generally a mother and calf travel together.
  • Calves are chocolate brown at birth and then have grey-brown smooth, hairless skin as adults.
  • Females are larger than males and give birth once every two to three years to only one calf.
• It is among the four freshwater dolphins in the world- the other three are:
  • The ‘Baiji’ is now likely extinct from the Yangtze River in China.
  • The ‘Bhutan’ of the Indus in Pakistan
  • The ‘Boto’ of the Amazon River in Latin America. 

Important Points 

• Vikramshila Gangetic Dolphin Sanctuary:
  • It is situated in the Bhagalpur district of Bihar, India.
  • The sanctuary is a 50 km stretch of the Ganges River from Sultanganj to Kahalgaon.
  • It was designated as a protected area for the endangered Gangetic dolphins in 1991.

Concept:

• Productivity is defined as the rate of biomass production per unit area.
• Primary productivity is the rate of biomass production per unit area by the primary producer. 
• The producer is any organism that produces food through photosynthesis. 
• The producer is the first level of the ecosystem that provides energy to all of the consumers in the ecosystem.
• The total amount of energy fixed by the producer through photosynthesis is referred to as gross primary productively (GPP).
• While the amount of energy that remains after respiration loss in the producer is referred to as Net primary productivity (NPP).
•  Hence, NPP = GPP - Respiration
• So, NPP is the actual biomass that is available for consumption by the primary consumers (heterotrophic organisms).
• The rate of production of new biomass by the primary consumers (heterotrophic organisms) is called secondary productivity.

Important Points

• Tropical rainforests, swamps and marshes, and algae beds and reefs are ecosystems with the highest Net primary productivity. 
• While open ocean and desert ecosystems have the lowest NPP. 
• It can be seen in the second graph where NPP is given in g/m²/yr. This graph demonstrates the average net primary productivity of different ecosystems.
• The third graph demonstrates the productivity in relation to the amount of area that type of ecosystem occupies on the Earth. It shows the annual world net primary production of the different ecosystems on the earth. 
• Open ocean has the largest percentage of world's annual NPP. i.e., the open ocean contributes 24.4% of the world's net primary productivity. This is because around 70% of the Earth’s surface is occupied by the ocean.
• The second highest world annual NPP is of  tropical rain forest (22%), followed by swamps and marshes (2.3%) and lastly algae beds and reefs (0.9%)
• So, the correct order of the ecosystem in increasing order of NPP is - algae beds and reefs (0.9%), swamps and marshes (2.3%), tropical rain forests (22%) and open oceans (24.4%). 

Hence, the correct answer is option 4.

The correct answer is Option 2 i.e. 14 130 56 200

Key Points

• The efficiency with which energy is transferred from one trophic level to the next is called ecological efficiency. 
• Energy transfer in the ecosystem is not efficient, as only almost 10% of energy is transferred to the next trophic level, while 90% of the energy is lost to the environment. 
• Due to non-predation death, egestion, and cellular respiration, a  notable amount (almost 80 -90 %)  of energy is lost to the environment.
• Ecological efficiency included various related efficiency, which is as follow: 

1. Exploitation efficiency/ consumption efficiency(CE)
   • It is defined as the percentage of food available at one trophic level that is consumed (ingested) by the consumers. at one trophic level. 
   • \(CE = \frac {I_n}{p_{n-1}} \times 100\)
2. Assimilation efficiency (AE)
   • It is defined as the percentage of food assimilated across the gut wall and becomes incorporated into growth.
   • \(AE = \frac {A_n}{I_n} \times 100\)
3. Net production efficiency (PE)
   • It is defined as the percentage of assimilated energy \((A_n)\) that is converted into new biomass. 
   • \(PE = \frac{P_n}{A_n} \times 100\)

Explanation:

• Given : Pn - 1 = 1000 kcal, I/Pn - 1 = 20%, A/I = 35% and Pn/A = 20%
• First we will find the amount ingested i.e., I.
• \(\begin{equation} \begin{split} \frac{I}{Pn-1} & = 20\% \\ \frac{I}{1000kcal} & = \frac{20}{100} \\ I & = \frac{20}{100} \times 1000 \\ I& = 200 \space kcal \end{split} \end{equation} \)
• Now, we will find the amount assimilated
•  \(\begin{equation} \begin{split} \frac{A}{I} & = 35\% \\ \frac{A}{200\space kcal} & = \frac{35}{100} \\ A & = \frac{35}{100} \times 200 \\ A& = 70 \space kcal \end{split} \end{equation} \)
• Ingestion =  Assimilated + Non-assimilated 
• \(\begin {equation} \begin {split} NA &= I-A \\ NA &= 200 -70\\ NA &= 130 \space kcal \end {split} \end {equation} \)
• Now, we will find the amount of biomass produced at the trophic level. 
• \(\begin{equation} \begin{split} \frac{Pn}{A} & = 20\% \\ \frac{Pn}{70\space kcal} & = \frac{20}{100} \\ Pn & = \frac{20}{100} \times 70 \\ Pn& = 14 \space kcal \end{split} \end{equation}\)
• Lastly, we will find the amount of biomass lost in the respiration 
• The amount of biomass assimilated is used for carrying out respiration and also passed on to the next trophic level. 
• \(\begin{equation} \begin{split} A& = R + Pn \\ R & = A-Pn \\ R & = 70-14 \\ R& = 56 \space kcal \end{split} \end{equation}\)
• So, Pn = 14, NA = 130, R = 56 and I = 200

Hence, the correct answer is Option 2.

The correct answer is 622.

Concept:

The mark-recapture method to estimate the population size of grasshoppers. This method is based on the assumption that the ratio of marked to total individuals in the sample is the same as the ratio of marked to total individuals in the entire population.

The population size (N) can be estimated using the Lincoln-Petersen formula for each day:

𝑁 = (𝑀×𝐶)/𝑅
N=RM×C​

Where:M M" id="MathJax-Element-43-Frame" role="presentation" style="position: relative;" tabindex="0">​

• M is the total number of marked individuals in the population (before the recapture on that day),
• C is the total number of individuals captured on the day,
• R is the number of marked individuals in the recaptured sample.

Solution:

Day 2:

• M=40 (from day 1, all marked)
• C=60 (recaptured grasshoppers)
• R=4 (marked in the recapture sample)

Using the formula:

• N₂ = (40×60)/4 = 600

Day 3:

• M=40+(60−4)=96 (40 already marked, plus 56 newly marked grasshoppers)
• C=50 (recaptured grasshoppers)
• R=7 (marked in the recapture sample)

Using the formula:

• N₃ = (96×50)/7 =685.71≈686

Day 4:

• M=96+(50−7)=139 (96 already marked, plus 43 newly marked grasshoppers)
• C=25 (recaptured grasshoppers)
• R=6 (marked in the recapture sample)

Using the formula:

• N₄ = (139×25)/6 =579.17≈579

Average Population Size:
Now, the average population size can be calculated from the three estimates (N₂ ,N₃ ,N₄):

Mean = (600+686+579)/3 =1865/3 ≈ 621.67

Thus, the estimated population size based on the mean of the three observations is approximately 622 grasshoppers.

The correct answer is 30

Explanation:

Environmental filtering refers to the process by which certain species from a regional species pool are selected to be part of a local community based on their ability to thrive in specific environmental conditions. This filtering often results in a reduced number of species in the local community compared to the broader regional pool.

Factors to Consider:

1. Regional Species Pool: This is the total number of species available in a larger geographic area, which in this case comprises 60 species.
2. Local Species Pool: This is the subset of the regional pool that can persist and reproduce in the local environment. Due to environmental filtering, not all species in the regional pool will be suitable for the local conditions.
3. Environmental Filtering: The process typically reduces species richness in the local pool. Depending on the environmental constraints (e.g., soil type, climate, competition), many species may be excluded from the local community.

Local Species Pool:

Given that environmental filtering tends to significantly reduce the number of species that can coexist in a specific habitat, it’s reasonable to expect that the local species pool would be much smaller than the regional species pool. In many ecological contexts, the local species pool could be around half or less of the regional pool, especially in more specialized environments.

In this case, a local species pool of 30 species represents a significant filtering from the 60 species available in the regional pool, aligning well with the principles of environmental filtering.

Therefore, the likely local species pool of this community is 30.

The correct answer is Parapatric speciation

Concept:

• Speciation is the process by which independently evolving lineages, i.e., species, are formed.
• It involves the divergence of populations into distinct species through genetic differentiation and reproductive isolation.

Explanation:

• Parapatric Speciation:
  • This type of speciation occurs between adjacent populations within a broadly continuous habitat.
  • Unlike allopatric speciation, there is no physical barrier separating the populations.
  • Gene flow is reduced due to environmental gradients or differences in selection pressures across the habitat.
  • Over time, these differences can lead to reproductive isolation and the formation of new species.

Other Options (Incorrect):

• Allopatric Speciation:
  • Occurs when populations are geographically separated by physical barriers such as mountains, rivers, or oceans.
  • Isolation prevents gene flow between populations, leading to divergence and speciation.
• Peripatric Speciation:
  • Similar to allopatric speciation but involves a small population isolated at the edge of a larger population.
  • Genetic drift and selection pressures in the isolated population lead to rapid speciation.
• Sympatric Speciation:
  • Occurs without geographical separation.
  • New species arise within the same habitat through mechanisms such as polyploidy, sexual selection, or ecological niche differentiation.

The correct answer is Option 3 i.e.High edge-to-area ratio of the reserve

Concept:

• Conservation of biodiversity refers to the protection, upliftment, restoration and management of natural resources (flora and fauna). 
• The following are the objectives of biodiversity conservation:
• Conservation of species diversity.
• Sustainable use of ecosystem and species.

Biodiversity conservation can be divided into two - 

1. In-situ conservation - The preservation of species in their natural habitat is referred to as in-situ conservation of biodiversity. The natural ecology is preserved and safeguarded using this technique.
   • National park - It is a reserve of land protected by the government where human activities like hunting, grazing, and farming are strictly prohibited. For e.g., Kaziranga National Park, Assam, Periyar National Park, Kerala, etc.
   • Biological reserves -Biosphere reserves are protected regions where native wildlife and domesticated flora and animals are all safeguarded. Human activities like tourism and research are allowed here.
   • Wildlife sanctuaries - In the region, only wildlife is protected. Human activities like logging, farming, the gathering of woods and other forest products are permitted here as long as they do not interfere with conservation initiatives. Tourism is allowed here as well. 
2. Ex-situ conservation - ​The conservation of biodiversity out of its natural habitat is called ex-situ conservation. Zoos, botanical gardens, gene banks, nurseries, etc. are a few examples of ex-situ conservation. ​

Explanation:

Option 1: 

• Generally, reserves that are connected by wildlife corridors are better than non-connected reserves. 
• Hence, this is an incorrect option. 

Option 2: 

• A reserve should have one or more buffer zone rings around the core areas.
• The buffer zone protects the core area from human activities thereby preserving the habitat and thus the species inhabiting the core areas as well
• Hence, this is an incorrect option. 

Option 3: 

• An ideal reserve should have a low edge-to-area ratio. 
• Because if the edge-to-area ratio is low then the amount of area that is subjected to edge conditions is also less.
• The edges of the forest are more subjected to harsh conditions like higher temperatures, lower humidity, etc, and some species cannot tolerate these conditions and cannot survive on the edge of the reserve. 
• So it is ideal that the reserve is compacted with a round shape instead of an elongated shape so as to minimise land area experiencing edge conditions. 
• Hence, this is the correct option. 

Option 4: 

• Ideally, a nature reserve should have a perfect circle shape because it reduces dispersal distances and avoids detrimental edge effects. 
• Hence, this is an incorrect option.

Hence, the correct answer is Option 3.

The correct answer is Option 3 i.e. A-near, B-far, C-small, D-large

Concept:

• According to the theory of island biogeography, an island's landmass area and degree of isolation both influence how many plant and animal species exist there.
• According to the notion, smaller, more remote islands contain fewer plant and animal species. The opposite is also accurate.
• The richness and quantity of plant and animal species are greater on larger, less isolated islands.
• Larger, less remote islands generally make it simpler for species to locate one another and contain a variety of habitats. 
• In the 1960s, Robert H. MacArthur and Edward O. Wilson, two ecologists, developed this idea.

Explanation:

• The number of species found on the island depends on three contrasting processes:

1. Immigration
2. Emigration
3. Extinction

• The act of a species establishing a home in a new ecosystem is referred to as immigration.
• When an island is bigger, there is a better probability that a species can move there.
• The islands which are large and near have more immigration rate.
• While the islands which are small and far have lower immigration rates.
• A species migrating away from its established habitat is known as emigration. Because their environments no longer meet their demands for survival or growth, species leave them. 
• The islands which are large have fewer emigration rates.
• While The islands which are small have more emigration rate.
• Extinction means the death of species. An island's level of isolation and land area both have an impact on its extinction rate. Islands that are smaller and more remote experience more extinctions.

Therefore, Option C (A-near, B-far, C-small, D-large) is correct.

The correct answer is A, B and D

Key Points

• The survival of plants depends on their ability to make the most of the sunlight received from the sun. 
• Through the process of photosynthesis, plants capture light energy and convert it into food, to survive. 
• To adequately capture this valuable resource, plant leaves have adapted to survive in shade as well as the sun. 
• The leaves found at the top of the canopy and received direct sunlight are called sun leaves while the leaves that are present below the canopy (shaded region) and do not receive direct sunlight are called shade leaves.

Sun leaves and shade leaves can interchange as per the situation of the sunlight. 

1. Higher amount of chlorophyll per dry weight: Shade leaves generally have higher levels of chlorophyll per unit dry weight. This is because they need to maximize light absorption in low-light conditions. More chlorophyll allows them to capture the limited light available more efficiently for photosynthesis.
2. Lower density of stomata: Shade leaves typically have a lower density of stomata compared to sun leaves. Stomata are the pores on leaf surfaces through which gas exchange occurs. In shaded environments, water loss through transpiration is less of a concern, so having fewer stomata helps conserve water without significantly affecting CO₂ uptake for photosynthesis.​
3. Thicker leaves: Sun leaves are usually thicker than shade leaves. Thicker leaves have more cell layers, including a well-developed palisade layer, which can help protect against intense sunlight and reduce water loss. Shade leaves, on the other hand, tend to be thinner because they do not need as much structural reinforcement and want to maximize the light captured by each cell layer.

4. Lower rates of dark respiration per unit area: Shade leaves generally exhibit lower rates of dark respiration per unit area. Dark respiration is the process by which plants consume oxygen and produce CO₂ in the absence of light, using up energy reserves. Lower dark respiration rates in shade leaves help conserve energy, which is important in low-light environments where energy production through photosynthesis is limited.

Explanation:

• High amount of chlorophyll per dry weight is found in the shade leaves.
• Lower density of stomata is found in the shade leaves as compared to sun leaves.
• Sun leaves are thicker.
• Lower rates of dark respiration per unit area is found in shade leaves.
• So, statements A, B, and D are correct regarding the shade leaves.

Hence, the correct answer is option 3.

The correct answer is Tropical Forest > Temperate Forest > Tundra > Desert

Explanation:

1. Net Primary Productivity (NPP): The rate at which plants in an ecosystem produce net useful chemical energy; it is equal to the difference between the total energy captured through photosynthesis (Gross Primary Productivity, or GPP) and the energy respired by the plants. Typically measured in grams of carbon per square meter per year 
2. Leaf Area Index (LAI): A dimensionless quantity that characterizes plant canopies. It is defined as the total one-sided leaf area per unit ground surface area.
3. Season Length: The duration of the growing season, usually defined as the period of time each year during which the climatic conditions are suitable for plant growth. This might be the number of days in a year when temperature and moisture conditions allow the plants to grow.
4. NPP per Day per Unit Area: The average amount of net primary productivity produced per day by each square meter of land area in an ecosystem.

Calculation: Calculated by dividing the annual NPP by the season length. This gives a measure of the productivity rate without adjusting for the leaf area index (LAI).

Ecosystem Order According to NPP per Day per Unit Area. Based on the calculated values of NPP per day per unit area, here's the order for the given ecosystems from highest to lowest:

• Tropical Forest: 6.80 g m^-2 day^-1
• Temperate Forest: 6.20 g m^-2 day^-1
• Desert: 2.50 g m^-2 day^-1
• Tundra: 1.80 g m^-2 day^-1

Key Points 

• Desert ecosystems have a high NPP per day per unit LAI despite having relatively low overall productivity because their leaf area is highly efficient at converting available resources into biomass during their short growing season.
• Tundra follows, with relatively high efficiency in terms of daily productivity per unit leaf area, although the short growing season and low total leaf area limit overall productivity.
• Tropical Forest shows high annual productivity overall, but when broken down on a per day per unit leaf area basis, it's lower than desert or tundra because the high total leaf area dilutes the daily productivity rate.
• Temperate Forest has similar LAI to tropical forests but shorter growing seasons, resulting in slightly lower NPP per day per unit LAI compared to tropical forests.

Thus, the correct order of decreasing NPP per day per unit leaf area among the given ecosystems is Tropical Forest > Temperate Forest > Tundra > Desert