Ch. 1: Exploring Life

1.Organization -The basic characteristic of life is a high degree of order. -Hierarchy of structural levels: Biosphere  Ecosystems  Communities  Populations  Organisms  Organs & Organ Sys  Tissues  Cells  Organelles  Molecules

Levels of Organization ANALOGY LEVEL EXAMPLES SCIENCE * building

2.Cells -Lowest level of hierarchy that can perform all activities required for life -Contain deoxyribonucleic acid (DNA) -Contain genes: units of inheritance -Genome: entire “library” of genes

Sperm cell Nuclei containing DNA Egg cell Fertilized egg with DNA from both parents Embryo’s cells With copies of inherited DNA Offspring with traits inherited from both parents

-DNA is made up of two long chains arranged into a double helix -Each link in the chain is 1 of 4 building blocks called nucleotides -Biological instructions are encoded on DNA -Specific sequence of nucleotides code for specific proteins

 Some living things are made up of only one cell (bacteria). Others such as ourselves, are made up of billions of cells. Plant tissue Plant leaf

-Two types of cells: 1. Prokaryotic  Simple, smaller  Example: bacteria 2. Eukaryotic  Complex  Example: human cells  Contains many compartments called organelles

3.Biological systems are much more than the sum of their parts -Emergent properties: in the hierarchy of biological order, properties emerge that are not present in the level below it. Example: Chlorophyll (molecule) cannot perform photosynthesis outside of an intact chloroplast.

-Reductionism: reducing complex systems to simpler components that are more manageable to study Example: We will study the structure of DNA -Systems Biology: Studies how all parts of a biological system is integrated (the bigger picture)  used to predict how changes will impact the whole system

4.Feedback regulation  Negative feedback: stops or slows a process (Ex. Sweating)  Positive feedback: speeds up a process (Ex. Childbirth contractions) Many biological processes are self- regulating, in which an output or product of a process regulates that process.

Enzyme 1 A A B B C C D D D D D D D D D D D Enzyme 2 Enzyme 3 Negative feedback Enzyme 1

W Enzyme 4 W X X Y Y Z Z Z Z Z Z Z Z Z Z Enzyme 5 Enzyme 6 Positive feedback Enzyme 4 Enzyme 6 Enzyme 5 Z Z Z Z Z Z Z Z Z

5.Diversity and unity of life -Diversity (1.8 million species named, million estimated) Diversity is something to relish and preserve.

Because of such diversity and complexity, scientists categorize organisms into a smaller number of groups.

There are 3 domains (Bacteria, Archaea, Eukarya) and 6 kingdoms.

-Unity among species: DNA and cell structure

6. Evolution accounts for life’s unity and diversity -Evolution is evidenced by fossils.

-Charles Darwin published “The Origin of Species” in His two main points: 1. “descent with modification”; species branch from common ancestors 2. “natural selection”; environment selects for certain favorable traits

Light colored v. Dark colored insects

-The Tree of Life: shows adaptive radiation – descent from a common ancestor

7. Science is a process of inquiry -“Science” in Latin means “to know” -Process of science involves two types of exploration:  Discovery science: describes nature through observation and analysis of data. -Data: qualitative and quantitative -Inductive reasoning: generalizations based on observation

 Hypothesis-Based Science: explains nature. The Scientific Method - Observation Question Hypothesis Prediction Test/ Experiment Test does NOT support hypothesis Test supports hypothesis; make more predictions and test them

What significant event occurred at the corner of Elm and Main in Cleveland in 1910?

8. Science and technology are functions of society -Technology results from scientific discovery -Technology is also a result of the needs of humans and the values of society