Download What is biology?

What is biology?
 Bio means “life”
 logy mean “study”
 Life” emerges at the level of
cells
 Nature
• has levels of organization
• properties emerge at
successively higher levels
 Life properties
 Organization
• More next slide!
 Metabolism
• Chemical process total (more later)
 Growth
• Increase in size or number
 Adaptability
• Adjust to changes (more later)
 Evolve
• Better fit the environment
 Irritability
• Respond to stimuli
How organisms are organized?
Atoms
 organized into
molecules
 multicelled species,
 cells organized
into tissues, organs,
and organ systems
 organisms
 consist of one or
more cells
emergent properties
 life emerges at
cellular level
We study the world of life at different levels of organization,
from atoms and molecules to the biosphere
Organisms then group as:
 Population
• individuals species
• in specific area
 Community
• populations
• in specific area
 Ecosystem
• community interacting
• with its environment
 Biosphere
• All regions of Earth that hold life
• Land, water, and atmosphere
What does life requires?
 Organisms require energy
and materials to sustain
their organization and
activities
• Nutrients are required for
growth and survival
• Producers make their own
food
• Consumers eat other
organisms
 Energy Flow and
Material Cycling
Some more features of living organisms!
 Organisms sense change
• Receptors respond to stimulation
• Responses keep internal conditions within ranges that cells
can tolerate (homeostasis)
Organization is a must!
 Organisms grow and reproduce
• Based on information encoded in DNA
• Inheritance transmits DNA from parents to offspring
through reproduction mechanisms
• Development transforms first cell into an adult
So much unity, so many species
 The world of life, past and present, shows great diversity
 Classification systems organize species in ever more
inclusive groups
 Species: One kind of organism
 Each species has a two-part name
• First part: Genus name
• Combined with the second part, it designates one particular
species
What are domains?
 Current classification groups all species into three
domains
• Bacteria (single-celled prokaryotes)
• Archaea (single-celled prokaryotes)
• Eukarya (protists, plants, fungi, and animals)
Eukarya
Bacteria
Archaea
What is critical thinking and science?
 Critical thinking is a self-directed act of judging the
quality of information as one learns
 Science is a way of looking at the natural world
• Helps minimize bias in judgments
• Focuses on testable ideas about observable aspects of nature
 Researchers generally
• Observe something in nature
• Form hypotheses (testable assumptions) about it
• Make predictions about what might occur if the hypothesis
is not wrong
• Test their predictions by observations, experiments, or both
What are experiments ?
 Tests used to support or falsify a prediction
• Variable characteristic is measured and changed
• In the control group, variables do not change
 Biological systems have many variables
 Experiments simplify observations of nature
• Focus on cause, effect, or function of one variable at a time
 Researchers design experiments to minimize potential bias
in interpreting results
What is a scientific theory?
 A well-tested hypothesis
• Explains a broad range of
observations
• Can be used to make useful
predictions about other
phenomena
 Opinion and belief are not
scientific theory