Chapter 1 Ten Themes In The Study Of Life

Hierarchy of Organization Atoms Molecules Organelles Cells Tissues Organs Systems Organism Population Community Ecosystem Biome Biosphere Ecosphere

Emergent Properties Order – tendency to self organize Reproduction – biogenesis Growth and development Energy utilization Response to the environment Homeostasis – self regulation Evolutionary adaptation

With each step upward in the hierarchy of biological order, novel properties emerge that were not present at the simpler levels of organization. “The whole is greater than the sum of its parts.”

How do we seek understanding? Reductionism – reducing complex systems to simpler components Holism – Study the entire system to truly understand it

The Cell Theory 1. All living things are composed of cells 2. All cells come from other cells 3. Cells are the units of structure and function

Two Major Kinds of Cells Prokaryotic – first cell Eukaryotic – true cell

E.M. of Prokaryotic Cells

DNA Basics DNA is the substance of genes Double helix 4 Bases (Adenine, Guanine, Cytosine, Thymine Self-replicating molecule Changes over time All forms of life employ essentially the same genetic code

Organisms Are Open Systems That Interact Continuously With Their Environments. Living things both alter and are changed by their environment Materials are recycled Energy is lost as heat and not recycled

Energy Flow In The Ecosystem

Living Systems Are Regulated Many Biological Processes Are Self -Regulating Through “Feedback” Mechanisms

Negative Feedback Positive Feedback

Evolution, Unity, And Diversity The Evolutionary Connections Among All Organisms Explain the Unity and Diversity of Life.

The Three Domains of Life

“Descent With Modification”

Connections Observation #1– Individual variation Observation #2 – Struggle for existence Inference – Differential reproductive success or “Natural Selection” Natural Selection Is An Editing Process

“Science Is A Way Of Knowing” The Process Of Science “Science Is A Way Of Knowing”

Idealized Scientific Method Inductive Reasoning

Hypothetico-deductive Reasoning “If…then” Logic

“Fishing” For Answers

Theories Have Broad Explanatory Power Theories Are Comprehensive