Introduction: Themes in the study of life Lec # 1 Instructor: Dr. Hatem Eideh Course: General Biology 0200102 Reference: Reece JB, Urry LA, Cain ML, Wasserman.

Introduction: Introduction: Themes in the study of lifeThemes in the study of life

Lec # 1

Instructor: Dr. Hatem EidehCourse: General Biology 0200102

Reference:Reece JB, Urry LA, Cain ML, Wasserman SA, Minorsky PV and Jackson RB (2011). Campell Biology, 9th ed. Boston: Pearson Education. . Chap 1

Characteristics of living Characteristics of living thingsthingsWhat is life?What is biology?What are the characteristics of

living things?

Levels of Levels of biological biological organizatiorganizationon

Scientific methodsScientific methods

What the scientist is doing?What the scientist is doing?

Scientists use two main forms Scientists use two main forms of of InquiryInquiry in their study of in their study of naturenature

What is “science”?At the heart of science is “Inquiry”, the

search for information and explanation, often focusing on specific questions.

Scientists attempt to understand how natural phenomena work by using a process of inquiry that includes

Making observationsForming and testing hypotheses

Making observationsMaking observations

Describes natural structure as accurately as possible through careful observation and analysis of data

Example: cell structureTypes of data

◦ Qualitative > recorded descriptions◦ Quantitative > measurements

Inductive Reasoning: derive generalizations from a large number of specific observations

Example: “ the sun always rises in the east”; “all animals are made of cells”

Forming and testing Forming and testing HypothesesHypotheses

Observations and Inductive Reasoning stimulate us to seek natural causes and explanations for those observations

Example: what causes the plant leaf-bearing shoot to grow upward?

The role of hypothesis in the inquiry??A hypothesis is a tentative answer to a well-

framed question- an explanation on trial.Example: your flashlight fails during a

camp-out?

A campground A campground example of a example of a hypothesis-based hypothesis-based inquiry.inquiry.

Deductive Reasoning and Deductive Reasoning and Hypothesis TestingHypothesis Testing

Deduction: the “If… Then” logic of hypothesis-based science

Deduction contrasts with inductionDeductions: It is generally used after the

hypothesis has been developed, the logic flows in the opposite direction, from general to the specific

Example: if the dead battery hypothesis is correct, and you replace it with new ones, then the flashlight should work.

Example: if all organisms are made of cells, and humans are organisms, then humans are composed of cells.

A hypothesis must be : testable & falsifiable

The flexibility of scientific The flexibility of scientific methodmethod

Very few scientific inquiries adhere rigidly to the sequence of steps prescribed by the “textbook” scientific method.

You may start designing an experiment, then realizes that more observations are needed.

Experimental Controls and Experimental Controls and Repeatability Repeatability

An experiment must be designed to demonstrate the effect of ONE variable by testing control groups and experimental groups that differ in only ONE variable

Example: compare the cholesterol levels in atherosclerosis' patients with healthy persons, of same age and sex

What is the purpose of using a control group?

Experimental Controls and Experimental Controls and Repeatability Repeatability

A hallmark of science is that experimental results and observations must be repeatable

Observations that cannot be verified are interesting but cannot account as evidence in scientific inquiry

Field experiments with artificial Field experiments with artificial snakessnakes

Field experiments with artificial Field experiments with artificial snakessnakes

Theories in scienceTheories in science

A scientific theory is much broader in scope than hypothesis

Hypothesis: Mimicking the coloration of venomous snakes is an adaptation that protects non-venomous snakes from predators

Theory: evolutionary adaptations arise from natural selection

Theories in scienceTheories in science

A theory is general enough to spin off many new,, specific hypothesis that can be tested

Compared to any one hypothesis, a theory is generally supported by a much greater body of evidence

If there is “truth” in science, it is conditional, based on the preponderance of available evidence

Science benefits from a Science benefits from a cooperative approach and cooperative approach and diverse viewpointsdiverse viewpoints

Building on the work of others Cooperation is facilitated when scientists

use same model organism Science, technology and society The value of diverse viewpoints in

science