Chapter 1Principles of Life

Concept 1.1 • Living organisms share common aspects of structure, function and energy flow

• Evidence we currently have suggests that all living things have a single common ancestor.

All organisms• Are composed of a common set of chemical components.• Genetic information that uses a nearly universal code to

specify the assembly of proteins• Convert molecules obtained from their environment into

new biological molecules• Extract energy from the environment and use it to do

biological work• Regulate their internal environment• Replicate their genetic information in the same manner

when reproducing themselves• Share sequence similarities among a fundamental set of

genes

Life’s Calendar• Our History in 1 minute

• Our History in 24 hours

Concept 1.2

Genetic Systems Control the Flow, Exchange, Storage and Use of Information• Genome – sum total of all the information

encoded by an individual’s genes• Genes – portions of the DNA that can be

decoded to build proteins.• All the cells in an organism have the same DNA

but different genes are used in different cells.

Think of DNA as the letters in the words of a recipe

• The recipe is a gene• The cookbook is the

genome.• We all have a very similar

cookbook…very minor differences from one person to the next

• Each of our cells have the entire cookbook in them but only read or use about 3% of the recipes.

Concept 1.3Organisms Interact with and

Affect Their Environments• Hierarchy –biological systems are organized on

a hierarchy from basic building blocks to complete functioning ecosystems.

• Integration – Much of biology involves integrating investigations across many of the hierarchical levels.

Organisms interacting and affecting their environment

• With energy transformations: Metabolism - sum total of all the chemical transformations and other work done in all the cells of an organism

• With regulatory systems: homeostasis - the maintenance of a narrow range of conditions in the internal environment

• With competition and cooperation: symbiosis – a close, long-term relationship between individuals of two different species

Evolution Explains Both the Unity and Diversity of Life

• Evolution – a change in the genetic makeup of a population through time.

• The result of this constant change is diversity.• The first unit of study we’ll cover after this

introduction is evolution.

Why are we starting with evolution?

• “Nothing in biology makes sense except in the light of evolution”

– Theodosius Dobzhansky

• This quote emphasizes the need to integrate an evolutionary perspective into all aspects of biological study.

Science is Based on Quantifiable Observations and Experiments

• Not only should we make observations of the natural world but we also have to be able to quantify our observations.

• This means that we have to have mathematical and statistical calculations about the data we are collecting.