Introduction to Cell Biology and Genetics Notes
Characteristics of Living Organisms
- Biology is the science of life, unifying much of natural science.
- Life is complex and hard to define, constrained by chemistry and physics.
- Seven characteristics define living organisms:
- Cellular organization
- Ordered complexity
- Sensitivity
- Growth, development, and reproduction
- Energy utilization
- Homeostasis
- Evolutionary adaptation
Cellular Organization
- Cell Theory:
- All organisms are composed of one or more cells.
- Cells are life’s basic units/building blocks.
- All cells come from preexisting cells.
Ordered Complexity
- Living things are more ordered/organized than nonliving things.
Sensitivity
- Living things respond to stimuli and interact with their environment.
- Examples: Plants grow toward light, pupils dilate in response to light.
Growth, Development, and Reproduction
- Example: life cycle of a mosquito
Energy Acquisition and Utilization
- All organisms take in energy and use it to do work.
Homeostasis
- Homeostasis: Maintaining a stable internal environment through feedback self-regulation.
- Examples: Shivering/sweating to maintain body temperature, blood sugar regulation via insulin.
Evolutionary Adaptation
- Populations evolve, individuals do not.
- Evolution: genetic and phenotypic change in populations over generations.
Hierarchical Organization
- Living systems show hierarchical organization, with each level building on the level below.
Emergent Properties
- Novel properties arising from component interactions.
- Cannot be deduced solely from knowledge of individual components.
- "Life" is an emergent property.
Core Concepts of Biology
- Life is subject to chemical and physical laws.
- Structure determines function.
- Living systems transform energy and matter.
- Living systems depend on information transactions.
- Evolution explains the unity and diversity of life.