Download What Is Science? Chapter 1.1

Studying Life
Chapter 1.3
Biology = The Study Of Life
• Every living thing, although different, shares the
same 8 characteristics
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Has cells
Obtains and uses energy
Responds to stimuli / Adapts to the environment
Reproduces
Grows and develops
Has the same universal genetic code
Maintain an internal steady environment
As a group, living things change over time
Has Cells
• Cell
– The smallest living part of
an organism
• Organism can consist of 1
cell or trillions of cells
• Cells carry out specific
functions that allow
organism to survive
Obtains and Uses Energy
• All organisms must have
energy to live
• Ultimate source of energy
is the sun
• Organisms either use the
sun or other organisms
for energy
• Metabolism
– The sum of all the chemical
reactions which an
organism carries out for its
life processes
Responds to Stimuli /
Adapts to the Environment
• Stimulus
– Any change in the
environment that
causes a response
• Response
– The reaction of an
organism to a stimulus
Reproduces
• Ability to create new
offspring and continue the
species
– Asexual reproduction
• New organism has one
parent
– Sexual reproduction
• New organism has two
parents
– Fitness
• The ability to reproduce
• Only characteristic that is
necessary for the
continuation of life
Growth and Development
• Growth
– Increase in mass of an organism
• Development
– Change or maturation of an organism
Universal Genetic Code
• DNA
– Deoxyribonucleic acid
– Contains the directions
for inheritance of traits
Maintains Internal Environment
• Homeostasis
– Maintenance of an
internal steady state,
despite what is
happening in the
external environment
• Works like a thermostat
in a house
Evolution
• Change over time
• Individual organisms
cannot evolve, but
groups of organisms
can
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
Individual living
thing
Bison
Groups of
Cells
Tissues, organs,
and organ systems
Brain
Nervous tissue
Cells
Nervous system
Smallest functional
unit of life
Nerve cell
Molecules
Groups of atoms;
smallest unit of
most chemical
compounds
Water
DNA
Eye piece
Body Tube
Revolving Nosepiece
Arm
Low power objective
Medium power
objective
High power objective
Stage clips
Diaphragm
Stage
Coarse Adjustment
focus
Fine Adjustment
focus
Light Source
Base
Tools And Procedures
Chapter 1.4
The Metric System
• Most scientists use the metric system when
collecting data and performing experiments
– Also called the SI system
Why
– decimal system of measurement scaled on the
multiples of 10 – easy to use
– Everyone else uses the metric system
Measurements in the
Metric System
• Length is measured in  meters
• Mass is measured in  grams
• Volume is measured in
–  if liquid - liters
–  if solid – cubic centimeters
• Temperature is measured in degrees
0Celsius
The Microscope
• Any device that
produces magnified
images of structures
that are too small to
see with the unaided
eye
The Light Microscope vs. The
Electron Microscope
• Light Microscopes
focuses visible light rays to magnify image
can magnify up to 1000x
Example:
The Compound Light Microscope
 Uses 2 lenses and allows light to pass through specimen
 Can study dead or live organisms, no smaller than 2um.
 Uses stains or dyes to make images easier to see and 3D
Electron Microscopes
focuses beams of electrons to magnify image
produces images 1000x greater than C.L.M.
can’t observe living specimen
slides must be in a vaccuum
Examples:
• Scanning Electron Microscope (SEM)
– Electrons travel across the surface
• Transmission Electron Microscope (TEM)
– Electrons travel through thin specimen
T.E.M.
Human Cornea
Rat Liver Cells
Review Questions
• Name an organism and give an example
of how they demonstrate 5 of the 8
characteristics of life.
• Using a Venn Diagram, show the
differences and similarities between a
compound microscope and an electron
microscope.