1. Classifying and Exploring Life
Chapter Introduction
Lesson 1: Characteristics of Life
Lesson 2: Classifying Organisms
Lesson 3: Exploring Life
Chapter Wrap-Up

2. What are living things, and how can they be classified?
Classifying and Exploring Life
What are living things, and how can they be classified?

3. Classifying and Exploring Life
Dropped Dinner Rolls?
Look at the photo at the beginning of the chapter. At first glance, you might think someone dropped dinner rolls on a pile of rocks. These objects might look like dinner rolls, but they’re not.
What do you think the objects are? Do you think they are alive?
Why do you think they look like this?
What are living things, and how can they be classified?

4. 1
Characteristics of Life
What do you think?

5. 1 Characteristics of Life Do you agree or disagree?
All living things move.
The Sun provides energy for almost all organisms on Earth.

6. Classifying and Exploring Life
Lesson 1: Characteristics of Life
An organism is classified as a living thing because it has all the characteristics of life.
All living things are organized, grow and develop, reproduce, respond to stimuli, maintain homeostasis, and use energy.

7. 1 Characteristics of Life
What characteristics do all living things share?

8. 1 Characteristics of Life organism cell unicellular multicellular
homeostasis

9. 1 Characteristics of Life What’s missing?
Look at the photo at the beginning of the lesson. This toy looks like a dog and can move, but it is a robot. What characteristics are missing to make it alive? Let’s find out.

10. 1 Characteristics of Life All living things move.
Do you agree or disagree?
All living things move.
Disagree. Movement is not a characteristic of all living things.

11. 1 Characteristics of Life
Do you agree or disagree?
The Sun provides energy for almost all organisms on Earth.
Agree. Most organisms use energy from the Sun for all the processes they perform.

12. 1 Characteristics of Life
What characteristics do all living things share?
All living things are organized, grow and develop, reproduce, respond to stimuli, maintain homeostasis, and use energy.

13. Classifying and Exploring Life
What are living things, and how can they be classified?
All living things have certain characteristics in common and can be classified using several methods. The invention of the microscope has enabled us to explore life further, which has led to changes in classification.

14. Classifying and Exploring Life
Lesson 2: Classifying Organisms
Living things are classified into different groups based on physical or molecular similarities.
Some species are known by many different common names. To avoid confusion, every species has a scientific name based on a system called binomial nomenclature.

15. 2
Classifying Organisms
What do you think?

16. 2 Classifying Organisms Do you agree or disagree?
A dichotomous key can be used to identify an unknown organism.
Physical similarities are the only traits used to classify organisms.

17. 2 Classifying Organisms
What methods are used to classify living things into groups?
Why does every species have a scientific name?

18. 2 Classifying Organisms binomial nomenclature species genus
dichotomous key
cladogram

19. 2 Classifying Organisms Alike or Not?
Look at the photo at the beginning of the lesson. In a band, instruments are organized into groups, such as brass and woodwinds. The instruments in a group are alike in many ways. In a similar way, living things are classified into groups. Why are living things classified?

20. 2 Classifying Organisms
Do you agree or disagree?
A dichotomous key can be used to identify an unknown organism.
Agree. The series of questions in a dichotomous key leads to an organism’s identity.

21. 2 Classifying Organisms
Do you agree or disagree?
Physical similarities are the only traits used to classify organisms.
Disagree. Physical similarities, molecular similarities, and ancestral relationships are used to classify organisms.

22. 2 Classifying Organisms
What methods are used to classify living things into groups?
Living things are classified into different groups based on physical or molecular similarities.

23. 2 Classifying Organisms Why does every species have a scientific name?
Some species are known by many different common names. To avoid confusion, every species has a scientific name based on a system called binomial nomenclature.

24. 3
Exploring Life
What do you think?

25. Classifying and Exploring Life
Lesson 3: Exploring Life
The invention of microscopes allowed scientists to view cells, which enabled them to further explore and classify life.
A light microscope uses light and has one or more lenses to enlarge an image up to about 1,500 times its original size. An electron microscope uses a magnetic field to direct beams of electrons, and it enlarges an image 100,000 times or more.

26. 3 Exploring Life Do you agree or disagree?
Most cells are too small to be seen with the unaided eye.
Only scientists use microscopes.

27. 3
Exploring Life
How did microscopes change our ideas about living things?
What are the types of microscopes and how do they compare?

28. 3 Exploring Life light microscope compound microscope
electron microscope

29. 3 Exploring Life Giant Insect?
Look at the photo at the beginning of the lesson. Although this might look like a giant insect, it is a photo of a small tick taken with a high-powered microscope. This type of microscope can enlarge an image of an object up to 200,000 times. How can seeing an enlarged image of a living thing help you
understand life?

30. 3
Exploring Life
Do you agree or disagree?
Most cells are too small to be seen with the unaided eye.
Agree. Most cells need to be magnified hundreds of times in order to be studied.

31. 3 Exploring Life Only scientists use microscopes.
Do you agree or disagree?
Only scientists use microscopes.
Disagree. Microscopes are used by many different types of people, including forensic scientists, health-care workers, and manufacturing technicians.

32. 3 Exploring Life Only scientists use microscopes.
Do you agree or disagree?
Only scientists use microscopes.
Disagree. Microscopes are used by many different types of people, including forensic scientists, health-care workers, and manufacturing technicians.

33. 3
Exploring Life
How did microscopes change our ideas about living things?
The invention of microscopes allowed scientists to view cells, which enabled them to further explore and classify life.

34. 3
Exploring Life
What are the types of microscopes and how do they compare?
A light microscope uses light and has one or more lenses to enlarge an image up to about 1,500 times its original size. An electron microscope uses a magnetic field to direct beams of electrons, and it enlarges an image 100,000 times or more.