CHAPTER 1

BIOLOGY – THE SCIENCE OF LIFE

BIOLOGICAL THEMES

1. Cell Structure & Function

� cell is the basic unit of life

� all organisms are composed of at least one cell

� Unicellular – single celled ; bacteria, ameba, paramecium

� Multicellular – many celled; animals, plants, fungi

� Cell similarities

� Contain cell membrane & cytoplasm

� Contain genetic material

� Made of organic compounds (contain carbon)

BIOLOGICAL THEMES

2. STABILITY & HOMEOSTASIS

- Organisms work to maintain homeostasis – stable internal conditions

- Examples:

- Sweating

- Fever

- Increasing white blood cells

BIOLOGICAL THEMES

3. REPRODUCTION & INHERITANCE

- Reproduction – producing new organisms

- Asexual – hereditary information from organisms is not combined

- Binary fission – splitting in two

- Sexual – hereditary information from two parts of an organism or two organisms is combined

- Fertilization – egg & sperm unite

- Pollination – fertilization in plants

- Inheritance – passing of hereditary material (DNA) to offspring

BIOLOGICAL THEMES

4. Evolution

- Changing of an organism over time

- Natural selection – suggests that organisms with favorable traits called adaptations have a greater chance at survival

BIOLOGICAL THEMES

5. INTERDEPENDENCE OF ORGANISM

- Ecology – study of the interactions among organisms and their environment

- Symbiosis – relationship shared between 2 different organism

- Types of symbiosis

- Predation – one organism hunts 9 predator) and kills another (prey)

- Parasitism – one organism (parasite) lives off another (host)

- Mutualism – both organisms benefit

- Commensalism –one organism benefits while the other is unaffected

BIOLOGICAL THEMES

6. Matter, Energy & Organization

- Ways in which organism obtain, use & transfer energy

- Autotrophs – make their own food; include plants, algae & some bacteria

- Most commonly done through photosynthesis – energy from sun converted to chemical energy

AUTOTROPHS

HETEROTROPHS

- Heterotrophs – depend on others for their food

- Carnivores – eat animals

- Herbivores – eat plants

- Omnivores – eat animals & plants

- Scavengers – eat dead organisms

- Decomposers – breakdown dead plant & animal matter to simpler molecules

CHARACTERISTICS OF LIFE

� CELLS – all organisms made of at least one cell

CHARACTERISTICS OF LIFE

� Organization� 6 levels� Chemical – foundation ; atoms, molecules &

compounds� Cellular – basic unit of living things

� Eukaryotic – cell with a nucleus� Prokaryotic – cell lacking a nucleus

� Tissue – 2 or more cells performing similar functions� Organs – structures made of 2 or more tissues

performing similar function� Systems – 2 or more organs performing similar

functions� Organism – all levels working together

CHARACTERISTICS OF LIFE

� Energy use

- Metabolism – sum of all chemical reactions that occur in an organism

CHARACTERISTICS OF LIFE

� Homeostasis

- Maintaining stable internal conditions

CHARACTERISTICS OF LIFE

� Growth

-nonliving things grow by accumulating more of the material they are made of

- Living things grow through cell division & cell enlargement

- Development – how an adult organism arises

CHARACTERISTICS OF LIFE

� Reproduction

- Producing new offspring

- needed for the continuation of a species

SCIENTIFIC METHOD

� STATE THE PROBLEM OR QUESTION

� COLLECT DATA

- Observation – use of senses; qualitative

- Measuring – measured with numbers; quantitative

- Sampling – using small parts to represent an entire population

- Organizing data – place in logical order; graph, chart, table, map, diagram, etc.

SCIENTIFIC METHOD

� HYPOTHESIZING

- Statement that explains the observations & can be tested

SCIENTIFIC METHOD

� EXPERIMENTING

- Controlled experiments compare a control group with an experimental group

- Independent variable – factor which is different for the control & experimental group

- Dependent variable – results from the independent variable

- Constants – factors that are the same for both groups

� Scientists want to test the effect of sunlight on the growth of tomato plants. Each plant receives 100ml of water daily and 5 mg of plant food. Plants receive the following amounts of sunlight:

� Plant A – 0 hours

� Plant B – 4 hours

� Plant C – 6 hours

� Plant D – 8 hours

� Independent Variable – amount of sunlight

� Dependent Variable – growth of the plant� Constants – tomato plants, water & food� Control Group – Plant A � Experimental Groups – Plant B, C, D� Hypothesis

� Sunlight will affect plant growth� plants that receive more sunlight will grow

taller� Plants that receive less sunlight will not grow

SCIENTIFIC METHOD

� DRAWING CONCLUSIONS

- Does data support the hypothesis?

- Inference – a conclusion based on previous knowledge

- Theory – statement of what is thought to be true ; can be proven wrong

- Scientific Law -

SCIENTIFIC TOOLS & TECHNIQUES

A. MICROSCOPES – instrument that produces an enlarged image

� Magnification – increase of an objects size

� Resolution (resolving power) –power to show detail and distinguish between two objects

SCIENTIFIC TOOLS & TECHNIQUES

� Compound Light Microscope – uses light & a set of lenses to form an image

� Eyepiece – contains ocular lens; magnifies image 10X� Revolving nosepiece – contains the objective lenses� Objective lens – lens directly above specimen

� Low power – 4 or 10X ; shows greatest area� High power – 40X ; shows less area but more detail

� Stage – holds slide & contains an opening for light to pass through

� Iris or Diaphragm – controls amount of light passing through stage

� Total Magnification = Ocular X Objective

SCIENTIFIC TOOLS & TECHNIQUES

B. Electron Microscopes

� Use electron beams to form images

� SEM – scanning electron microscope

� TEM – transmission electron microscope

SCIENTIFIC TOOLS & TECHNIQUES

C. Chromatography

� Separation of mixtures into chemical components

D. Electrophoresis

� “carry with electricity”

� Separates fragments such as DNA & proteins

� By their size