SCIENCE 5 - 3RD TERM REVIEW

What is an ecosystem?

• A group of non-living things

• Living things only

• Interactions between living and non-living things

• A place with only plants

Answer explanation

An ecosystem consists of interactions between living (plants, animals) and non-living (water, soil) components. This choice accurately reflects the complexity of ecosystems, unlike the other options that focus on only one aspect.

Which of the following is a non-living component of an ecosystem?

• Bird

• Crab

• Water

• Algae

Answer explanation

Water is a non-living component of an ecosystem, while birds, crabs, and algae are all living organisms. Non-living components, also known as abiotic factors, include elements like water, air, and minerals.

Which best describes an estuary?

• Freshwater lake

• Deep ocean trench

• A place where river meets the sea

• Underground water cave

Answer explanation

An estuary is defined as the area where a river meets the sea, mixing freshwater and saltwater. This unique environment supports diverse ecosystems, making it distinct from a freshwater lake, deep ocean trench, or underground water cave.

What type of water is found in estuaries?

• Freshwater

• Saltwater

• Brackish water

• Rainwater

Answer explanation

Estuaries are areas where freshwater from rivers meets and mixes with saltwater from the ocean, resulting in brackish water, which has a salinity level between that of freshwater and saltwater.

Estuaries help protect human communities by:

• Drying up rivers

• Soaking up floodwater

• Creating sand dunes

• Building coral reefs

Answer explanation

Estuaries act as natural buffers, soaking up floodwater and reducing the impact of floods on human communities. This helps protect infrastructure and habitats from flood damage.

The intertidal zone is best described as:

• Deep underwater ecosystem

• Area between high and low tide

• Landlocked forest

• Underground river

Answer explanation

The intertidal zone is the area between high and low tide, where land meets the ocean. This unique ecosystem experiences varying conditions due to tidal changes, making it distinct from deep underwater ecosystems or landlocked areas.

What kind of ecosystem is the intertidal zone?

• Non-living

• Rich freshwater system

• Harsh, changing environment

• Desert ecosystem

Answer explanation

The intertidal zone is characterized by its harsh, changing environment due to the constant fluctuation of tides, which exposes organisms to varying conditions of water, temperature, and salinity.

The upper intertidal zone:

• Is submerged all the time

• Is never exposed to sunlight

• Is covered during high tide only

• Is the deepest part of the ocean

Answer explanation

The upper intertidal zone is only covered during high tide, making it periodically submerged. It is not submerged all the time, nor is it the deepest part of the ocean, and it does receive sunlight when exposed.

Which animal might be found in estuaries?

• Camel

• Mud crab

• Kangaroo

• Snake

Answer explanation

Mud crabs are commonly found in estuaries, where saltwater and freshwater mix, providing a suitable habitat. In contrast, camels, kangaroos, and snakes are not typically associated with estuarine environments.

Which intertidal zone has the most biodiversity?

• Upper zone

• Middle zone

• Lower zone

• None

Answer explanation

The lower intertidal zone has the most biodiversity due to its stable environment, greater availability of nutrients, and more habitats for various organisms compared to the upper and middle zones.