BIO152H5 Lecture Notes - Lecture 1: Reductionism, Cell Theory, Natural Selection
• Biology is…
o Study of life
o Study of biodiversity of life
o Inquiry about the nature of life
• What is Life?
• Living organisms share several basic properties
1. Order
2. Energy processing
3. Regulation
4. Reproduction
5. Growth and development
6. Response to the environment
7. Evolutionary adaptation
• Properties of Life
o Camouflage is adaptation to survival
• Theme: New Properties Emerge at Each Level in the Biological Hierarchy
o Biology is organized into a hierarchy of levels
o Each higher level contains novel properties not present at the simpler level of organization
• Theme
o Abiotic into biotic
o Atoms-Molecule-Cells-Tissue-Organ-Organism
o Easier to understand
• Cells are basic unit of structure and function
• Cells are highly structured compartment
• Cell Theory:
o Proposes that all organisms are made of cells
o All living organisms are made up of one or more cells
o All cells arise from pre-exis8ng cells
o The cell is the fundamental unit of structure and function in all living organisms Energy flow
(metabolism) occurs in cells
o Cells contain hereditary information
o The continuity of life is based on heritable information
Addressing
• Reductionism
o Reducing the complex systems to simpler components
o Breaking small parts into smaller parts
• Evolution occurs when individuals with certain beneficial traits produce better offspring than
individuals lacking these traits
• The theory of evolution explains the unity and diversity of life
• 1858: Darwin proposed that all species are related by descent from a common ancestor
• Species are related to one another, but change over 8me: descent with modifica8on
• Natural selection explains how change occurs
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