Grade 7 - Unit 1 – Interactions & Ecosystems Concepts

What are the basic needs of living things?

• Food, water, air, and shelter

• Entertainment and luxury

• Internet and social media

• Money and power

Answer explanation

Living things require basic needs to survive, which include food for energy, water for hydration, air for respiration, and shelter for protection. The other options do not represent essential needs.

Which of the following is a biotic component of an ecosystem?

• Water

• Rocks

• Species

• Air

Answer explanation

In an ecosystem, biotic components are living organisms. 'Species' refers to the various forms of life, making it a biotic component. In contrast, water, rocks, and air are abiotic factors.

What is the term for the relationship where one organism benefits and the other is not affected?

• The term is commensalism.

• The term is parasitism.

• The term is mutualism.

• The term is predation.

Answer explanation

The term commensalism describes a relationship where one organism benefits while the other is neither helped nor harmed. This distinguishes it from parasitism, mutualism, and predation, which involve different interactions.

What is the process by which plants produce food using sunlight?

• Photosynthesis

• Respiration

• Transpiration

• Fermentation

Answer explanation

Photosynthesis is the process by which plants convert sunlight into chemical energy, using carbon dioxide and water to produce glucose and oxygen. This is essential for plant growth and energy.

The role of decomposers in an ecosystem is to:

• Produce energy through photosynthesis

• Break down dead organisms and recycle nutrients

• Compete with primary producers for sunlight

• Provide shelter for small animals

Answer explanation

Decomposers play a crucial role in ecosystems by breaking down dead organisms, which recycles nutrients back into the soil, supporting plant growth and maintaining ecological balance.

What is the difference between primary and secondary succession?

• Primary succession occurs in lifeless areas, while secondary succession occurs in areas where life has previously existed.

• Primary succession occurs in areas with existing soil, while secondary succession starts on bare rock.

• Primary succession is faster than secondary succession.

• Primary succession involves only plants, while secondary succession involves animals.

Answer explanation

Primary succession begins in lifeless areas, such as bare rock, where no soil exists, while secondary succession occurs in areas that have been disturbed but still have soil and life remnants. This distinction is crucial.

What is the term for the variety of living things within an ecosystem?

• Biodiversity

• Ecosystem

• Habitat

• Population

Answer explanation

The term 'biodiversity' refers to the variety of living things within an ecosystem, including different species, genetic variations, and ecosystems themselves. It is essential for ecosystem health and resilience.

Which of the following are intervention programs aimed at preserving biodiversity?

• Habitat restoration

• Pollution increase

• Deforestation

• Species extinction

Answer explanation

Habitat restoration is an intervention program that aims to restore ecosystems and preserve biodiversity. In contrast, pollution increase, deforestation, and species extinction negatively impact biodiversity.

According to the graph, what is causing the deer population to decrease

• They got sick

• The wolf population is decreasing

• The wolf population increased

• They ran out of food

What is the role of producers in an ecosystem?

• To consume other organisms for energy

• To produce energy through photosynthesis

• To decompose organic matter

• To provide shelter for animals

Answer explanation

Producers, such as plants, play a crucial role in ecosystems by producing energy through photosynthesis. They convert sunlight into chemical energy, forming the base of the food chain and supporting all other organisms.