1. Characteristics of Life
Ch. 1.1 – p.8-16

2. NEW SPECIES OF 2013

3. Vocabulary
 Organism – things that have all the characteristics of
life
 Cell – the smallest unit of life
 Unicellular – living things that are made of only one cell
 Multicellular – organisms made of more than one cell
 Homeostasis – an organism’s ability to maintain steady
internal conditions when outside conditions change

4. Characteristics of Life
What makes something living?

5. Basic Functions of Life
 All living things are…
 Organized
 Grow and develop
 Reproduce
 Respond
 Maintain certain internal conditions
 Use energy
*Are all of these necessary for life?
 Can you think something that fits some but not all of these
features?

6. Organization
 Living things are organized with structures that have specific functions.
 Does an organism made up of only one cell organized?

7. Unicellular Organisms
 Unicellular organisms are organisms made up of only one cell.
 Within the cell, different structures have specialized functions.

8. Multicellular organisms
 Living things that are made of more than one cell we
call multicellular.
 Multicellular organisms can be made of two cells or
trillions of cells.
 We are made up of around 37 trillion cells.
 However, cells in multicellular organisms can differ
depending on function.
 A heart cell is different from a brain cell is different from a
muscle cell is different from a skin cell is different from…

10. Growth and Development
 All living things grow!!!
 Unicellular organisms grow in size as they get older.
 As multicellular organisms grow they increase their number of cells.

11. Development
 Changes that occur in an organisms lifetime are called development.
 Development happens as cells develop and specialize into different cell
types.

14. Some developmental changes are
dramatic…some are less dramatic

15. Reproduction
 Reproduction is the process of one organism
making one or more new organisms
 Some organisms within a population might not
reproduce….that’s ok, because hopefully others
will.
 If no organisms in a population reproduce, that species
will no longer exist in that environment.
 Some organisms of a species must reproduce for
the species to survive.

16. Reproduction
 Not all organisms reproduce the same way.
 Some reproduce by division.
 Others have specialized cells for reproduction.
 Some organisms must have a mate to reproduce.
 In the end, the number of offspring a species has can also
vary.
 Frogs can produce hundreds offspring. Humans only make one or
two.

17. Response to Stimuli
 All organisms respond to changes in the environment
 These changes can be internal or external and are called stimuli.

18. Internal Stimuli

19. External Stimuli

20. Responds to light and heat
 Plants often turn towards light. This is called tropism.
 Some animals respond to temperature changes.
 What happens when you are cold?
 What happens when you are hot?

21. Homeostasis
 An organism’s ability to maintain steady internal conditions when outside
conditions change.
 Cells in certain conditions to function properly.
 Maintaining homeostasis ensures that cell work.
 If cells cannot function normally, an organism can become sick and even die.

22. Temperature classification
Core (rectal, esophageal, etc.)
Hypothermia <35.0 °C (95.0 °F)[2]
Normal 36.5–37.5 °C (97.7–99.5 °F)[3]
Fever >37.5–38.3 °C (99.5–100.9 °F)[4][5]
Hyperthermia >37.5–38.3 °C (99.5–100.9 °F)[4][5]
Hyperpyrexia >40.0–41.5 °C (104.0–106.7 °F)[6][7]
Note: The difference between fever and hyperthermia is the underlying mechanism.

23. Methods of Regulation
 How does shivering help to regulate body temperature when too cold?
 How does sweating help with too warm?
 However, there are limits to the amount of change an organism can
withstand.
 For example, a human can only survive for 5 minutes in Arctic waters before dying
due to hypothermia.

24. Unicellular homeostasis
 Unicellular organisms maintain homeostasis in different
ways.
 Paramecium, a protist, has structures called contractile
vacuoles that collect and pump out water excess water.
 Similar to how we will have to go to the toilet more if we
drink more water than normal.
 Without contractile vacuoles, the paramecium may burst if it
takes in too much water

25. Energy
 Everything you do requires energy!
 Even if you are doing nothing.
 Cells continuously use energy to transport substances, make new cells, and
perform chemical reactions.

26. Where does this energy come from?

27. Notebook Questions:
 Are cells living?
 Are the things inside cells alive?
 What is homeostasis?
 Name all 6 characteristics of a living thing?
 Think, Think, Think: How does being able to respond to stimuli allow us to
maintain homeostasis?