Chapter 1:The Science of Life

Biology – The study of life

Organism – Anything capable of carrying on life processes

Branches of biology – •There are many subtopics within biology – a few examples we’ll hit upon this year:

•Biochemistry – Chemical substances and processes in organisms•Genetics – Inheritance – passing of traits from one generation to nextEvolution – Change in organisms over timeCell biology – Cell structure and functionZoology – AnimalsAnatomy – Structures of organismsPhysiology – Functions, activities, and processes of organismsEcology – Interactions of organisms and environment

Characteristics of Life1. Made of cells

Can be unicellular or multicellular Multicellular organisms - more

than 1 cell Cells in these organisms are

considered specialized (have certain jobs)

Examples: some fungus, plants, and animals

Unicellular organisms - one cell 1 cell does all jobs for organismExamples: bacteria, protists, and some fungus

2. Organization – levels of organization vary based on how complex the organism is In general: cells tissues

organs organ systems organisms

Cells are the smallest unit of life, organisms the biggest

3. Living things use energy Heterotrophs are organisms that

obtain nutrients from food eaten Ex: some bacteria and

protists, fungus, & animals Autotrophs are organisms that

make their own food through photosynthesis Ex: plants, some protists, and

some bacteria

4. Homeostasis• Maintaining (relatively) constant

internal conditions (such as body temperature, pH, blood pressure, water balance) regardless of external changes Examples: sweating or

shivering to maintain body temperature

5. Living things grow and develop Growth – an increase in the number of

cells/ increase in the size Example – getting taller

Development – Changes an organism undergoes to reach adult form Example – baby kid teen

adult

6. Living things reproduce Reproduction – production of

offspring Prevents extinction of species Can be sexual or asexual

•Asexual reproduction – only 1 parent; offspring has DNA identical to parent•Sexual reproduction – 2 parents, each parent contributes ½ genetic information to offspring; offspring has mixed traits from parents

Classification •Taxonomy – The science of identifying, classifying, and naming organisms •Taxa –the categories into which organisms are classified   

The taxa: Kingdom

Phylum (Division for plants) Class

Order Family

Genus  Species

King Phillip Came Over For Good Spaghetti

Why can’t we just use common names?•Not very specific

•Ex: What KIND of frog?•Misleading

•Ex: Jellyfish is NOT a fish, ringworm is NOT a worm

•Vary by language and geography•Ex: Puma, mountain lion, and cougar are ALL the same animal!

What was wrong with the early systems of classification?•Forgot to include bacteria, fungus and protists•Failed to show proper relationships between organisms•Too general – ex. Aristotle classified animals by where they lived (air, land, or water)

 Modern system of classification:Based in part on Carolus Linnaeus’ system of binomial nomenclature (“two names”)Grouped according to physical features and their evolutionary history (phylogeny)Those placed in the same genus will be most closely related, those in different kingdoms most distantly related

Ex: Those in genus Felis are more closely related to each other than organisms in the Kingdoms Plantae and Animalia are to each other.

Writing scientific names:Ex: Homo sapiens or Homo sapiens

Can be abbreviated H. sapiensIf typed – should be italicized.If handwritten – should be underlined.First word is genus – capitalizedSecond word is species - lower case