Chapter 1: Science of Biology
What is Biology?
- The study of life
How would you define life?
- Origins of life on earth
- Extraterrestrial Life (astrobiology: Study of life on other planets)
Characteristics of living organisms:
- Cellular Respiration- (Growth, Reproduction, Development) HAS CELLS
Prokaryote vs Eukaryote
- Prokaryote is unicellular, while eukaryotes have a true nucleus, they are
multicellular, and are colonial
- Organized Structure
- Metabolic Process- (Creates Energy)
Autotrophic vs Heterotrophic
- Respiration → ATP
- Homeostasis- (Brings balance to the overall cell)
- Respond stimuli - (Adaptations Movement)
- Contains heritable information- (DNA)
- Evolve- (CHANGE, Individuals cannot evolve on their own, change occurs over
time)
Are Viruses Alive?
- Viruses are organized, and able to reproduce at rapid rates, but NO THEY
ARE NOT ALIVE. They do not contain cells or DNA.
- Mitosis/ Meiosis
Levels of Organization:
Atoms → Molecules → Organelles → Cells → Tissues → Organ → Organ Systems →
Organisms → Populations → Communities → Ecosystems → Biomes → Biosphere
- Life is complex, yet it is organized
, Taxonomy- Science of classification
- Classical- Linnaeus (1700)
- Modern- Woese (1970)
Domain
1. Eukaryotic
2. Bateria
3. Archaea
Kingdom
Phylum
Class
Order
Family
Genus
Species
Subspecies
Diversity of Life
Linnaeus Taxonomic System of Classification
- In 1735 Carolus Linnaeus established the classification system still in use today.
- Binomial Nomenclature is the system for naming each organism with a unique
two part name consisting of the genus and species based on Latin.
- A genus is made up of a closely related group of species .
- Species: Same characteristics that also breed regularly
Subdisciplines encompass micro to macroscopic life
Domains- Carl Woese
- Phylogenetic tree of life
- Based upon molecular sequence data
3 Domains
- 2 Prokaryotic
- 1 Eukaryotic
- Domains are broader taxonomic fields to Linnaen Kingdoms
, What is Science?
- Knowledge of truths or laws obtained using the scientific method
- Natural vs Social → People vs Nature
- Hard vs Soft → Quantitative vs Qualitative ( ex Psychology vs Geology)
- Basic vs Applied → Practice vs Experimentation ( Medicine vs Study)
Scientific reasoning - Two types of logical thinking
- Inductive- discovery or observational science
- Deductive- theories or hypothesis leads to experiments
Scientific Method
- Process for understanding the world around us
- Test hypothesis through experimentation
- Hypothesis may lead to theories. Theories can be explain the world around us
and are time tested
, Serendipity in Science
- Not everything can be discovered through the scientific method, this is referred to
as serendipity
An example of this is Alexander Fleming, and his discovery of Penicillin, the first
antibiotic.
“In the field of observation, chance favors only the prepared mind”
Origins of Life?
Classic Idea: Spontaneous Generation
- First challenged by Francesco Redi in 1668
- FInally disproved by Louis Pasteur in 1862
- Louis Pasteur showed that cells arise from cells and not spontaneous generation
The Cell Theory
- In the late 1660s, Robert Hooke and Anton van Leeuwenhoek were the first to
observe cells.
- Hooke is known for coining the term CELLS, he thought they looked like cells
where Monks would live.
- Leeuwenhoek, Hooke, Schwann, Schieldan, Virchow
- Cells are the basic unit of life. All organisms are composed of cells, and all cells
come from preexisting cells.
Implications of the cell theory
- Because all cells come from preexisting cells, all individuals in a population of
single- celled organisms are related by common ancestry
- All cells present in multicellular organisms have descended from preexisting cells
and are connected by a common ancestry.
Life Processes Information
- Watsons and Crick Franklin
- Central Dogma
Explanation:
- DNA encodes a message in bases: A, T, C, and G
- Adenine pairs with Thymine, Cytosine pairs with Guanine
- DNA is double stranded helix
- DNA → RNA → PROTEIN