EXPLORING LIFE

What is SCIENCE?

• Derived from the Latin verb meaning “to know”• Science is… …a process by which we know and understand how

the natural world works– Based on EVIDENCE – limits scientific study to processes

that can be observed, measured– Scientific knowledge is PROVISIONAL – evidence we have in

front of us whether developed in lab/ observations in nature

Is Science ABSOLUTE?

• Evidence CAN change!– New tools– New technology– New information

• Evidence DOES NOT provide proof or truth (we SUPPORT)• Models approximate the truth and are

susceptible to modification

• BIAS cannot always be eliminated our “thinking” colors our interpretation

How do we obtain our information?

Different TYPES of Science• Discovery Science: Describing nature• Hypothesis-based Science: Explaining nature

How are they DIFFERENT???

Discovery ScienceInvolves careful observation, measurement

Hypothesis-based Science

Scientific Method provides…

HypothesisPrediction

ExperimentObservation

Results in a body of knowledge

Law(Summary)

Theory(Explanation)

Theory vs. Law• LAW: expresses a FUNDAMENTAL principle of science (“Rule”)

– Summarizes the results of repeated observation– MUST be confirmed, agreed upon– Only applies under defined conditions– Does not explain a mechanism

Example: Newton's Law of Gravity • THEORY: explains how nature works (“Explains Rules”)

– A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing, accumulation of extensive, varied evidence

– Valid as long as there is no evidence to dispute it. Therefore, theories can be disproven.

• Regardless of which definitions one uses, scientists agree that a theory is NOT a “ law in waiting". Theories DO NOT “grow up” to be Laws!

The Culture of Science

• Scientists build on each other’s work by always remaining skeptical and by seeking reproducible evidence to confirm ideas

Science, Technology, & Society

• Scientific advances promote new technologies, which in turn enable further scientific advances and useful applications to our lives.

The Cell Theory

“All life is composed of one or more cells.”

• BUT….

What is LIFE?

Properties of Life

Levels of biological organization(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

Energy flow in an ecosystem

DNA: The Genetic Material

In each cell, the genes along the length of the DNA molecules encode the information for building the cell’s other molecules.

In this way, DNA controls the development and maintenance of the entire organism and, indirectly, everything it does.

Prkaryotic vs Eukaryotic Cells

What is the importance of Emergent Properties?

Characteristics that can be attributed to the arrangement and interactions of parts as complexity increases.

Reductionism• Breaking down complex systems to simpler

components that are more manageable to study How is this useful in

science?

Systems Biology

Focuses on the parts of the system

Focuses on how the parts influence one another; results of their interactions

Form Fits Function

Analyzing a biological structure gives us clues about what it does and how it works (FORM)

Knowing the function of something provides insight into its construction (FUNCTION)

Feedback mechanisms

regulate biological systems.

Unifying Theme: EVOLUTION• The process

of evolution (change over time) is responsible for life’s dual nature of unity and diversity

What does this statement mean?

Unity in DiversityWhile a sea horse, a jackrabbit, hummingbird, crocodile and penguin look very different, their skeletons are basically similar.

This supports the idea that the organisms living on Earth today are modified descendents of common ancestors.