Introduction to Biology
What is definition of Biology?
• It is the Study of Life
• What do Biologist Study?
• Everything from tiny organisms to large
elephants.
• Even food you eat to exercise and what air and
land will be like in the future.
Biology and Society
• By studying biology we can make decisions
that impact our everyday life.
• Everyday there is news that may relate to local
issues of pollution to new inventions.
• They also work to improve the food and cures
for disease.
7 Characteristics of Life
1.
2.
3.
4.
5.
6.
7.
Organization and presence of one or more cells
Response to Stimulus (plural, Stimuli)
Homeostasis
Metabolism
Growth and Development
Reproduction
Change through time
Organization
• High degree of order within an organisms
internal and external parts and interaction
within the living world.
Cell
• All living things are made of cells
• Is the smallest unit of life
• Unicellular- organism that is made of one cell
(ex: Bacteria)
• Multicellular- organism made of one or more
cells
( ex: Humans)
• Most complex organisms have organ systems
• Organs- structures that carryout special functions within the system
• Tissues- groups of cells have similar abilities allow organ to function
• Organelles- tiny structures that carry out functions in order to stay alive
• Biological molecules- chemical compounds provide structure and provide
movement, energy, and other cellular functions for the organelle
• All biological molecules are made of atoms- the simplest particle of an
element
• Another characteristic of life is a response to a stimulus- physical or
chemical change in the internal or external environment. (ex: bright light)
Homeostasis
• Is the maintenance of a stable level of internal
conditions even when external ones change
• Regulatory systems maintain levels of
nutrients, temperature and water intake
Metabolism
• Sum of chemical reactions that take in and transform
energy and materials from environment
• Organisms use energy to power all life processes
• Plants, algae and bacteria use sun to generate sugar
molecules.
• What is this process know as?
Photosynthesis
Growth and Development
• All living things grow and increase in size
• Growth of living things comes from cell division
• Cell division is the formation of two new cells from and
existing one( fig 1-3 in book)
• Multicellular organisms mature through cell division,
cell enlargement and development
• Development- process in which organism becomes
mature adult
– It involves cell division and differentiation, or specialization
– Human body is composed of trillions of these specialized
cells. Help in carrying oxygen in body of hearing
Reproduction
• Is the process of producing organisms like themselves
• Reproduction is not essential to an individual
organisms, but it is for the species to survive
• During reproduction organisms transmit
deoxyribonucleic acid (DNA)
• A short segment of DNA is known as a gene
• Sexual reproduction- DNA from 2 different people
creates a similar but different from parents
• Asexual reproduction- DNA from only one organism is
combined for a organism that is genetically the same
Change through time
• Organisms must change and will change over
time or evolve to survive. There basic genetics
characteristics will remain the same
Diversity and Unity of Life
• Unity- features that all living things have in
common
• One feature is the genetic code in DNA
• Another feature is organelles and the activities
that they carry out.
• Diversity is defined in the tree of life and the
lineages that each organism follows. The more
similar the closer they are on the branches of the
tree. The more distantly related are on further
branches.
3 Domains of Life
• Bacteria
• Archaea
• Eukarya
• Bacteria and Archaea have less complex cells
than Eukarya
• Eukarya- most familiar organisms, animals,
plants and fungi
6 Kingdoms
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Animalia
Plantae
Fungi
Protista
Archaea
Bacteria
This is how most organisms are grouped
together
Interdependence of Organisms
• Ecology- branch of biology study organisms
interacting in an environment
• Ecosystems- communities of living species and
physical environments. Where on single
species can live
Evolution of life
• Evolution- process where inherited
characteristics change over generations, such
that new species can develop
Natural Selection
• Natural selection-organisms that have
favorable traits may survive and reproduce
more successfully than those lack these traits
• Adaptations- traits that improve ones ability
to reproduce and survive
– Ex: species that blend into environment to hide
and hunt
Scientific Method
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Steps of the Scientific Method
Although there is no single method for doing science, scientific studies involve a series of common
steps.
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1.The process of science begins with an observation. An observation is the act of perceiving a
natural occurrence that causes someone to pose a question.
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2.One tries to answer the question by forming hypotheses (singular, hypothesis). A hypothesis is a
proposed explanation for the way a particular aspect of the natural world functions.
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A prediction is a statement that forecasts what would happen in a test situation if the hypothesis
were true. A prediction is recorded for each hypothesis.
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An experiment is used to test a hypothesis and its predictions.
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Once the experiment has been concluded, the data are analyzed and used to draw conclusions.
After the data have been analyzed, the data and conclusions are communicated to scientific peers
and to the public. This way others can verify, reject, or modify the researcher’s conclusions.
Forming Hypothesis
1. Observation
2. Questioning
3. Hypothesis-making a prediction that can be tested
and gather data
4. Design an experiment
1. Control group- provides normal standard in controlled
experiment
2. Experimental group- is identical to control except for one
factor the independent variable(also known as
manipulated variable)
3. Dependent variable- responding variable or observed
changes from independent variable
Collecting and Analyzing Data
5. Quantitative Data- measuring a
variable(dependent) in numbers
– Data is collecting and compared to prior results
and then put into graphs or tables to see possible
errors and similarities
6. Drawing conclusions- using data to support the
hypothesis and to disprove only.
• Theory- set of hypothesis have been
confirmed true and confirmed by great
amount of data
• BIG BANG THEORY
• (Funny TV Show)
• Peer review- after writing a journal from the
experiment findings it is sent out for review by
other scientists anonymously for critique
Microscopes
• Compound light
• 1.Eyepiece The eyepiece(ocular(AHK-yoo-luhr) lens) magnifies the
image, usually 10 times.
• 2.Objective Lens Light passes through the specimen and then
through the objective lens, which is located directly above the
specimen. The objective lens enlarges the image of the specimen.
Scientists sometimes use stains to make the image easier to see.
• 3.Stage The stage is a platform that supports a slide holding the
specimen. The slide is placed over the opening in the stage of the
microscope.
• 4.Light Source The light source is a light bulb that provides light for
viewing the image. It can be either light reflected with a mirror or
an incandescent light from a small lamp.
• Magnification- increase in object apparent size
• Nosepiece- structure holds objective lens
• Resolution- power to show details clearly
Scanning Electron Microscope
• SEM- scans a beam of electrons over the
specimen surface giving a 3D image.
• SEM can magnify up to 100,000x
Transmission Electron
Flagellum
• TEM – transmits electrons through the
specimen to magnify up to 200,000x