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Living Things - Habitats and local environments

Grade 3IGCSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Living things carry out seven essential life processes, often remembered by the mnemonic MRS GRENMRS\ GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.

A habitat is a specific place where a plant or animal lives. It must provide the organism with its basic needs, including food, shelter, and H2OH_2O.

Local environments are small-scale areas like a school garden, a local pond, or a woodpile. Within these are 'micro-habitats' which have specific conditions for small creatures.

Animals and plants are adapted to their environments. For example, a fish has gills to extract O2O_2 from H2OH_2O, while a cactus stores H2OH_2O to survive in dry deserts.

Identification keys (branching keys) are tools used to group and name living things by asking a series of questions based on physical characteristics.

📐Formulae

MRS GREN=Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, NutritionMRS\ GREN = \text{Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition}

Survival Needs=H2O+O2+Food+Shelter\text{Survival Needs} = H_2O + O_2 + \text{Food} + \text{Shelter}

LivingNon-livingOnce-living\text{Living} \neq \text{Non-living} \neq \text{Once-living}

💡Examples

Problem 1:

A student finds a woodlouse under a damp log. Why is the log considered its habitat, and what resource is the woodlouse seeking?

Solution:

The log is the habitat because it provides shelter and moisture. The woodlouse is seeking H2OH_2O and protection.

Explanation:

Small animals like woodlice need damp conditions to breathe and stay hydrated; the H2OH_2O trapped under the log prevents them from drying out.

Problem 2:

Classify a rock, a dried leaf, and a pet rabbit using the categories: Living, Non-living, or Once-living.

Solution:

Rabbit = Living; Dried leaf = Once-living; Rock = Non-living.

Explanation:

The rabbit undergoes MRS GRENMRS\ GREN. The leaf was part of a living tree but has stopped performing life processes, so it is once-living. The rock never performed these processes.

Problem 3:

In a local pond environment, how do plants contribute to the survival of fish?

Solution:

Plants produce O2O_2 and provide food/shelter.

Explanation:

Through biological processes, underwater plants release O2O_2 into the H2OH_2O, which fish need to breathe through their gills.