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 next Evolution – Change in organisms over time Cell biology – Cell structure and function Zoology – Animals Anatomy – Structures of organisms Physiology – Functions, activities, and processes of organisms Ecology – Interactions of organisms and environment

Characteristics of Life 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 organism Examples: 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. sapiens If typed – should be italicized. If handwritten – should be underlined. First word is genus – capitalized Second word is species - lower case