1. Studying Life

2. Studying Life We know Biology means the study of life but…
What does it mean to be “alive?”

3. Characteristics of Living Things
There are a few characteristics we use to describe a living thing…

4. Characteristics of Living Things
Are made up of one or more cells
Reproduce
Are based on a universal genetic code (DNA)

5. Characteristics of Living Things
Grow and develop
Obtain and use materials and energy
Respond to their environment

6. Characteristics of Living Things
Maintain a stable internal environment
(homeostasis)
As a group will change over time
(evolution)

7. Characteristics of Living Things
Is a firefly alive?

8. Characteristics of Living Things
Is fire alive?

9. Made up of Cells Some organisms are unicellular - single celled
Cell – smallest unit of an organism that can be considered alive
Some organisms are unicellular - single celled
Others are multicellular – many cells
Multicellular organisms have very diverse cells…they can contain trillions of cells!

10. Made up of Cells

11. Reproduction All organisms produce new organisms through reproduction
Sexual Reproduction – cells from two different parents combine to form the first new cell of a new organism
Asexual Reproduction – new organisms forms from a single parent, an identical clone

12. Reproduction

13. A Universal Genetic Code
Offspring usually resemble their parents
In asexual reproduction the offspring is an exact copy of the parent
Flies produce flies, dogs produce dogs, and maple trees produce maple trees

14. A Universal Genetic Code
Deoxyribonucleic Acid (DNA) – a molecule that carries genetic information; found in all living things

15. Growth and Development
All living things grow during at least part of their lives
Growth can only occur in two ways…
In what two ways can an organism grow in size?

16. Growth and Development
Single celled organisms grow by increasing in size
Multicellular organisms can grow by increasing their number of cells
Multicellular organisms develop from a single celled egg through mitosis, or cell division

17. Need for Materials and Energy
All organisms need materials and energy to grow and to stay alive
Metabolism – the chemical reactions that occur within an organism to build up or break down materials
How do you get your energy? How to plants get theirs?

18. Response to the Environment
Organisms need to be able to detect and respond to changes around them
Stimulus – a signal that causes an organism to respond
External…the temperature in the room
Internal…the amount of sugar in your blood

19. HOMEOSTASIS
Most organisms need to keep their internal conditions constant
Temperature, amount of water, etc.
Homeostasis – Process of maintaining a stable internal environment

20. HOMEOSTASIS Similar to the thermostat in your house…
When you become cold, your body triggers you muscles to shiver to increase your body temperature
When you become too warm, your body triggers your sweat glands to sweat, bringing your body temperature back down

21. Feedback Mechanism

22. Blood Sugar
In order to maintain homeostasis you must constantly regulate your body
Insulin and blood sugar
High levels of sugar in blood  Insulin released
Low levels of sugar in blood  Glucagon released

23. Homeostasis and Blood Sugar

24. Evolution Evolution – a change in a group of organisms over time
Evolution can occur over just a few generations
Over thousands or even millions of years evolution becomes much more dramatic

26. Branches of Biology
Biology is broken into many different categories of study…

27. Zoology
Study animals

28. Botany
Study of plants

29. Paleontology
Study of ancient life

30. Physiology
Study of the function of parts of organisms

31. Ecology
The study of interactions between living things