Chapter 1b Notes

Characteristics, Levels of Organization, Laboratory Tools and Processes

Prentice Hall pp. 16-28

Biology 1

2004-2005

Shells and Snowflakes

• How can we distinguish between living and nonliving things, such as a radiolarian (left) and a snowflake (right)? A radiolarian is a tiny living thing that is covered with a glasslike shell and lives in the ocean. A snowflake is a crystal made of frozen water.

Work with a partner to answer the following questions.

• 1. What are some similarities between the snowflake and the glass shell of the radiolarian?

• 2. What are some differences between the snowflake and the glass shell?

•

• 3. Would you classify the shell as a living thing or a nonliving thing? Explain your answer

• Both are tiny; both look crystalline.

•

• Possible answer: The snowflake was not formed by a living thing, but the glass shell was.

•

• Students will likely say that the shell is nonliving, although it once surrounded the living thing that formed it.

1–3 Studying LifeA. Characteristics of Living Things

1. Made Up of Cells2. Reproduce3. Made of DNA4. Grow and Develop5. Need Energy6. Respond to the Environment7. Maintaining Internal Balance (Homeostasis)8. Evolve (Change over time)

B. Branches of BiologyC. Levels of Organization

1. Molecules2. Cells 3. Tissues4. Organs5. Organ Systems6. Organisms7. Populations8. Communities9. Ecosystem10. Biosphere

Studying Life Biology is the science that seeks to understand the living

world (study of life).

Organism- any living thingSpecies – organisms that can produce fertile offspring

(interbreed)

All living organisms are diverse but share certain characteristics.1. Made Up of Cells2. Reproduce3. Made of DNA4. Grow and Develop5. Need Energy6. Respond to the Environment7. Maintain Internal Balance (Homeostasis)8. Evolve (Change over time)

• 1. Made Up of Cells- Living things are made up of units called cells. Cells are the smallest unit of life. Many microorganisms consist of only a single cell (unicellular). Animals and trees are multicellular (many cells).

• 2. Reproduce- Living things reproduce. Maple trees reproduce sexually. In sexual reproduction, two cells from different parents unite to produce the first cell of the new organism. In asexual reproduction, the new organism is produced by a single parent. A hydra can reproduce asexually by budding.

Characteristics of Living Organisms

3. Made of DNA- Living things are based on a universal genetic code. Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees.

4. Grow and Develop- Living things grow and develop. Flies begin life as eggs, then become maggots, and then become adult flies.

5. Need Energy- Living things obtain and use materials and energy. Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat. The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes is called metabolism.

Characteristics of Living Organisms

6. Respond to the Environment- Living things respond to their environment. A stimulus is a signal to which an organism responds. An external stimulus from the environment such as light causes the leaves and stems of plants to grow or bend toward it. An internal stimulus comes from within an organism such as blood sugar glucose dropping and your body feeling hungry.

7. Homeostasis- Living things maintain a stable internal environment. The process by which organisms keep their internal conditions relatively stable is called homeostasis. Despite changes in the temperature of the environment, a robin maintains a constant body temperature.

Characteristics of Living Organisms

8. Evolve- Taken as a group, living things change over time. Plants that live in the desert survive because they have become adapted to the conditions of the desert. Desert plants

have adapted a thicker cuticle to help prevent water loss.

• The more diversity within a species,

the greater chance that species has to

survive in a changing environment.

Characteristics of Living Organisms

Genetic Diversity within Animal Species

Div

ersi

ty

Animal Species

Zebra Cheetah Giraffe Elephant

Characteristics of Living Organisms

Characteristic ExamplesLiving things are made up of units called cells.

Living things reproduce.

Living things are based on a universal genetic code (DNA) .

Living things grow and develop.

Living things obtain and use materials and energy.

Living things respond to their environment.

Living things maintain a stable internal environment.

Taken as a group, living things change over time.

Many microorganisms consist of only a single cell. Animals and trees are multicellular.

Maple trees reproduce sexually. A hydra can reproduce asexually by budding.

Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees.

Flies begin life as eggs, then become maggots, and then become adult flies.

Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat.

Leaves and stems of plants grow toward light.

Despite changes in the temperature of the environment, a robin maintains a constant body temperature.

Plants that live in the desert survive because they have become adapted to the conditions of the desert.

Branches of Biology

• Anatomy- Physical structure of animals• Biochemistry- Chemistry of living things• Botany-Structure and function of plants• Cytology- Structure and function of cells • Ecology- Interactions of organisms and their environment• Ethology-Animal behavior in natural environments• Genetics-Heredity• Immunology- Body’s defense against diseases• Microbiology- Microscopic organisms• Paleontology- Ancient life• Taxonomy-Classification of organisms• Zoology-Structure and function of animals

The field of biology is divided into many different areas of study. Some of the examples of these groups are:

Levels of Organization

1. Molecules2. Cells 3. Tissues4. Organs5. Organ Systems6. Organisms7. Populations8. Communities9. Ecosystem10. BiosphereLargest

Smallest

Levels of OrganizationBiosphere

Ecosystem

Community

Population

The part of Earththat contains allecosystems

Community and its nonliving surroundings

Populations thatlive together in a defined area

Group of organisms of onetype that live in the same area

Biosphere

Hawk, snake, bison, prairie dog, grass, stream, rocks, air

Hawk, snake, bison, prairie dog, grass

Bison herd

Levels of OrganizationOrganism

Cells

Molecules

Individual livingthing

Tissues, organs,and organ systems

Smallest functionalunit of life

Groups of atoms;smallest unit of most chemicalcompounds

Bison

Nervous tissue Nervous systemBrain

Nerve cell

Water DNA

Organ Systems

Organs

Tissues

Groups of Cells

1–4 Tools and Procedures

A. Microscopes1. Light Microscopes

2. Electron Microscopes

B. Laboratory Techniques1. Cell Cultures

2. Cell Fractionation

C. Computers

D. Analyzing Biological Data (Graphing)

Microscopes are devices that produce larger images of structures that are too small to see

with the unaided eye

1) Light microscopes - light passes through specimen & lenses & is projected onto eye; produce magnified images by focusing visible light rays.

- magnification up to 1500x

- (ocular lens-10x X 10x objective lens)

Compound light microscopes allow light to pass through the specimen and use two lenses to form an image. Can be used on live and dead specimens

• 1000 x better than light microscopes

• Transmission electron microscopes (TEMs) shine a beam of electrons through a thin specimen. Cannot be used to study live specimens. - used to study internal structures of cells

- magnification up to 100,000x

• Scanning electron microscopes (SEMs) run a pencil-like beam of electrons back and forth across the surface of a specimen. Cannot be used to study live specimens.

- used to study surface of specimen - magnification up to 10,000x

2. Electron microscopes produce magnified images by focusing beams of electrons.

– Magnification- the amount an object is

made to look larger (through a lens)

– Resolution - the ability to distinguish two points as separate points

– Parfocal - low and high power lens are in focus with each other; an object in focus at low power will also be in focus at high power

– Field of View- circular area seen through the ocular lens

Microscope Terminology

The Compound Microscope

1. Eyepiece (ocular lens)2. Arm3. Stage 4. Opening of the stage5. Fine adjustment knob 6. Coarse adjustment knob7. Base 8. Illuminator 9. Diaphragm 10.Diaphragm lever11.Stage clips12.Low-power objective 13.High-power objective 14.Nosepiece 15.Body tube

Parts of the Microscope and their Function

1. Eyepiece Contains a magnifying lens 2. Arm Supports the body tube3. Stage Supports the slide being observed4. Opening of the stage Permits light to pass up to the eyepiece5. Fine adjustment knob Moves the body tube slightly to sharpen the image6. Coarse adjustment knob Moves the body tube to focus the image7. Base Supports the microscope8. Illuminator Produces light or reflects light up toward the eyepiece9. Diaphragm Regulates the amount of light passing up toward the eyepiece10. Diaphragm lever Opens and closes the diaphragm11. Stage clips Hold the slide in place12. Low-power objective Provides a magnification of 10× and is the shortest objective13. High-power objective Provides a magnification of 40× and is the longest objective14. Nosepiece Holds the objectives and can be rotated to change the magnification15. Body tube Maintains the proper distance between the eyepiece and the objectives

A.

B.

C. (10x)

D. (40x)

E.

F.

G.

H.

I.

J.

K.

L.

M.

Biologists use a variety of techniques to study cells.

• Cell Culture- biologists sometimes place a single cell into a dish containing a nutrient solution. The cell is able to reproduce so that a group of cells develops from the single original cell. This procedure is used to test cell responses under controlled conditions.

• Cell Fractionation- separates the different cell parts so scientists can study each part individually– Centrifuge- an instrument that can spin the tube up to

20,000 times per minute. Spinning causes the cell parts to separate

Computers - store large amounts of data- models decrease need for live animals

Reminder:     • Field studies - organism’s natural environment

- study feeding habits, interactions with environment- disadvantages - controls difficult to manage

• Lab studies - easier to control conditions- repetitions easier- specialized equipment can be used

GRAPHS:•a diagram that shows a

comparison between variables

•used to show meaningful pattern of dataTypes of Graphs:

1. Line graph –shows the relationship between 2 variables (changes or trends over time)

2. Bar graph – compares data on similar things

3. Pie graph – shows percentages of a whole (100%)

1) Determine variables a. Independent variable – you control; predetermined conditions; always goes on X-axis (horizontal axis) b. Dependent variable – depends on the independent variable; always goes on Y-axis (vertical axis)

2) Label axes – be sure to include units; ex: Time (sec.)

How to make a graph:

• 3) Number axes – include full range without using excess numbers - always label lines – not spaces - spacing between numbers must be consistent; ex. 2,4,6,8 not 2,4,6,7,8 - only “0” may go in origin (corner) of graph

4) Title – must be descriptive; written in the form “Y as a function of X” ex: “The Change in Pressure as the Temperature Rises” or “The Height (cm)

of Fertilizer Treated Tomato Plants

Over Two Week Period”

5) Legend – used when more than one set of data is plotted on the same graph a. individual lines or bars may be labeled,

OR b. lines or bars may be colored or coded

and a key (legend) provided for identification

Relative Rates of Water Released Over Time

8 A

M

10 A

M

12 P

M

2 P

M

4 P

M

6 P

M

8 P

M

TIME

Rel

ativ

e R

ates

(g/

h)

0

5

10

15

20Time

8 AM

10 AM

12 PM

2 PM

4 PM

6 PM

8 PM

Absorbedby Roots

(g/h)

10

14

9

6

4

1

1

Relative Rates of Water Released Over Time

8 A

M

10 A

M

12 P

M

2 P

M

4 P

M

6 P

M

8 P

M

TIME

Rel

ativ

e R

ates

(g/

h)

0

5

10

15

20Time

8 AM

10 AM

12 PM

2 PM

4 PM

6 PM

8 PM

Absorbedby Roots

(g/h)

10

14

9

6

4

1

1

Releasedby Leaves

(g/h)

5

2

12

17

16

10

3

Water Absorbed by roots

Water Released by leaves

pH of Various substances from the Scientific Method Lab

Substance pH

Baking soda 8

Ammonia 10

Vinegar 4

Cabbage Juice 6

Substance

pH

Baking soda ammonia vinegar cabbage juice

10

1

2

3

4

5

6

7

8

9

8

10

4

6

Ms. Parikh’s student make-up by age

Age 14 (55%)

Age 15 (25%)

Age 16 (15 %)

Age 17 (5 %)

Age %

14 55%

15 25%

16 15%

17 5%