Chapter 1: Learning About Life

Biology

Ø Bios = life (from Greek)

Ø -logy/-ology = scientific study of a subject

Ø Biology = scientific study of life

The word science is derived from a Latin word “scio, scire” meaning to know

Science: Systematic study of the observable world and how it works

Science: Approach to learn about the natural world based on inquiry

Science: Body of knowledge and the process to acquire this knowledge

The Scientific Method

Process consisting of a series of steps used to answer questions

Ø Is not a rigid procedure

Ø  Based on evidence to logically solve problems and answer questions

Steps of the Scientific Method

Observation

Question

Hypothesis: testable explanation of a natural phenomenon/educated guess

Prediction: statement about a condition that should occur if the hypothesis is correct

1’ Pose a scientific question

Theory: reliable explanation of important natural phenomena supported by extensive research Evolution by natural selection Atomic theory Cell theory

Fact: type of information considered to be objectively true based on current evidence Mushrooms are a type of fungus Cell membranes are made primarily of phospholipid molecules Chromosomes are found in the nucleus of eukaryotic cells

Independent variable: condition or treatment controlled by the experimenter/ treatment

Variable: a characteristic or event that differs among individuals or over time

Dependent variable: observed result that is influenced by the independent variable

Experiment: test designed to support or falsify a prediction

Experimental Constants: Aspects in the experiment that remain the same across all treatment groups and as trials are repeated

Sample size: number of individuals that are part of the experiment

Experimental group: receive a certain treatment or have certain characteristics

Controlled Experiments

Single-blind experiment: information about the experiment withheld from the participants

Double-blind experiment: neither the participants nor the experimenters know which group is the control group/ involves a third party

Control group: identical to an experimental group, but without exposure to the independent variable

Replication: Repeating the whole experiment

Baby Turtles: Do they swim or do they drift with the ocean currents?

Forms of Life Share Common Properties

Ø Atom Ø Molecule/ Biological

Molecules Ø Organelle/Cell*

§  Cells are the fundamental units of life

Ø Tissue Ø Organ

Order

Ø Organ system Ø Organism (Beyond the level of

organisms) Ø Population Ø Community Ø Ecosystem*

§  Producers §  Consumers §  Decomposers §  Physical environment

Ø Biosphere

Reproduction, Growth and Development

Ø All living organisms have DNA (deoxyribonucleic acid) that carry hereditary information and guide: Ø Development: multistep process by which the first

cell of a new multicelled organism gives rise to an adult

Ø Growth: increase in the number, size, and volume of cells

Ø Reproduction: processes by which individuals produce offspring

Nutrients and Energy Processing

How do organisms obtain energy? Ø  Producers Ø  Consumers

Why do organisms need energy? Ø  Power activities and

chemical reactions

Nutrient: substance acquired from the environment and required for growth and survival

All living organisms are capable of energy transformations and require nutrients to survive

Response to Environment

Response to a stimulus

Regulation/ Homeostasis

Living organisms have the ability to maintain a stable internal body environment even in the face of a fluctuating external environment

Evolution/ Adaptation to changing environment

Heritable traits that enable members of a population to better adapt to the changing environment Adapted individuals within a population will be more likely to survive, reproduce, and pass more of their genes on to the next generation

Major Themes in Biology

1. The Relationship of Structure to Function

The correlation of structure and function can be seen at different levels within biological systems

The indentations of the red blood cells increase the surface area through which oxygen would diffuse

Changing the shape of the active site of the enzyme renders the enzyme inactive

2. Information Flow Between all levels of biological organization

Information about glucose level in the bloodstream is received by the pancreas Pancreas releases insulin to regulate the amount of glucose in the blood

Information stored in the DNA is translated into proteins that control different body processes

3. Pathways that Transform Energy and Matter

Energy and matter transformations from one form to another makes life possible

4. Interactions within Biological Systems

Specific organization of components in a biological system and their interaction give rise to emergent properties

New properties that arise in each step upward in the hierarchy of life as a result of interactions between components and proper arrangement of components

Emergent Properties

“An organism is a living whole greater than the sum of its parts”

5. Evolution The process that has transformed life on Earth from its earliest forms to the vast diversity observed today Based on heritable changes

Evolution explains both the unity of life (descent from a common ancestor) and diversity of life (modifications that evolved as species diverged)

Darwin explained evolution by the process of natural selection