Characteristics of Living Things

Characteristics of Living Things

​Words to Know ...

These are super important vocabulary words! Be sure to write them down in your notebook and record their definitions as they appear in the presentation.

• ​​Biology

• ​Organism

• ​Autotroph

• ​Heterotroph

• ​ Cell

• ​ Mutlicellular

• ​ Unicellular

• ​Homeostasis

​Overview

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Biology is the study of all living things.

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​Living things, also called organisms, need to have certain characteristics in order to be considered living.

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​There are six characteristics of living things, as agreed upon by scientists. Something must have ALL of these characteristics in order to be considered living.

​All living things...

• Take in and use energy

• ​ Are structurally organized

• ​ Grow and develop

• ​ Reproduce

• ​ Respond to stimuli

• ​ Maintain homeostasis

​All living things use energy.

​All organisms need a source of energy to survive. Humans, for example, get our energy from the food we eat. Other living things are no different!

​Some organisms, like plants, are autotrophs, which means they use sunlight to make their own food. Others, like animals (including humans!) are heterotrophs, which means they get their food energy from other sources.

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​Organisms need energy sources to keep their systems healthy and functioning. For humans and other animals, this means things like organs, blood, and muscle. This leads us to our next characteristic ...

​All living things are organized.

​Cells are the smallest unit of life. All living things are made up of cells, which have specific roles to play in keeping organisms healthy and alive. Cells make up our organs, our blood, and our muscle tissue. Without these important systems, we could not survive!

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​Many organisms are multicellular, which means they are made of more than one cell. Others, like bacteria, are unicellular, which means the entire organism consists of just one cell.

​All living things grow and develop.

​Think about how all the ways you have changed in the last ten years. Are you taller than you used to be? Have your facial features changed? Do people tell you that you act more "mature" than you used to? These are all examples of how you have grown and developed over your lifetime.

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​Think, also, about how a plant grows from a tiny seed, or how a frog hatches from an egg as a tadpole and eventually grows legs. These, too, are examples of growth and development.

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​When multicelluar organisms grow, their cells multiply. When unicellular organisms grow, the single cell they are made of simply gets bigger in size.

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​All living things reproduce.

​Living things need to create more living things. This is how all species survive!

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​Animals give birth to live offspring. Plants release pollen into the air, and fungi (like mushrooms) release spores that land and start to grow. Unicellular organisms, like bacteria, split themselves in half to create identical "twin".

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​All of these are examples of how living things reproduce.

​All living things respond to stimuli.

​Stimuli are things or events that cause you to jump into action. There are two types of stimuli: internal and external.

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​Examples of external stimuli include squinting when the sun is too bright, or that "fight or flight" response when you sense a threat to your safety. Responding to internal stimuli helps organisms protect themselves.

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​A good example of internal stimuli is the feeling of hunger. You need to know when you're hungry so that you can take in energy to sustain yourself. All other living things do this, too!

All living things maintain homeostasis.

​Maintaining homeostasis means keeping internal conditions the same when external conditions change.

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​Think about what happens when you spend time in hot weather. You start to sweat! Sweat is your body's way of cooling down when the external temperature is too high. Similarly, your body will start to shiver when it gets too cold as a way of warming itself up.

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​All living things survive best in certain conditions. Things like shivering and sweating up your body maintain those conditions.

​Time to show off what you've learned!

​Browse back through the presentation to make sure you have all of your notes in order. Then, proceed to the quiz section of the lesson. This quiz won't be graded - it's just to check what you've learned so far!

Multiple Choice

All living things use energy. Which answer choice best describes this?

• All living things move.

• All living things need a source of food.

• A

Multiple Select

An example of how humans maintain homeostasis is... (select all correct answers)

• shivering when you are cold

• sweating when you are hot

Multiple Choice

An organism that uses sunlight to make its own food/energy source is called...

• an autotroph

• a heterotroph

Multiple Choice

An organism that gets its food/energy source from other organisms is called...

• an autotroph

• a heterotroph

Multiple Choice

Which is an example of an autotroph?

• A human

• A lion

• A sunflower

• A fish

Multiple Choice

Which is an example of a heterotroph?

• An oak tree

• Algae

• A snake

• Grass

Multiple Choice

All living things are organized. Which answer best describes this?

• All living things know what they're doing

• All living things keep clean

• All living things are made of cells that perform specific jobs

Multiple Choice

The smallest unit of life is:

• the cell

• the molecule

• the atom

• bacteria

Multiple Choice

A tadpole forming legs and becoming a frog is an example of how living things...

• are organized

• grow and develop

• reproduce

• use energy

Multiple Choice

A chicken laying eggs is an example of how living things...

• are organized

• grow and develop

• reproduce

• use energy

Multiple Choice

Eating when you feel hungry is an example of your response to...

• internal stimuli

• external stimuli

Multiple Choice

Moving out of the way of a thrown or flying object is an example of your response to...

• internal stimuli

• external stimuli