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Characteristics of Life
Organization and Cells Response to Stimuli Homeostasis Metabolism Growth and Development Reproduction Change Through Time
Organization and Cells
CELLS- Basic unit of structure and function
ORGANIZATION- at both molecular and cellular levels- particular cells carry out specific functions
atoms molecules organelles cells organs organ systems organism
CELL STRUCTURE AND FUNCTION
Cell- basic unit of structure and function Unicellular organisms- one celled Multicellular organisms- more than one cell Cells are highly organized. Cell Differentiation- the development of
cells having special functions
Metabolism
ENERGY USE– METABOLISM – sum of all chemical processes
that occur in an organism– Energy maintains organization
Growth and Development
GROWTH- result of cell division and enlargement– Development- process by which adult organism
arises (puberty)
REPRODUCTION AND INHERITANCE
REPRODUCTION- the production of new offspring
– transmits heredity info to offspring (DNA) – gene- a short segment of DNA that contains the
instructions for the development of a single trait Sexual reproduction- the production of offspring
from the combination of genetic material from two parent organisms
Asexual reproduction- the production of offspring that does not involve the union of gametes (sex cells)
EVOLUTION
Populations of organisms evolve or change over time.
Allows for survival in a changing world Assists with the diversity of organisms
BIOLOGY THEMES
3 Themes in Biology– Diversity and Unity of Life– Interdependence of Organisms– Evolution of Life
Unity in the Diversity of Life
There are certain features that all living things have in common:– Genetic code = the rules that govern how cells
use the hereditary information in DNA– Presence of organelles
Three Domains of Life– Bacteria– Archae– Eukarya
6 Kingdoms– 4 in Eukarya (Protista, Fungi, Animalia, and
Plantae)– 1 in Arachae (Archae)– 1 in Bacteria (Bacteria)
INTERDEPENDENCE OF ORGANISMS
Ecology - the study of the interaction of organisms with one another and their environment
Ecosystems- environmental communities
Evolution of Life
Evolution = descent with modification- a process in which the inherited characteristics within populations change over generations such that genetically distinct populations and new species can develop
Natural selection = the process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals
MATTER, ENERGY AND ORGANIZATION
Living things are composed of highly organized matter
Organization requires energy Photosynthesis- energy from sun is changed into a
form of energy that can be used by living things autotrophic- make their own food (producers) Heterotrophs- organisms that must take in food to
meet their energy needs (consumers)
Steps of the Scientific Method
Make an observation with the senses Ask a question about the observation Collect data Hypothesize Prediction Experiment Draw Conclusions Communicate
COLLECTING DATA
DATA- all info gathered in trying to answer a
question- includes:– Observation
Qualitative- what we see or gather with senses
– Measuring Quantitative- what we measure using instruments and
numbers
– Sampling- using a small part to represent the entire population; which must be large and random
– Organizing data- charts, graphs, tables, maps etc
HYPOTHESIS
DEFINITION- A STATEMENT THAT EXPLAINS A SCIENTIST’S OBSERVATIONS AND DATA AND CAN BE TESTED– Can be proved wrong, but can never be proved
beyond all doubt– Are often refined, revised or discarded based on
new evidence
PREDICTION
A STATEMENT MADE IN ADVANCE THAT STATES THE RESULTS THAT WILL BE OBTAINED FROM TESTING A HYPOTHESIS
“IF…..THEN……..
EXPERIMENT
DEFINITION: testing a hypothesis or prediction by gathering data under controlled conditions
CONTROLLED EXPERIMENT involves the following:– Control group- a group or individual that serves
as a standard of comparison with another group or individual to which it is identical except for one factor- “the norm”
(Experiment cont.)
– EXPERIMENTAL GROUP- group or individual that is exposed to the factor/variable
– INDEPENDENT VARIABLE- an experimentally manipulated variable- the one thing you are testing- that you change
– DEPENDENT VARIABLE- the responding variable in an experiment (results for action of the independent variable)
ANALYZING DATA FROM EXPERIMENT
IS DATA RELIABLE? OFFER SUPPORT? REJECT?
MAKE STATISTICS; COMPARE WITH OTHER STUDIES
LOOK FOR SOURCES OF ERRORS
DRAWING CONCLUSIONS
Model- an explanation supported by data Inference- a conclusion made on the basis
of facts or premises rather than on direct observations
Theory- a broad and comprehensive statement of what is believed to be true, supported by considerable experimental evidence from related hypothesis
COMMUNICATION
Report findings in journals, at meetings, etc. Allows scientists to repeat and/or expand on previous work
MICROSCOPES
MAGNIFICATION- the increase of an object’s size to allow viewing
RESOLUTION- the power to show details clearly
FOUR BASIC TYPES OF MICROSCOPES:– Compound light microscope (LM)– Stereomicroscope– Transmission electron microscope (TEM)– Scanning electron microscope (SEM)
LIGHT MICROSCOPE
Light transfers through a thin specimen on a slide
Parts of light microscope– Stage- supports slide and specimen– Objective lens- enlarges t he image – Ocular lens- magnifies image even more– Nosepiece- holds and rotates the objectives– Diaphragm - changes the amount of light to
reach the specimen
– Course focus/adjustment- the focus to be used at lower powers- DO NOT USE AT HIGH POWER
– Fine focus/adjustment- the focus to be used at high power for more precise images
– Power of magnification- the total amount of magnification- ocular lens is 10 X
Multiply 10X by the objective lens– Ex. 10x X 40x = 400 power
Eye piece
Ocular lensBody tube
NosepieceObjective lens
StageDiaphragm
Light source
Course adjustment
Fine adjustment
Base
STEREOMICROSCOPE
Used to view larger objects Usually only has 2 objectives- ours has a 5
and 10 power
TRANSMISSION ELECTRON MICROSCOPE
Transmits a beam of electrons through a thin slice
Focuses on a screen or photographic plate Can magnify up to 200,000 times BUT cannot be used to view live specimens
SCANNING ELECTRON MICROSCOPE
Three-dimensional images- no living Specimens are not sliced- but are sprayed
with a metal coating which emits a shower of electrons when the beam of electrons is passed over it
Electrons are passed onto a photographic plate
Magnify up to 100,000 times
MEASUREMENT
SI= Systeme International d’Unites BASE UNITS-
– Length = meter = m– Mass = kilogram = kg– Time = second = s– Electric current = ampere = A– Temperature = Kelvin = K– Amount of substance = mole = mol– Volume = liter = l
Metric Prefixes
Based on the power of ten– Kilo 1000– Hecto 100– Deka 10– Meter, liter,gram– Deci .1– Centi .01– Milli .001– Micro .000001– Nano .000000001