A. What is Biology?
1. What is life?
organism- a being that exhibits all the fundamental characteristics of life.
2. Levels of organization. Living organisms can be described by levels of complexity (heirarchy of life)
a. Biosphere- The composition of the earth that comprises life or capable of producing life.
b. Ecosystem- A component of the biosphere where all living (biotic) and nonliving (abiotic) components interact.
-Rainfall and temperature ranges are large predictors of the types of ecosystems
c. Community- The biotic component of an ecosystem. This defines the group of interacting populations
d. Population- Individuals of the same species that interact within a specific community.
e. organism- the living being (e.g. tigers, butterflies, monkeys, flowers, mold, bacteria, etc.)
f. systems- groups of organs that perform a necessary living function
Most vertebrates contain 11 distinct systems: respiratory, circulatory, lymphatic, integumentary,
nervous, digestive, skeletal, muscular, male/female reproductive, endocrine, & urinary
g. organs-tissue(s) that perform(s) a specific activity within a system
ex. heart, lung, kidney, pancreas, liver, brain, spinal cord, intestine, stomach, etc.
h. tissues- groups of cells that have a common structure and function
ex. muscle, connective, epithelial, nerve, etc.
i. cells- smallest unit of life that is capable of performing all life functions
1. prokaryotic- "primitive cell". don't contain a true nucleus
2. eukaryotic- "modern cell". contain a true membrane-bound nucleus
j. organelles- membrane-bound particles within the cell that perform specific cellular functions
ex. nucleus, endoplasmic reticulum, golgi apparatus, vacuoles, vesicles, plasma membrane, etc.
k. biomolecules
1. supramolecular complexes- very large molecules (1000's of atoms)
ex. ribosomes, cytoskeleton, enzyme complexes
2. macromolecules- large molecules (100's of atoms)
ex. proteins, nucleic acids, polysaccharides, lipids
3. building blocks- molecules that serve the basis for larger molecules (10's of atoms)
ex. amino acids, nucleotides, monosaccharides, fatty acids
4. metabolites- specific molecules that have specific biological functions.
ex. pyruvate, citrate, succinate, phosphoglyceraldehyde
5. inorganic precursors- molecules that organisms use to make biomolecules. (1's of atoms)
ex. CO2, NH3, H2O, N2
l. atoms. The smallest unit of matter that still retains all properties of that matter
ex. oxygen, hydrogen, nitrogen, carbon
Resource: Level of Organization
B. Characteristics of Life.
1. All life is composed of same raw materials as nonliving objects: atoms
2. All organsims are required to obtain energy from their surrounding: ecosystem
a. autotroph- organism which can produce their own food source
b. heterotroph- organism which is dependent upon other organisms for their food source
3. All organisms show some metabolic activity - process of obtaining and storing energy
a. respiration- metabolic action which produces energy from food sources
b. photosynthesis- metabolic action which produces food from light energy
Question: How is respiration and photosynthesis related?
4. All organisms can respond to their surroundings: Environment
a. stimulus- an event that causes a change in the behaviors/characteristics of an organism/species
b. response- a reaction by an organism/species to a stimulus
c. homeostasis- processes that organisms/ecosystems utilize to maintain stability
5. All organisms are composed of cells; Plant vs. Animal Cells
a. cell- smallest unit capable of sustaining life
b. types of cells
i. prokaryotic cells lack membrane-bound organelles, specifically a nucleus
ii. eukaryotic cells have membrane bound organelles
c. organisms based on the number of cells
i. unicellular- single celled organism. example: paramecium; labeled organelles
ii. multicellular- organism composed of many cells; plant tissue
6. All organisms have potential for growth and development
a. protein synthesis- process of producing proteins within cells using DNA, RNA & ribosomes
7. All organisms have the ability to reproduce. Paramecium reproduction
-DNA is the molecule of inheritance. Copies must be passed from one generation to the next.
-Geneome is the sum accumulation of genes in an organism
-Species- organisms that belong to a viable reproductive group (horse + donkey = mule)
Asexual reproduction- production of offspring from one parent (cloning).
Sexual reproduction- production of offspring from two parents (fertilization)
8. All organisms show adaptation potential- long term or short term. Life in intertidal zones
a. evolution- process of altering life through time. genetic vs. non-genetic changes
9. Organisms show variability in form, function and behavior
a. natural selection - changes in balance of life due to nature; Darwin's finches
Question: Are viruses considered living organisms?
Game: Practice the Characteristics of Life
Review: Quiz over the Characteristics of Life
C. Scientific Method.
1. Observations & Interpretations.
a. qualitative observations: physical descriptions
b. quantitative observations: numeric description
c. interpretations: assumptions based on observations
2. Scientific Method: Guideline used in scientific research.
a. state a problem or develop a series of observations
b. develop a hypothesis: must be testable
c. devise a controlled experiment.
i. experimental groups/variables
ii. controlled groups/variables.
d. obtain & analyze data
e. draw conclusions
Flowchart: Scientific Method
