Ecology Practice Questions
IGCSE (Cambridge) · IGCSE Biology · 147 free MCQs with instant results and detailed explanations.
147
Total
45
Easy
76
Medium
26
Hard
Start Practicing Ecology
Take a timed quiz or customize your practice session
Sample Questions from Ecology
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
Which of the following best describes a food chain?
A.
A sequence of organisms each dependent on the next as a source of food.
B.
A diagram showing the relationships between different species in a habitat.
C.
A complex web of interactions among various species in an ecosystem.
D.
A list of all organisms living in a specific environment.
Show Answer & Explanation
Correct Answer: A
A food chain specifically illustrates how energy flows from one organism to another in a linear sequence, making option A the best description.
Q2
Easy
In an ecosystem, which of the following roles do decomposers play?
A.
They produce energy through photosynthesis.
B.
They consume primary consumers.
C.
They break down dead organic matter.
D.
They compete with producers for sunlight.
Show Answer & Explanation
Correct Answer: C
Decomposers, such as fungi and bacteria, play a crucial role in breaking down dead organic matter, returning nutrients to the soil, which is why option C is correct.
Q3
Easy
What effect does deforestation have on local biodiversity?
A.
It increases biodiversity by creating new habitats.
B.
It has no significant impact on biodiversity.
C.
It decreases biodiversity by destroying habitats.
D.
It only affects animal species, not plants.
Show Answer & Explanation
Correct Answer: C
Deforestation leads to the destruction of habitats, which in turn decreases the variety of species living in that area, making option C the correct answer.
Q4
Medium
What is the primary source of energy for most ecosystems?
A.
Chemical energy from inorganic compounds
B.
Solar energy from the sun
C.
Geothermal energy from the earth's core
D.
Nuclear energy from radioactive materials
Show Answer & Explanation
Correct Answer: B
Solar energy from the sun is the primary source of energy for most ecosystems because plants convert it into chemical energy through photosynthesis, which serves as the foundation for food chains.
Q5
Medium
Which of the following is an example of a symbiotic relationship in ecology?
A.
A lion hunting a zebra
B.
Clownfish living among sea anemones
C.
Trees competing for sunlight
D.
Mushrooms decomposing dead material
Show Answer & Explanation
Correct Answer: B
The clownfish and sea anemones have a mutualistic symbiotic relationship, where both species benefit; the clownfish gets protection and the anemone receives nutrients from the clownfish's waste.
Q6
Medium
A population of rabbits in a forest has a growth rate of 15% per year. If the current population is 200 rabbits, what will the population be in one year?
A.
230
B.
240
C.
250
D.
260
Show Answer & Explanation
Correct Answer: A
The future population can be calculated using the formula: future population = current population + (growth rate × current population). Thus, 200 + (0.15 × 200) = 230 rabbits.
Q7
Medium
Which of the following factors is most likely to decrease biodiversity in an ecosystem?
A.
Introduction of invasive species
B.
Conservation efforts
C.
Natural disasters
D.
Increased habitat diversity
Show Answer & Explanation
Correct Answer: A
The introduction of invasive species often leads to a decrease in biodiversity because these species can outcompete native species for resources, disrupting the local ecosystem balance.
Q8
Hard
In a food web, which of the following interactions is most accurately described as a mutualistic relationship?
A.
Bees pollinating flowers while feeding on nectar
B.
A hawk preying on a rabbit
C.
A tapeworm living in the intestines of a mammal
D.
A lion and a hyena competing for the same territory
Show Answer & Explanation
Correct Answer: A
Bees pollinating flowers while feeding on nectar is a mutualistic relationship because both species benefit: bees get food, and plants achieve reproduction through pollination.
Q9
Hard
In a given ecosystem, the biomass of producers is 10,000 kg, and the biomass of primary consumers is 1,000 kg. If the energy transfer efficiency between trophic levels is 10%, what is the biomass of secondary consumers in the same ecosystem?
A.
100 kg
B.
1,000 kg
C.
10 kg
D.
10,000 kg
Show Answer & Explanation
Correct Answer: A
The biomass of secondary consumers is calculated by taking 10% of the biomass of primary consumers, which is 1,000 kg. Therefore, 10% of 1,000 kg equals 100 kg.
Q10
Hard
In an aquatic environment, the introduction of a non-native species has led to a significant decline in the native fish population. Which ecological concept best explains this phenomenon?
A.
Biomagnification
B.
Competitive Exclusion Principle
C.
Trophic Cascade
D.
Eutrophication
Show Answer & Explanation
Correct Answer: B
The Competitive Exclusion Principle states that two species competing for the same resources cannot coexist. The introduction of a non-native species that competes with native fish can lead to the decline of the latter due to resource competition.
Showing 10 of 147 questions. Start a quiz to practice all questions with scoring and timer.
Practice All 147 Questions →Other IGCSE (Cambridge) Subjects
Ecology — IGCSE (Cambridge) IGCSE Biology Practice Questions Online
This page contains 147 practice MCQs for the chapter Ecology in IGCSE (Cambridge) IGCSE Biology. The questions are organized by difficulty — 45 easy, 76 medium, 26 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.