What Is Life

What Is Life

Middle School

​

Learning Objectives

• Distinguish between living, dead, and nonliving things.

• Identify the five basic needs of all living organisms.

• Describe the three primary functions performed by all living organisms.

• Explain why an object must meet all criteria to be classified as living.

Key Vocabulary

​

Organism

An organism is any living thing that exists on the planet Earth, from bacteria to plants.

​

Nonliving

This describes an object that was never alive and does not have any life processes.

​

Gas Exchange

This is the process of moving gases into and out of an organism's body.

​

Environment

The environment is the specific surroundings where an organism lives and finds its needs met.

​

Adaptations

Adaptations are the special features that help organisms survive in their particular environment or habitat.

​

Growth

This is the process by which an organism increases in its overall size over time.

Key Vocabulary

​

Reproduce

The function of creating new organisms of the same kind or species.

​

Dormant

A state where a living organism does not appear to be alive.

What is an Organism?

• An organism is anything that is currently alive.

• Something dead was once a living organism.

• Nonliving things, like rocks, were never alive.

Multiple Choice

Which of the following best defines an organism?

• Anything that is currently alive

• Anything that has ever existed

• Only things that can move on their own

• Only things that live in water

Multiple Choice

What is the main difference between something that is dead and something that is nonliving?

• A dead thing was once an organism, while a nonliving thing never was.

• A dead thing can become alive again, but a nonliving thing cannot.

• A nonliving thing is always smaller than a dead thing.

• There is no difference between something dead and something nonliving.

Multiple Choice

A fallen tree is lying on top of a large rock. How would you classify the tree and the rock?

• The tree was an organism, but the rock has always been nonliving.

• Both the tree and the rock are considered dead organisms.

• The rock is an organism because it contains a once-living thing.

• Neither the tree nor the rock can be classified using these terms.

​

​

The Needs of Living Organisms

• Organisms must exchange gases, like oxygen and carbon dioxide, to stay alive.

• Water is essential for all life and is found in food or by drinking.

• Food provides energy, and organisms must get rid of the resulting waste products.

• All organisms need a suitable environment where their adaptations help them to survive.

​

Multiple Choice

What is the primary reason that all living organisms need things like water, food, and the ability to exchange gases?

• To help them stay alive and carry out life processes.

• To allow them to move from one place to another.

• To make them grow larger than other organisms.

• To help them find a suitable environment.

Multiple Choice

What is the relationship between an organism's needs and its environment?

• The environment provides the resources that an organism needs to live.

• An organism's needs change completely from one day to the next.

• The environment is made up of the waste products of organisms.

• Organisms get energy by creating their own environment.

Multiple Choice

A species of fish lives in a river that slowly becomes polluted, reducing the amount of available oxygen in the water. What is the most likely outcome for this fish species?

• The species will struggle to survive because its need for gas exchange is not being met.

• The species will quickly adapt to get energy from the pollution.

• The species will no longer need to get rid of its waste products.

• The species will start to drink more water to get the oxygen it needs.

What Living Organisms Do

​

Respond to Environment

• All organisms react to changes in their surroundings.

• A plant’s leaves might turn toward the sun.

• An animal might run away from a predator.

​

Growth

• Living things use energy to increase in size over time.

• They use materials from food, water, and their environment.

• This process allows them to develop and become larger.

​

Reproduce

• Organisms make new organisms of their own kind.

• This process ensures the survival of the species.

• Not every individual reproduces, but the species does.

Multiple Choice

Which of the following is a fundamental characteristic of all living organisms?

• Responding to their environment

• Remaining the same size for life

• Creating their own food from sunlight

• Living in isolation from others

Multiple Choice

How do living organisms increase in size over time?

• By using materials and energy from their surroundings

• By making new organisms of their own kind

• By turning their leaves toward the sun

• By ensuring the survival of their species

Multiple Choice

If a particular species of organism stops being able to reproduce, what is the most likely consequence?

• The survival of the species might be threatened because reproduction ensures new organisms are made.

• The organisms will grow larger to adapt to the lack of reproduction.

• The organisms will learn to react to their environment instead.

• The species will find a new way to get energy from food and water.

​

Common Misconceptions

Misconception	Correction
If something moves, it must be alive.	Movement is not a key characteristic of life. Cars move but are not alive.
Anything that uses energy must be alive.	Nonliving things, like a candle, can use energy. Living things meet all eight criteria.
An organism is either living or nonliving.	There are three categories: living, dead (once-living), and nonliving (never-living).
All living things breathe through lungs.	Breathing is one form of gas exchange. Insects, for example, use breathing holes.

​

Summary

• All living things, called organisms, must meet all the criteria for life.

• Living things are different from dead things and nonliving things.

• All organisms have five basic needs and perform three essential life functions.

• Some organisms can be dormant, appearing nonliving but are actually alive.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4