Prentice Hall pp. 16-28 Biology 1 2004-2005 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 Life A. Characteristics of Living Things 1. Made Up of Cells 2. Reproduce 3. Made of DNA 4. Grow and Develop 5. Need Energy 6. Respond to the Environment 7. Maintaining Internal Balance (Homeostasis) 8. Evolve (Change over time) B. Branches of Biology Levels of Organization 1. Molecules 2. Cells 3. Tissues 4. Organs 5. Organ Systems 6. Organisms 7. Populations 8. Communities 9. Ecosystem 10. Biosphere

Studying Life Biology is the science that seeks to understand the living world (study of life). Organism- any living thing Species – organisms that can produce fertile offspring (interbreed) All living organisms are diverse but share certain characteristics. 1. Made Up of Cells 2. Reproduce 3. Made of DNA 4. Grow and Develop 5. Need Energy 6. Respond to the Environment 7. Maintain Internal Balance (Homeostasis) 8. Evolve (Change over time)

Characteristics of Living Organisms 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. Genetic Diversity within Animal Species Diversity Animal Species Zebra Cheetah Giraffe Elephant

Characteristics of Living Organisms Examples Living things are made up of units called cells. Many microorganisms consist of only a single cell. Animals and trees are multicellular. Living things reproduce. Maple trees reproduce sexually. A hydra can reproduce asexually by budding. Living things are based on a universal genetic code (DNA) . Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees. Living things grow and develop. Flies begin life as eggs, then become maggots, and then become adult flies. Living things obtain and use materials and energy. Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat. Living things respond to their environment. Leaves and stems of plants grow toward light. Despite changes in the temperature of the environment, a robin maintains a constant body temperature. Living things maintain a stable internal environment. 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.

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

Levels of Organization Smallest 1. Molecules 2. Cells 3. Tissues 4. Organs 5. Organ Systems 6. Organisms 7. Populations 8. Communities 9. Ecosystem 10. Biosphere Largest

Levels of Organization Biosphere The part of Earth that contains all ecosystems Biosphere Ecosystem Community and its nonliving surroundings Hawk, snake, bison, prairie dog, grass, stream, rocks, air Community Populations that live together in a defined area Hawk, snake, bison, prairie dog, grass Population Group of organisms of one type that live in the same area Bison herd

Levels of Organization Organism Cells Molecules Individual living thing Tissues, organs, and organ systems Smallest functional unit of life Groups of atoms; smallest unit of most chemical compounds Bison Nervous tissue Nervous system Brain Nerve cell Water DNA Organ Systems Organs Tissues Groups of Cells

1–4 Tools and Procedures A. Microscopes B. Laboratory Techniques 1. Light Microscopes 2. Electron Microscopes B. Laboratory Techniques 1. 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

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

Microscope Terminology 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

The Compound Microscope Eyepiece (ocular lens) Arm Stage Opening of the stage Fine adjustment knob Coarse adjustment knob Base Illuminator Diaphragm Diaphragm lever Stage clips Low-power objective High-power objective Nosepiece Body tube

Parts of the Microscope and their Function Eyepiece Contains a magnifying lens Arm Supports the body tube Stage Supports the slide being observed Opening of the stage Permits light to pass up to the eyepiece Fine adjustment knob Moves the body tube slightly to sharpen the image Coarse adjustment knob Moves the body tube to focus the image Base Supports the microscope Illuminator Produces light or reflects light up toward the eyepiece Diaphragm Regulates the amount of light passing up toward the eyepiece Diaphragm lever Opens and closes the diaphragm Stage clips Hold the slide in place Low-power objective Provides a magnification of 10× and is the shortest objective High-power objective Provides a magnification of 40× and is the longest objective Nosepiece Holds the objectives and can be rotated to change the magnification Body tube Maintains the proper distance between the eyepiece and the objectives

M. A. L. B. C. (10x) K. D. (40x) E. J. F. I. H. G.

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

Field studies - organism’s natural environment 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 data Types 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%)

How to make a graph: 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) Label axes – be sure to include units; ex: Time (sec.)

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 20 Time 8 AM 10 AM 12 PM 2 PM 4 PM 6 PM 8 PM Absorbed by Roots (g/h) 10 14 9 6 4 1 1 15 10 Relative Rates (g/h) 5 2 PM 4 PM 6 PM 8 PM 12 PM 8 AM 10 AM TIME

Relative Rates of Water Released Over Time 20 Time 8 AM 10 AM 12 PM 2 PM 4 PM 6 PM 8 PM Absorbed by Roots (g/h) 10 14 9 6 4 1 Released by Leaves (g/h) 5 2 12 17 16 10 3 Water Absorbed by roots Water Released by leaves 1 15 10 Relative Rates (g/h) 5 2 PM 4 PM 6 PM 8 PM 10 AM 12 PM 8 AM TIME

pH of Various substances from the Scientific Method Lab 10 10 Substance pH Baking soda 8 Ammonia 10 Vinegar 4 Cabbage Juice 6 9 8 8 7 6 pH 6 5 4 4 3 2 1 Baking soda ammonia vinegar cabbage juice Substance

Ms. Parikh’s student make-up by age 14 55% 15 25% 16 15% 17 5% Age 15 (25%) Age 14 (55%) Age 16 (15 %) Age 17 (5 %)